Fresh from curing an engine problem by replacing the fuel pump I'm back to the original braking problem that has been plaguing this van for a couple of months or more.
The brake pedal feels spongy like there's air in the lines and will travel all the way to the floor anytime the engine is running. I bled at all four wheels yet again today after rebuilding the rear brakes with new wheel cylinders, shoes, adjusters and hardware. I checked everywhere and followed all of the brakes lines out to the wheels but it is not leaking fluid anywhere that i can see as the constant level in the reservoir suggests. I have tried bleeding from the wheel farthest from the master cylinder and also starting with the wheel closest but to no avail.
On previous occasions within the last couple of months I've fitted new front pads and checked the calipers, a new master cylinder and pressure switch and bled all four wheels on numerous occasions both myself with a mittyvac and traditionally with an assistant.
When driving and I hit the brakes there is an initial grab as normal but then the pressure seems to fade and the pedal travels down until I chicken out and pump to get the vehicle slowed or to a standstill. Could this be an ABS fault in an controller, valve, hydraulic circuit or wheel sensor? there is no warning light coming on.

I'm from the old school and have never worked on the ABS part of the brake system, so I've never bothered to study it, or the power assist for that matter. Have you checked the thickness of your discs (or diameter of the drums)? If they are worn too far, one stroke of the master cylinder piston may not be quite enough.

Other than that, and assuming as you say that the system has been bled sufficiently, I would say you have a bad master cylinder. After you get them pumped up, does the pedal stay firm, or start going down again?

ken

I'm 'old school' as well workstar and never seen anything quite like this. I've already replaced the master cylinder and followed all the pre and post installation bleeding procedures.
The front rotors were replaced less than 30k miles ago, pads are brand new and the calipers work fine. I haven't checked the diameter of the drums but the wheel cylinders and shoes are new and the brakes appear to function normally when I have the wheels off the ground and an assistant press the pedal. Handbrake works fine but then it's cable operated. Everything is very well bled with clean fluid now right through the system.

Meant to say it's the 'feel' when the pedal travels down that has me thinking ABS problem. Initial grab and ok braking then fade.... pedal travels down and then a lesser grab when it's right near the bottom. Alternatively initial grab then fade then release and reapply gives grab again but fade again and repeat with lesser effect. Pedal ends up almost on the floor by the time the van is stationary.

Well short on ideas and really trying to get this van running well and safely for my wife and the three little ones I went to Autozone today and bought replacement front calipers. I fitted them this evening and bled clean fluid through but as I thought no improvement in braking. Symptoms remain as set out above.
Now I've renewed front pads and calipers, master cylinder, rear shoes and wheel cylinders with all new hardware.
Ideas appreciated on what to try next.

Meant to say it's the 'feel' when the pedal travels down that has me thinking ABS problem. Initial grab and ok braking then fade.... pedal travels down and then a lesser grab when it's right near the bottom. Alternatively initial grab then fade then release and reapply gives grab again but fade again and repeat with lesser effect. Pedal ends up almost on the floor by the time the van is stationary.

I haven't read the other posts in here yet.

On my 95 I have replaced the HCU (hydraulic control unit) once, but the bad one only caused the ABS light to come on not affecting braking function at all aside from the ABS function itself on fast stops. Though a fault in the HCU will not cause a soft or dropping pedal. Usually thats from deteriorated rubber brake lines or a leak.

Also my rear wheel cylinders have been replaced twice (were leaking) and 1 time unusually enough the Proportioning valve was leaking as well. You might check those areas as they were/are at least trouble spots on my 95.

Possible too are severaly worn pads or more likely severely worn rotors. When my rotors were at their very end of life the pads would "clap" onto them at times though the only other symptom I experienced was shuddering/shaking when coming to stops.

Also possible and could be likely is that your calipers are sticking which is causing your rotors to heat up dramatically. In my other car I had horribly gummed up slider bolts and then another time I lubed the slider bolts with the wrong grease (supposed to use specific slider bolt grease and a VERY thin film of it too). In either situation this keeps the calipers from backing off the pads/rotors causing heat up and exactly what you describe happens..... have to push it to the floor hard to get it to stop.

Hope that helps.

Quote: "When driving and I hit the brakes there is an initial grab as normal but then the pressure seems to fade and the pedal travels down until I chicken out and pump to get the vehicle slowed or to a standstill."

That is precisely what was happening to my car when the calipers were sticking/frozen keeping the pads rubbing onto the new rotors. I would bank on this if they are all 4 original calipers. I haven't looked at Windstar brakes specifically, but on other cars there are rubber boots surrounding the slider bolts. If you've ever been in standing flood water etc.. the water gets in the slider bolt bores during brake use in that water and eventually rusts out the holes and causes debris to get in too. I took mine apart and cleaned them out well and then twisted some "moderate to fine" grade sand paper in there enough times till it was rust free and smooth again and then of course recleaned it. You could perhaps use a dremel tool with a long driver extension with one of those sanding ends on it too if that exists.

Believe me this problem bewildered me for a very long time as I rebuilt my entire braking system all the way to the Master Cylinder on my car only to be met with disgust and surprise when my brakes did exactly what you describe cause of the stuck slider bolts. Autozone sells lil packets of slider bolt grease at their desks and Advance Auto sells Permatex slider bolt grease. The autozone packets have instructions on them. What you have to be really careful with is the amount of grease you use. All of the details are here for when I did it on my car: http://www.3si.org/forum/f41/slider-bolt-problems-410439/

Also, I just read that you replaced the front calipers. I doubt you bought the ones with the caliper bracket which on my 3000GT is where the slider bolt bores are. The good news is that you can do this without breaking open the fluid lines again (at least on my 3000GT) assuming the brakes are very similar on the front of the Windstar at least. Its IMPERATIVE you use the proper amount (no less or more) of slider bolt grease. The Autozone packets are .14oz and do 1 AXLE. That means that .08oz PER brake caliper which amounts to just a thin film of grease around the bolts. This job is tedious as you have to be "CLEAN" when reassembling the slider bolts and greasing.

Also, you WOULD get a brake light and/or CODE if there was air still in the lines. I believe this is kicked off by the HCU in most cases.

Aside from that I would think you'd have idling trouble if this is the case, but the brake booster is assisted by the engine vacuum. If there is a leak in the brake booster line chances are you will see the idle change a good bit when you press and release the brakes in Park. If you don't and have tried the slider bolts proper greasing method then if you've rebuilt everything else.... including the MC... then if it were me I'd try replacing the brake booster. I did this however on my 3000GT before knowing about the slider bolt greasing technique and replacing the brake booster did nothing for me as apparently they are like SUPER DOOPER heavy duty and long-lasting.

GOOD LUCK and post back your fix. You are almost there as there isn't much left to the brake system as you've ironed out everything else.

Forgot to tell the most important thing:

The slider bolt test: You should be able to (by hand) expand and contract the caliper either without the disc/rotor in place or disc in place and caliper piston(s) retracted into the caliper body. The caliper should move freely along its guide/slider bolts and even bounce back a bit after retracted. If it does not then it needs relubing/greasing especially if they don't move at all "by hand" (this is a "free" movement too... not one you should have to force).

Use brake parts cleaner to get the old gunk out, do the twisted sand paper thing if the bores are rusted inside, clean the bolts themselves till they are like new (mine I had to use a drill attaching rouded wire brush to get all the debris off them while holding the bolts at their head with a pliers or vice grip), also clean/inspect the bolt boots and if cracked anywhere replace them and if not cracked then clean them out thoroughly as well.

Well short on ideas and really trying to get this van running well and safely for my wife and the three little ones I went to Autozone today and bought replacement front calipers. I fitted them this evening and bled clean fluid through but as I thought no improvement in braking. Symptoms remain as set out above.
Now I've renewed front pads and calipers, master cylinder, rear shoes and wheel cylinders with all new hardware.
Ideas appreciated on what to try next.Ulsterman, On mine 96 windstar I replaced all the lines in the rear of the vehicle, with a couple in the middle of the van. Let me tell you what a job was it to get a firm brake pedal.The trick is your patience and a lot of brake fluid. In your case I would jack up all 4 wheels and bleed using the trickle method. I would run min 2 pints of fluid in each wheel into a jar. Because you have a couple of air bubbles in the line, usually there in the rear lines. Hint I never used them, but I will next time is speed bleeders for wheel cylinders and calipers. This will aid in quick bleeding of the system ( about $10.00 bucks ea.). When you start bleeding the calipers I would use a rubber mallet to tap on them gently to loosen any air bubbles.After your done on each wheel tighten ea. bleeder tight but don't overdo it. This worked for me and I didn't have an assistant.

There are several good ideas already posted. I would re-emphasize lubrication of caliper bolts and rear-shoe-to-backing-plates.

Make sure the rear pistons are not stuck in place. You should be able to slide the piston assembly forward-backward with your fingers.

Its hard to better the old "assistant method" of bleeding brakes.

After installing a master cylinder, it is wise to bleed it ... right there at the firewall ... by loosening the tube nuts on the master cylinder body, just as you would with a wheel bleed screw ... of course, using the assistant. After the master cyl is done ... then do the wheels.

The ABS is not your problem.

Thanks for all the replies guys. I accept it's a straightforward 'air in the system issue' and will go back to first principles and bleed from the master cylinder on out to each wheel.
Rained off today in MD so I'll get back to it after work during the week.

I think you have covered all the bases. I do not think it's air, if it was you would not have the initial high pedal that drops off. It would go right to the point where the air was compressed.

Does the pedal also start high and drop off when the vehicle is parked with engine runing?? If it does there are only 2 things that can cause it. A bad master cylinder (I know it's already been replaced) or a leak. You say you are not loosing fluid so it's not a leak.

To rule out the master cylinder remove the lines and plug the outlets on the master cylinder. start the engine and stand on the pedal, if it drops away the master is bypassing internaly. Caution: leave the vehicle in park when you try this because hard pedal or not you will have no brakes with the lines disconnected.

Thanks for all the replies guys. I accept it's a straightforward 'air in the system issue' and will go back to first principles and bleed from the master cylinder on out to each wheel.
Rained off today in MD so I'll get back to it after work during the week.

I will be very surprised if it is "air" in the system at all unless you are not bleeding the system correctly. On my import car there is a specific order to do it and its not always the same on other vehicles. I do not know what it is on the Windstar, but even still you have bled the system multiple times with no success.

My money is on the guide/slider bolts; IE: stuck/frozen calipers and your rotors heating up and why this makes sense is that you reported that the pedal gradually gets worse "as you drive" .... as you drive the heat builds and makes the brakes almost usless and the bummer about that is that if you keep it up you'll ruin/warp your NEW and OLD rotors possibly beyond repair of a resurface.

If its not that then I'd bank on old rubber lines having lost their firmness, but this is much less likely cause they'd have to be changing size dramatically as you push the pedal to cause what you are saying.

Good luck. Report back !

Ulsterman,

I have a 98 windstar and I currently have the exact problem you have been chasing.

To date, new drums and shoes, new pads, rotors and calipers. Most of the lines have also been replaced.

As I had to have the vehicle certified, I left most of the bleeding honors to a mechanic. He bled the brakes repeatedly but never corrected the problem. At last we spoke he wanted to replace my master cylinder but I had some lingering doubts and didn't want to spend the big $ for a master cylinder until I had a chance to do some research.

I have suspected that air has been my problem all along as I have checked the rear wheel cylinders (pretty much the only other thing not to have been replaced at the corners) and rear adjustment, all are good.

I too need the vehicle safe and reliable for my wife and babe.

I think I will pursue the brake bleeding issue further...

Perhaps we can compare notes here shortly.

Thanks for all the replies folks.
I can rule out the stuck caliper pins right away Searcherr, I've had them out they're as new and greased up and sliding freely. I can watch each caliper move the pads and grab the rotor when an assistant presses the brake pedal.
I appreciate your views Rotorman and 12Ounce and others about patience and bleeding and running a lot of fluid through and I intend to continue this process once MD dries up a little after two days rain. I returned the old calipers to Autozone yesterday and picked up speed bleeders for the front calipers (they claimed they didn't have ones for the rear cylinders) but I'll check against the old units this evening. Patience is not something I'm noted for so I'll have to force myself to take time over this.
Hyguy just watch this post and I'll update once I get a dry evening here. I'd welcome hearing of any progress you make.

Overall I actually like this van. It looks good, has a good safety record and drives a treat and we've had good service from it. I did the lower intake manifold gaskets 3 years ago and last week replaced the fuel pump. We look forward to another few years with a bit of luck!

Thanks for all the replies folks.
I can rule out the stuck caliper pins right away Searcherr, I've had them out they're as new and greased up and sliding freely. I can watch each caliper move the pads and grab the rotor when an assistant presses the brake pedal.
I appreciate your views Rotorman and 12Ounce and others about patience and bleeding and running a lot of fluid through and I intend to continue this process once MD dries up a little after two days rain. I returned the old calipers to Autozone yesterday and picked up speed bleeders for the front calipers (they claimed they didn't have ones for the rear cylinders) but I'll check against the old units this evening. Patience is not something I'm noted for so I'll have to force myself to take time over this.
Hyguy just watch this post and I'll update once I get a dry evening here. I'd welcome hearing of any progress you make.

Overall I actually like this van. It looks good, has a good safety record and drives a treat and we've had good service from it. I did the lower intake manifold gaskets 3 years ago and last week replaced the fuel pump. We look forward to another few years with a bit of luck!One quick note there's a lot of bad rebuilt m/c's out there and Cardone seems to be one of them I hope you got a new one not a rebuilt unit. When you bleed you don't have use brand name brake fluid I used a no name one.

Rotorman the master cylinder I fitted was Raybestos professional grade bought online at Rockauto, don't think it was a reman unit and don't remember paying a core charge or I'd have returned the old one, it's still on my workbench.
This evening I fitted the speed bleeders to the front calipers and bled about a pint or more fluid through each one. This seemed to give a better pedal feel so I put on the front wheels and took it for a short drive.
Verdict...improvement but a way to go yet. The pedal still travels down maybe 3/4 way to the floor but from there I'm getting a firmer feel than previously but am having to pump to stop the vehicle anyway quick.
Tomorrow I think I'll visit the auto shop and look for speed bleeders to fit the rear wheel cylinders as I found them very handy to get a fair volume of fluid through reasonable quickly in a solo exercise.
Thanks for the speed bleeder tip Rotorman, I think I'm on the right track ok. Next I'll get all four wheels off the ground and do a serious bleeding exercise on each wheel to see if I can't get a good firm pedal.

Ulstrman

Have you adjusted the rear shoes so they are close to the drum? If you pull the parking brake (not all of the way but just before it applies) and then try braking. If the pedal doesn't go down as far, without the Ebrake slightly applied the rear shoes should be tightened up.

How far do you have to pull the Ebrake before it takes effect?

Regards

Dan

The rear brakes are well adjusted. The handbrake travel is approx 2/3 of what it used to be.
Didn't get near the van this evening, that whacky hobby called work!

Ulsterman,

I decided to break down and take the van to the Ford dealer.

They found that it was the hydraulic part of the ABS module.

The dealer part is $1000 :frown: . They can get me a used one for $350 but still estimate $1000 for the re and re plus additional parts. Bottom line $1000 to $1500. I guess I could do it myself but it look like a nasty little job. I think I'm done with this one.

Hope you fare better than me!

Best of luck.

Hyguy.

Ouch.

I guess thats possible .... its not so much ABS, but indirectly so since the HCU exists for the ABS thus if the mechanisms of it fail or get clogged over time this makes sense. This would explain why Ulsterman can't get it nabbed, but "perhaps" if his problem is slowly improving (pedal feel) over the course of several flushes the prob may go away.

Its too bad there's no machine to use to flush the brake lines repeatedly. Could purposely send air through the line during the flush and/or some kind of line detergent though I don't think that exists for brakes unless you'd send Brake Parts cleaner through the system mixed with brake fluid though I'm sure everyone will say thats a big NO NO cause of all the warnings we see to never put anything else in fluid lines except brake fluid - still it might get the job done to flush the HCU and then after you'd flush with more and more and more fluid till you are satisfied the brake parts cleaner is out.

Perhaps you could open two calipers.... pump force into one and catch out the other.. maybe reverse the flow too. This way you could hook up a small hose that fits to each end making it easy to pump out unless somehow you could pump out from the MC to 1 caliper open at a time. This is of course assuming Ulsterman's prob is in the HCU..... which at this point could be very likely since most everything else is narrowed out unless its the MC or Prop valve.

Ulsterman - I rebuilt my MC with a kit on my car. If you are thinking about redoing it you may wanna see if Ford has a rebuild kit and do it that way.

EDIT: Maybe you could unhook the HCU on the vehicle and use your hand air pump (or compressed air from a compressor maybe 20 to 35lbs) and blow in the inlets and see if GUNK forces out of the outlets then reverse it... blow IN through the outlets OUT through the inlets. It makes sense to me the HCU would be a blockage point cause its a junction.

Eliminating possibilities you've already ruled out and again this is from my 1995 Cd-ROM.

From the cd-rom:

Symptom: Brakes not working, excessive pedal travel, brake pedal (2455) feels spongy when fully applied.
Worn or damaged ABS HCU
Rear brake shoe and lining out of adjustment
Front wheel bearing end play not to specification
Brake master cylinder or power booster mounting loose
Front disc brake caliper attachment loose
Worn or damaged automatic adjusting mechanism (rear)
Glazed, worn, scored or damaged brake shoe and linings
Drums or rotors out of round (excessive runout)
Front or rear brake hoses improperly positioned
Brake master cylinder filter cap vent hole cloggedSymptom: Excessive brake pedal travel or brake pedal goes to floor consistently.

Master cylinder diagnosis
Rear brake shoe and lining out of adjustment, worn, bad wear pattern, or cracked drums
Loose or improper attachment of brake pedal, pedal support booster and brake master cylinder
Insufficient brake pedal reserve (tests for Brake booster, check valve, master cylinder,Symptom: Excessive pedal effort to fully apply brakes

Overloaded vehicle
Insufficient vacuum to power brake booster
Power brake booster and brake pedal linkage binding caused by worn bushings or corrosion.
Worn or damaged power brake booster.
Brake shoe and lining worn, glazed, contaminated or improper type.
Rear brake shoe and lining (2200) improperly installed.
Seized pistons in rear wheel cylinders (2261) or disc brake calipers (2B120).
Restricted brake lines or hoses.
Hydraulic Control Unit (HCU)

Removal

1. Disconnect 24-pin connector from anti-lock brake control module (2B373).

2. Disconnect 2-pin power and ground connector from anti-lock brake control module.

3. Remove two tubes from inlet ports and four tubes from outlet ports of HCU.

4. Remove three attaching bolts retaining EHCU assembly to the mounting bracket and lower EHCU assembly down and out of engine compartment.

5. Separate the anti-lock brake control module from the hydraulic control unit (HCU) by removing the 4-T25H Torx® head screws and the pump motor harness connector. Do not pry apart, carefully detach the anti-lock brake control module from the HCU by pulling straight apart.

EDIT: Hyguy - If thats all it is to remove that thing looks like it wouldn't be too bad. I never did it myself, but I did get an HCU for really cheap through http://www.car-part.com

Thanks for the replies guys and for all the useful info Searcherr.
When I get back to working at the van it'll be get it up on axlestands, all four wheels off and bleed, bleed, bleed. I now have speedbleeders for all four wheels so it won't actually take all that long. If I don't get a better pedal then I'll look further to this ABS unit but here's hoping.
Maurice

... don't forget to start at master cylinder.

... don't forget to start at master cylinder.

Just a thought I think possibly master cylinder bleeding might be said to be required because of there still being fluid in the lines during removal of the MC. If you were to bleed the system dry of all fluid and then begin again pouring into the MC it doesn't seem that you'd need to bleed the MC specifically, but just the calipers thereafter. I've done this on my car and it worked out fine. Though if you separate the MC before bleeding the system dry it would seem you would need to either bleed the MC or the entire system.

Also just a tip to save fluid. I use an extremely clean container (air blow it out first too) and will reuse fluid thats already been flushed and still clean if I'm constantly flushing then end it with a clean refill from the fluid bottle.

Good that you verified the fronts are not locking up on the sliders, but what about the rears on their sliders too?

Searcherrr, the rear brakes on a 98 Windstar are drums - no slider pins but they're well greased where the shoes contact the backing plates.

12Ounce I'm starting at the M/C and working out. I take it I unhook the brake lines one at a time and push some fluid through?

Yep, sometimes a bubble can lodge there just outside the master cylinder body ... it eventually will move on its own, but bleeding at the tube nuts helps advance the process. Don't take the lines loose ... just loosen the nuts a vee bit just as you would a bleed screw ... and only while the fluid is pressurized. You must have an assistant for this one.

It also gives you a second chance to make sure the tube nuts are sealing well.

Well I bled at the master cylinder just as 12Ounce described but without any improvement. Busy with family stuff but I'll belled at the four wheels later today or tomorrow.

Yesterday I bled about a quart of fluid at each wheel with an assistant pumping the pedal. I got a few air bubbles from the rear drivers side at one stage but overall only a minor improvement if any.
Took the van for a test drive. It's much the same as I described earlier in this post. The pedal will travel to 3/4 or further down to get it to a standstill; pumping will get it stopped faster.
I think I'll drive it to work for a few days then try readjusting the rear brakes and repeating the four wheel bleeding.
Overall very frustrating since it's driving very well after the engine problems I've had.
Ideas?

Have you adjusted the gap between the master cylinder and the power assist unit? I think I remember some critical small clearance there that must be maintained ... but I have not replaced a master cyl on a Winnie so this may not be the case.

Just slinging out a thought.

If there is such of an adjustment ... its usually corrected by a nut and screw clevis mounted right on the brake pedal arm.

I was thinking along those same lines today 12Ounce i.e. is there any way I can adjust the brake pedal height and maybe reduce some of the travel.
I have a Hayes manual which talks about being able to adjust the pushrod length on some brake boosters with the master cylinder unbolted and moved out of the way. I of course simply swapped out the master cylinder about a month ago now thinking I had the culprit right there.
I'll inspect and try this once we get a dry evening again here in MD.
I also intend to remove and clean the front ABS wheel sensors and generally see what sort of shape they're in. A while back I had them replaced on my chevy truck under a safety recall and it improved braking as a result - just a thought. I cleaned the rear ones when I had the drums off but haven't touched the front ones.
The saga continues...

After trying and replacing virtually everything else I would bet on the proportioning valve especially if its a "metering" valve (combination valve) as well. I am going through this with my car right now. All 4 calipers are in TIP TOP condition now and I have replaced EVERYTHING else and yet the brakes don't feel new as they SHOULD feel (IE: braking power is probably at least HALF effective). The proportioning valve is the only thing I haven't replaced and it IS responsible for loss of braking power when its also doing a Metering valve's job. There is very little information about these valves on the web because they are believed to be HULKS and are very rarely replaced though that is on a brake system that is taken care of routinely. I knew very little about brakes till I did all the work on my car and without a flush of the lines way long after it was due the fluid of course was sludge. I imagine this ate away at the proportioning valve especially with tid bits of water in the lines I'm sure from driving in flood waters in the past.

You may experience loss of power as I said with a bad proportioning (metering) valve as well as possibly brakes dragging and/or possibly vehicle pulling to one side. The best info I've seen yet on this is here at Babcox: Brake Valves: Operation and Service (http://www.babcox.com/editorial/bf/bf50014.htm)
I find that Babcox has a lot of good information that isn't normally covered so well other places.

Dunno if I said this too already, but I did have to replace my proportioning valve on my Windstar when I first got it. Thats where the "SAGA" began.

Also, note that a function (probably the main one) of the proportioning valve is to provide proper power/pressure to the rear brakes in the event of a "PANIC" braking due to weight transfer/momentum etc... Its on that Babcox page, but it says if this wasn't in place the rears would lock up or attempt to. If you think about it if you are an aggressive or "ahemmm" defensive driver (which I am) you may be using the proportioning valve more often than most vehicles do which may be a reason why it fails faster (besides not bleeding when you should) on some vehicles vs others aside from design or location on the vehicle (corrosion).

You do not need to adjust the push rod if you can tell its hitting the MC as soon as you press the pedal. Test with your hand and just push the pedal slightly (maybe 1/4 of an inch at most). You can gauge how far the rod is from the MC by sensing the "bump" or "thud" feeling you get when the rod hits the MC. If there is no small bump felt I would think your push-rod is perfectly as close to the MC as possible.

Adjusting the brake pedal height is likely not necessary though if you did adjust the bolts that move the brake height when you installed the brake booster you may have inadvertently changed the brake pedal height. In any case adjusting the brake pedal height is really a workaround rather than a fix and will probably lead to much more degraded brake performance later on if you don't nab the real cause. The brake pedal height should be set to what the factory wants it to be at all times. Changing this could cause an accident especially if you raise it cause your foot will bump it when switching from the accel pedal.

Trust me man, I went through this too on my car when I thought I found my brake pedal was too low. Turns out it was a misprint in the manual and I spent weeks wondering why things didn't feel right cause of belief in the manual.

The proportioning valve is a good candidate for a trouble source. Had a friend who was never able to "bleed" his brakes properly on his Chevy S10 until this valve was replaced.

Quite frankly, I didn't even realize the Windstar had one.

I've been bleeding and bleeding and yesterday I fitted new rear brake drums with one very slight improvement to brake performance with the pedal still travelling 3/4 way down. I looked at pedal height and at the master cylinder to pushrod contact and concluded there was nothing to adjust.
I've read everything I could find on ABS and since there's no warning lights and the fuses and the lights on ignition come on as normal I gave it the ok too.
I'll find and replace this proportioning valve as quite frankly this braking issue is driving me crazy. I've been driving and working at vehicles for 30 years and I swear I've bled more brake fluid through this one than all the others put together with little success!

Ulsterman,
You mentioned " initial grab as normal but then the pressure seems to fade"
I have had the exact same experience with my 1999 Windstar. I first noticed the problem a few days after replacing the brake pads and rotors(front).
Two weeks ago I replaced the master cylinder but no improvement.
Today I replaced the brake booster and the problem was solved. No more fade.
I got a reman A1 Cardone booster. It was very easy to install.

RickC

Good info, RickC.

Thanks for the advice RickC. I'd reckoned the brake vacuum booster was ok since I'd ran through the checks listed in the Haynes manual but I called my local Advance AP and they have one in stock so I'll pick it up on the way home today.

12Ounce I'm also picking up a proportioning valve from Ford on the way home so either it or the vacuum power booster, being all there is left to renew, should get me a result. otherwise I'll tell my wife to post the obituary on here!

Well over the course of today I fitted the new proportioning valve and bled the master cylinder and all four wheels but no change in braking performance.
Tomorrow it's the vacuum booster being the only thing, apart from ABS equipment, that I haven't changed to date.
We'll see!

May the light of success shine brightly on your back. Don't want any obits. now, do we? Good Luck and let us know.


ken - sittin here on the group w bench

This morning I installed a Cardone reman brake booster. The pedal feels stiffer i.e more force required to press down and there is some improvement in braking. There is still too much pedal travel and the stopping power is not nearly as good as it has been in the past with this van despite all the new components and hours of bleeding.
I'll drive it to work this week and see how things settle in.

Ulsterman,

When the car is cold, and you go out, start it up, and just press on the brakes, do they still travel 3/4 way down? (without driving it)

-Jerry

Jerry,
After I fitted the power booster today I started it up from cold and the pedal travels way down before braking occurs.
I took it out to go shopping with the family on board and it's exactly the same as it was last week before changing the proportioning valve and power booster; only difference is the pedal is stiffer i.e it takes more force to move it down than before due to the new power booster I'm assuming. My wife hasn't driven it today but she may not be happy with the force now required to work the brake pedal. .
When moving the brakes stop better if I go down fast on the pedal and then the braking force fades off as previously. There is still some braking power left but it's right near the floor and usually I have pumped i.e. released and reapplied before then.
If it's sitting idling like at traffic lights or in park and I keep pressure on the pedal it will slowly go right to the floor.
It's very frustrating as everything else is running so well.

I was certain that our head scratching would be over by now.

So the new booster requires lots of foot pressure. Can you double check that the vacuum hose is properly connected to the booster and that the hose is in good condition.

Have you verified that the drums and shoes are within tolerance?

A previous poster mentioned disconnecting the rear circuit brake line from the master cylinder. Your local parts store should have a brass plug that you can screw into the master cyl port. With the engine running in PARK, check brake pedal feel. If it does not sink to the floor, then you may have isolated the problem to the rear brakes.


RickC

You do not need to adjust the push rod if you can tell its hitting the MC as soon as you press the pedal. Test with your hand and just push the pedal slightly (maybe 1/4 of an inch at most). You can gauge how far the rod is from the MC by sensing the "bump" or "thud" feeling you get when the rod hits the MC. If there is no small bump felt I would think your push-rod is perfectly as close to the MC as possible.

Adjusting the brake pedal height is likely not necessary though if you did adjust the bolts that move the brake height when you installed the brake booster you may have inadvertently changed the brake pedal height. In any case adjusting the brake pedal height is really a workaround rather than a fix and will probably lead to much more degraded brake performance later on if you don't nab the real cause. The brake pedal height should be set to what the factory wants it to be at all times. Changing this could cause an accident especially if you raise it cause your foot will bump it when switching from the accel pedal.

Trust me man, I went through this too on my car when I thought I found my brake pedal was too low. Turns out it was a misprint in the manual and I spent weeks wondering why things didn't feel right cause of belief in the manual.
I'm going to reverse some of what I said in that post I'm replying to because dude I have to tell ya I have been through ALL of this exactly the same as your problem with my car and TONIGHT I just realized exactly what the problem is in my car and after almost 3 years of this problem existing I'm finally going to have it fixed.

SIMPLE and QUICK LITTLE PUSH-ROD TEST: With my sister's help I had an idea for a new test to see if the push rod clearance is good.
I had her watch the brake fluid reservoir with the top OFF of it. Brake fluid at max line. Use a flashlight.
I instructed her to watch the fluid level and to let me know when it went UP even in the slightest degree.
I went in the car and gently gently gently with both hands for "control of the push" pushed the brake pedal down slowly slowly slowly .... merrily merrily merrily life is but a dream.. oopps i trailed off sorry....
I noticed an initial immediate bump when pushing the pedal accounting for brake pedal play. Then noticed a second bump 3/8" down during downward pedal push as if the push rod was engaging late with the 2nd bump "having to be" the push rod hitting the MC back plate.
I stopped short of pushing past this 2nd bump just for a moment and then pushed it very very gently a little bit further. From the moment I pushed the pedal to the moment of the 2nd bump the brake fluid reservoir level did not move up or down AT ALL! It moved only when I pushed it past the 2nd bump. What's this mean? It means that the push-rod to master cylinder clearance is WAAAAAY off of spec. Sorry for all the colors ya'll. I'm just excited cause I have done everything Ulsterman has done to fix the brakes in my car with the same exact results as him.

From the brake pedal to the brake pads it should be like the same type of response you get from a limb on your body. This space between the rod and the MC (about 3/8") accounts for not only not being able to use all the power available for use in your brakes, but for late braking (milliseconds to seconds which count a great deal on the road) and for YOU GUESSED IT ... DRAGGING BRAKE PADS! All of which I am experiencing. I would not be surprised if your pads are dragging and if you drive behind a quiet building or somewhere with a wall near you I bet you will hear the pads scrapping unless its your ABS ECU.

Don't have time tonight, but tomorrow the first thing I'll be doing is popping the MC off and adjusting that clearance. I bet you this nabs the damn brake demons and that I ended up ordering that Prop valve for nothing at least for my car.

If this isn't the problem on your van as well then the only thing left it could be is the ABS EHCU and again I got one from a junk yard cause they are so expensive. I called around till I found one with a lot less miles than mine. (car-part.com)

The specified space shown on the graphic accounts for what can be described in English as maybe the width of a sharpened pencil tip. This is damn near touching the MC back plate which is how it should be.

For adjustment, it would seem that you should get the push-rod out enough to where it touches the MC back plate lifting it barely off the booster mounting surface and then successively back the rod off in 1/4 turns till you have it right (barely up to the mc back plate). On my car as I'd figure it would be on most booster's you adjust the push-rod length outside of the booster on the engine bay side by turning it with some pliers. Of course the MC must be off to make this adjustment. I really hope this is what it is for you cause this makes sense and would explain why everything else you did yielded little to no results.

This also explains why I had thought that my 1st stock booster was bad (still talking about my car not the van) and why the 2nd used OEM booster did the same exact thing cause this means my original booster push-rod and the 2nd used less mileage booster I bought were BOTH incorrectly adjusted too far back. Unfortunately and GOOD to know at the same time this may mean that all NA booster push rod's over time back themselves off from extended usage.

Another thought: MC back plate (unless a new one comes in the MC rebuild kit) may be bent in from too many years of pushing on it. This may be why buying a new booster still requires you to adjust the push-rod unless the new booster doesn't come preadjusted to the right length.

Hmmm. You seem excited ... and rightfully so. Nothing like putting an issue "to bed".

I would expect a booster to come to you adjusted on the "short side" ... much better to have the pedal a bit loose than to not allow the MC to fully recoil/recharge. Also, over time, the pedal assembly pivots, etc, will wear ... contributing to looseness. And the end of the push rod will wear into the master cyl piston.

I wonder in Ulsterman's case, if all wheels are properly retracting ... even the caliper piston seal rings have a dual function ... to seal on the brake pressure stroke, and to keep the caliper piston lightly against the pad on the return stroke. This forces the MC to recharge fully. Of course, even the "new" MC could be bad ... I've had it happen.

And I don't understand how a replacement booster should cause brake pedal stiffness. Maybe a another vacuum source should be tried ... perhaps a hose hook-up to another idling engine tapped directly into the booster ....

Gentlemen I'll check again this evening but I'm sure the vacuum line is ok, I simply just switched it over and reconnected the clamp.
Everything now is new in the hydraulic brake system - calipers & pads, rear wheel cylinders, drums and linings; the rear brakes are well adjusted. The system is well bled with lots of fluid taken at each wheel on Saturday.
Before I take it down off the axle stands each time I check the handbrake on and off at each rear wheel then the footbrake at all four wheels. Each wheel checks out with no dragging once the brake is released. First time on the road I check for freewheel coming off a hill at low speed and then at higher speed later; there is no binding whatsoever.
I need to catch up with grass mowing this evening but I'll check on the booster rod to m/c gap just as soon as I can and try blocking off one line from the m/c as RickC suggests.

The rear wheels should drag ... just a wee bit.

If its not the push-rod it has just got to be the ABS EHCU. My feeling from this thread is that Ulsterman would want to get a brand new one rather than a used one like I did....lol.... which is probably why he doesn't want it to be that part and hasn't spoken about it much. I don't blame him. Those things are very expensive brand new.

I would bank on the push-rod having retracted over time first before banking the new mc isn't in good shape. Lets hope.

Just in case: ABS EHCU is part number F58A-2C346-CC - May have to take the dashes out to find it on various OEM parts web sites. Keep in mind this is the part number for my HCU for my 1995 Windstar. I don't know if they kept the same one through all the 1st gens. One thing is for sure though. Don't waste your time searching for this part number online because NO ONE has it listed. I searched at least 8 web sites and none of them list it. Gonna have to call your favorite Ford parts place.

If this is in fact an ABS unit problem shouldn't I have at least a warning light.
Otherwise how can I identify that this unit is faulty or is it a case for give up and take it into a dealer for diagnostics situation. I take the EHCU is the unit underneath the battery in the engine compartment.
On the way home from work yesterday I detoured and tried out the brakes on a short downhill mountain section with no other traffic around. There is plenty of braking power there it's just right at the last 10% of brake pedal travel i.e right at the floor. I fail to see how the small amount of adjustment I observed on the brake booster to m/c rod tip could correct this even allowing for geometry on the brake pedal lever arrangement.
Also the pedal going to the floor effect considerably worsens after the vehicle has been driven for some time and things get thoroughly hot but then I suppose this is related to reduced viscosity of the brake fluid.

When you bled the brakes at the MC, could you tell if you were getting REAL pressure at each tube fitting??? My concern is that one of the double piston chambers is not doing its job.

If you do (and I would again recommend) adjusting the pedal (or booster) push rod, be sure to leave the rod end (into the MC) well lubed with a thick silicone paste. The idea is to get a suction link between the pedal/booster so that when the pedal returns it helps/tries to pull the MC back with it. .... And, of course, you want the barest of gaps between the push rod and MC.

12Ounce, when I bled the m/c I had wifey push the pedal just as we would in the normal wheel caliper bleeding process. I didn't notice any difference at either union. I can have her apply full force on the pedal to see if we get identical effects when I loosen the unions.
With my work schedule it's going to be later in the week or maybe the weekend before I can work at it again.
I called the local dealer and they want the vehicle for a whole day to diagnose so that'll be my next step.
Maurice

One more intervention (= annoyance) from me: ... What if you pull the hand brake halfway and drive this way ... does that affect the pedal travel????

Last evening I adjusted the vacuum brake booster pushrod and BINGO we have reasonable brakes. This has been the issue and well done 12Ounce and Searcherr and everyone who contributed.
I first bled the m/c with wifey putting great force on the pedal as 12Ounce suggested but I got an identical effect at both unions. Then I pulled off the m/c and started adjusting the pushrod. When I reassembled and drove a short distance around the yard I realized this was the issue.
A second adjustment and then the failing light got the better of me so I adjusted the pushrod way way out until it wouldn't allow the m/c to seat properly and then backed it off bit by bit until I was happy with the fit. Assembly and a quick test drive and I was one happy puppy.
This morning with a couple of site meetings I have covered 55 miles of mainly highway driving and the brakes are 80%+ of where I'd like to get to. A little bleeding to get some high quality fluid through and minor rear shoe adjustment and I'll be there.
In assessing the overall problem and fix I suspect that it's been the vacuum booster and not the original m/c that was at fault. The unit rattled internally as I was removing it and looked and felt the worse for wear.
I don't regret any of the expenditure or work I did as at 100k miles anything I replaced had given a good service life anyway and now we can hopefully have some trouble free time.
Sincere thanks to everyone who contributed, I never felt like I was in this on my own!
At 10yo the windstar can now look forward to a few years of gentle safe local driving with wifey and three kids to the library, park and grocery store and then one day in years to come I'll lead it to the big showroom in the sky.

HIP HIP HOORRAAAY!!! HIP HIP HOOORAAAY!!!
ITs MILLER TIME !!!


I'm about to adjust mine too Ulsterman (but on my car; been being lazy). I'm wondering though if I'm going to be able to bring it out as far as it needs to be without the lil cap-nut coming off the threads of the rod. I'm also going to look into a 7mm nut to put behind it so that I won't have to make this adjustment ever again.

There's plenty of adjustment on that pushrod Searcherrr, I brought it out over 3/4", you shouldn't require more than that. To cut short the trial and error I suggest simply screwing it out until the m/c will no longer seat properly then back it off gradually.

Good news indeed!

On adjusting the rear brakes, I use the following scheme:
1. With one rear wheel raised, the wheel still mounted to the drum ... the manual take-up is adjusted one "click".
2. The brake pedal is pressed/released several strokes.
3. The hand brake is pulled/released several strokes.
4. Turn the wheel by hand and repeat the above 3 steps .... until the wheel drags ever so slightly when turned.

Repeat for other rear wheel.

There's plenty of adjustment on that pushrod Searcherrr, I brought it out over 3/4", you shouldn't require more than that.


I guess on my car its a lot less than the van. On my car the push-rod cap-nut is only a tad longer than 3/8". Its like 3.25/8" long.


To cut short the trial and error I suggest simply screwing it out until the m/c will no longer seat properly then back it off gradually.

hehe - I know I know I write too much, but I had said that a few posts back just in a different way than you did. lol