Wrong master cylinder - should I worry?

You must have an incompatible piece of hardware somewhere. The calipers are fine if they match up, they only have one moving part and that year Cougar really had no other option for calipers, so if they fit, they're right.

So, between your power booster, master cylinder and proportioning valve, something is "not exactly". I always had my power boosters and masters rebuilt so I always got "mine" back. I had my '68 Mustang with the Kelsey Hayes disc brake set up done that way.

The bitchy thing about Cougars and other Mercury products is that if you don't get the EXACT match up with parts, you'll have headaches like yours. Often enough, parts were specific for ONE year only and that's it.

Do you still have your old power booster and master? If so, shell out a few $$ and get them rebuilt. If not, try to get some NOS parts that still have the Ford/Mercury part numbers on them. You may even find them aftermarket if you hit upon the right source. Is there a club in your area that might be able to help?

I'm also not sold that you have the correct proportioning valve. This alone would be the basis of your woes.

Bob

I agree - I know it is just one thing that isn't playing well with the others. As a last ditch effort I am going to put back in the old prop valve (this has been rebuilt and has new seals), remove the adjustable prop valve, and do a little concentrating on the rear drums (ie - make certain they are clean and get new shoes). The wheel cylinders and springs are all new. After that, she gets put away or sent away to a pro shop in hopes they can figure out the piece that doesn't play.

I do have my old MC, in fact we took it apart, cleaned it up well, and put it in just to see what would happen, and it reacted the same with the new and the old MC's).

The booster was sent back to the place where we got the new one from (West Coast Cougar Classics) for the deposit. I suppose I could call him and see if he still has it but I doubt it.

Thank you so very much for all of your help on this Bob. Your input has been what has kept me going and not giving up.

You can do the rear shoes if you want, just make sure they are adjusted and (the long shoe goes to the rear) about equal to each other. This will give you a better pedal. That's why the pedal will come up with a couple of pumps, which has nothing to do with air in the system. It will help overall.

Install the original proportioning valve and take out the adjustable one, just to simplify the equation. For laughs, see what the depth of the recess (for the rod) is in the old one, measure it and write it down for now. You can compare it later when you get up the nerve to take the "new" one out again.

Maybe your booster manufacturer can double check to see that you have the right part for the disc brake application. I doubt he'd have yours around still.

I don't mind helping you out, the problem is intriguing. I'd like to see you get it solved eventually. I've played with old Cougars (the car type), Mustangs, Fairlanes and Falcons quite a bit and never ran into something like you got there.

We'll get to the bottom of this yet!

Bob

hahaha... just an FYI - took the cougar out for a quick ride on halloween - the push rod is out too far. The brakes started to seize pretty bad by the time we limped it back into the driveway. Guess what I'm going to be doing tonight! hahahahahahahahaha.... Oh well, at least we know where "too far" is!

Interesting though, I replaced the check valve and now the pedal seems to want to grab or work well at the top end of the pedal and then fades????? Have to fix the push rod and take it out again so I can get a better idea of what it is doing now.

Hooray, something happened! You HAD to force it to get something out of it, now you KNOW where too far is. I agree that now you have to back the rod off a tad.

You do understand what happened, the brake fluid heats up and expands, locking up the brakes due to having insufficient free play. Go with an 1/8" to start.

I think you're close to a solution and it will be a totally different animal once you fine tune the rod. If you haven't done it, check the rear brake adjustment as this will help the pedal height.

Bob

Update on the brake saga of SATAN'S COUGAR

Ok, so I adjusted the push rod back about 1/8 inch and then proceeded to check the back brakes, just in case there might be something amiss, or contamination or whatever. Well..... Bwahahahahahaha! Here is what we found when we took off the drum.

http://i287.photobucket.com/albums/ll130/msrae_generalchaos/brakes%20on%20cougar/brakes035.jpg

Yep - the pad is actually BROKEN. There is an extra piece that was floating around in there - hmmmm. Think this could have been an issue?????:shakehead Keep in mind, we had these brakes completely apart and put in new wheel cylinders and springs etc - why we didn't get new shoes I don't know, but the old ones looked ok with pretty decent wear life on them. There was no damage to them when we had them apart the first time.

Either we have some of the worst brake luck in the world, or this car is just another Christine in the making. :grinno:

I think with the properly adjusted push rod, the new check valve, the new booster, the PROPER MC, the leaky line fixed at the prop valve, new pads, new shoes, new calipers, new lines, new wheel cylinders and another bleed - I might just have it......


:lol::lol::lol::lol::lol::lol::lol::lol: Yeah - I'm not holding my breath, but I am hopeful.

I can't see the picture at work, but my guess is that a piece of the brake shoe lining broke off. Old shoes get brittle and often a corner breaks off from taking the drum off and on.

Slap a new set of shoes on, adjust them up (do not bleed it, quit while you're ahead!!) and go for a ride.

Bob

I can't see the picture at work, but my guess is that a piece of the brake shoe lining broke off. Old shoes get brittle and often a corner breaks off from taking the drum off and on.

Slap a new set of shoes on, adjust them up (do not bleed it, quit while you're ahead!!) and go for a ride.

Bob

Well Bob, As usual you were right on. Yes, a piece had broken off. We have put on new shoes and I took it for a ride.

The brakes are still not right but they have "changed" through all of this. What I get now is a stiff pedal when the car is of (rock solid). A soft pedal when the car is on -which feels normal. What it does do however, is gives a good grab for the very first second when you hit the pedal, then it "fades" and you have to increase the pressure on the pedal until the brakes fully engage. If you drive for a bit without using the brake, it does the "grab first touch and fade" thing. If you continue to use the brakes, the first grab seems to go away and the brakes become progressively more difficult to get to engage.

My thoughts now are leaning toward vacuum - either the booster (which is new, but could possibly be defective), or just a bad vacuum somewhere.

Any thoughts? I know it can be really tough when you can't actually feel the pedal but I am hoping from the description you might have an idea.

Thanks again Bob.

My thoughts now are leaning toward vacuum - either the booster (which is new, but could possibly be defective), or just a bad vacuum somewhere.


I agree, that sounds like a vacuum supply problem.

In my experience, a few things can cause this. If the vacuum line going to the booster is under-sized, or if there is an under-sized fitting, a kink in the line or any other kind of partial obstruction or leak, your vacuum booster will 'fade away' exactly as you describe.

Also the vacuum source needs to be the manifold vacuum (the one that sucks most at idle) not the ported (distributor) vacuum.

If there is no obvious obstruction, install a vacuum gauge on the vacuum line for the brakes. Tee it in if you have to, and measure the vacuum strength that the brakes are getting. It should be at least 18 inches of vacuum at idle. It will drop as you step on the gas, that's normal...... any less vacuum can cause a problem like you describe. Poor vacuum can be a result of improper valve timing, leaking intake valves or a radical aftermarket camshaft.

If all this checks out then it may be a bad booster.

I agree, that sounds like a vacuum supply problem.

In my experience, a few things can cause this. If the vacuum line going to the booster is under-sized, or if there is an under-sized fitting, a kink in the line or any other kind of partial obstruction or leak, your vacuum booster will 'fade away' exactly as you describe.

Also the vacuum source needs to be the manifold vacuum (the one that sucks most at idle) not the ported (distributor) vacuum.

If there is no obvious obstruction, install a vacuum gauge on the vacuum line for the brakes. Tee it in if you have to, and measure the vacuum strength that the brakes are getting. It should be at least 18 inches of vacuum at idle. It will drop as you step on the gas, that's normal...... any less vacuum can cause a problem like you describe. Poor vacuum can be a result of improper valve timing, leaking intake valves or a radical aftermarket camshaft.

If all this checks out then it may be a bad booster.

Thanks MagicRat! I have the vacuum diagram (yeah, spaghetti bowl of tubes ACK!) and plan on tracing them as best I can. I will see about picking up a vacuum gauge (or I might be able to use the one from my self bleed kit, have to read the instructions again). I Also plan on replacing most of the lines since the rubber is old and it won't cost much to replace. A vacuum issue seems in line with the fact that my hidden headlight covers aren't really closing on their own any more either and that is run by vacuum as well. I couldn't find any hoses that seemed to be kinked or missing but I have not really delved into it deep yet.

I am hoping it is a hose because I am pretty sure the valve timing is ok, I'm not getting any ticking or knocking and the engine is running smooth and strong.

The acid test for a bad booster is: With the car off, pump the pedal until you exhaust all the vacuum in the booster, it should be very hard at that time. With your foot on the brake pedal, start the car. The pedal should drop very noticeably. That means the booster is probably good or has no gross leak.

To really rule out the booster, unplug the vacuum line and plug it, you really have no brake booster. Now go for a ride. If the hydraulics are really good, it will stop but you have to use more force. It should be consistent though.

Aside from that, go with what te MagicRat suggests.

Bob

well i been reading with you guys, and was wondering if you made any headway?

well i been reading with you guys, and was wondering if you made any headway?

Not yet Joe. Planning on attacking the vacuum hoses this weekend. Gotta fix my DD first (stupid water pump went out :crying:). I'll let you know what I find. Be a nice little B-day present to me if I could actually get if fixed this weekend :tongue:

Just a quick update. I plugged off the headlight vacuum hose and tried it again. The brakes are better. Still not quite right but I think they are good enough to pass inspection. I plan on tweeking it more and putting on the vacuum tester, just haven't been motivated as of late. I am just elated that I was able to get it out, drive it around and feel like I could actually feel like the brakes are safe.

Thanks to everyone for their help.

A special thanks Bob and Magic Rat for you unending confidence and fantastic help/suggestions. I owe you big time!

Couple Of tips for you:
Hook up a T with the vacuum gauge going inside and watch it when you hit the brakes, if it gets less that 15 or so you may have a blockage or booster may be bad.
Just beacause a part is new or rebuilt doesnt mean its good. I have had bad luck with rebuilt master cyls, Buy a New one. Rebuilt boosters are bad too sometimes.
Cheap or glazed brake pads will cause or magnify your problem, Use the Hawk street compound pads from summit, pep boys. They're great.
And the most likely - Check if your front calipers are reversed - Left will fit on the right side and vice-versa, but you will never be able to bleed correctly. Look at the bleeder valves, should be at the uppermost point on the caliper cylinder. Also brakes must be bled with vehicle level. Good luck!

Couple Of tips for you:
Hook up a T with the vacuum gauge going inside and watch it when you hit the brakes, if it gets less that 15 or so you may have a blockage or booster may be bad.
Just beacause a part is new or rebuilt doesnt mean its good. I have had bad luck with rebuilt master cyls, Buy a New one. Rebuilt boosters are bad too sometimes.
Cheap or glazed brake pads will cause or magnify your problem, Use the Hawk street compound pads from summit, pep boys. They're great.
And the most likely - Check if your front calipers are reversed - Left will fit on the right side and vice-versa, but you will never be able to bleed correctly. Look at the bleeder valves, should be at the uppermost point on the caliper cylinder. Also brakes must be bled with vehicle level. Good luck!

Thanks MustangMarty. I'll keep that in mind. I know the front calipers are not reversed. We have gone over that one a few times. I'm pretty sure it is vacuum at this point. It has been pretty bad weather here as of late so she is stuck in the garage, plus I have been working a lot on my DD right now so, as soon as I have that cleared up, and the weather again turns nice, I will once again be ravaging this site for help. :wink:

Well, I know it has been forever, but I thought I would just post up a little update on the brakes.

They seem to be working. I played around with a lot of the vacuum lines. Replaced hoses that looked like they needed it and still had some issues. However, I ended up having the carb tuned/rebuilt because it kept stalling. Well, not only did that help the vert run better, but it also seems to have almost completely solved the brake issues that were left. Although they still don't seem quite right, they work excellently. The only problem I have now is that they seem almost too touchy! :D

Thanks again for everyones help!

As Jed Clampett would say, "Welllll doggies!".

If you feel that it stops safely enough, so be it. Did you jack up the whole car and have someone try to spin a front and rear wheel when the brakes were applied?

Having the carb done over could solve a vacuum issue and make it stop better. Some power brake systems are touchier than others. If it were my car, I would change the check valve at the power booster to see if that made a difference. Unless it is already new.

Have you tried to block off the power booster line and drive it? I would be curious to see if it took away from the touchy condition.

Bob

Glad to read that the project is coming along. Sometimes, after replacing a master cylinder, the brakes are a bit touchy. Sometimes, this is due to an 'overboost situation due to a maladjusted power brake booster pushrod.

If you removed the master cylinder, you would see the end of the pushrod in the hole where the master goes. Turning it to move it outwards just a bit may fix the touchiness. However, I'm sure you are in no mood to work on the brakes anymore.... it's usually just fine to drive as-is.

BTW, what kind of carb is on this? If it's an Autolite 4bbl, you have, imo, one of the best carbs out there. They are great for smooth, seamless performance on a stock engine.

well i am glad to hear that, i was wondering how you made out, and the carb not producing enough vacum at times will play a big part on well it run or drive you nuts

As Jed Clampett would say, "Welllll doggies!".

If you feel that it stops safely enough, so be it. Did you jack up the whole car and have someone try to spin a front and rear wheel when the brakes were applied?

Having the carb done over could solve a vacuum issue and make it stop better. Some power brake systems are touchier than others. If it were my car, I would change the check valve at the power booster to see if that made a difference. Unless it is already new.

Have you tried to block off the power booster line and drive it? I would be curious to see if it took away from the touchy condition.

Bob

It definitely stops well enough to feel safe now.

Yeah, we tried the "spinning each wheel" trick at the start of all this. The brakes always worked well enough to stop each wheel from spinning under human power. :tongue:

I am still pretty convinced it is a vacuum issue somewhere, and being that the carb rebuild helped the problem substantially just verifies that more.

I have not tried blocking off the power booster. I might try that as well. Thank you again for all the help you gave me along the way.

I also replaced the check valve on the booster, that was also one of the first things we did.

Glad to read that the project is coming along. Sometimes, after replacing a master cylinder, the brakes are a bit touchy. Sometimes, this is due to an 'overboost situation due to a maladjusted power brake booster pushrod.

If you removed the master cylinder, you would see the end of the pushrod in the hole where the master goes. Turning it to move it outwards just a bit may fix the touchiness. However, I'm sure you are in no mood to work on the brakes anymore.... it's usually just fine to drive as-is.

BTW, what kind of carb is on this? If it's an Autolite 4bbl, you have, imo, one of the best carbs out there. They are great for smooth, seamless performance on a stock engine.

Hahahaha. In the previous posts it shows how many times I have already removed and replaced the master cylinder. I have adjusted and readjusted the push rod several times. Perhaps if I get bored enough I will take it out and adjust it a little.... but not now. :cwm27: It ain't broke enough to warrant that.

I wish it were the 4bbl. No, it is the stock 2bbl. I have been tempted to go out and get a fuel injection system for it, or perhaps just go with a nice 4bbl. Not sure if I can find an autolite, what are your thoughts on replacing it with a Holley?


well i am glad to hear that, i was wondering how you made out, and the carb not producing enough vacum at times will play a big part on well it run or drive you nuts

Absolutely!

Hahahaha. In the previous posts it shows how many times I have already removed and replaced the master cylinder. I have adjusted and readjusted the push rod several times. Perhaps if I get bored enough I will take it out and adjust it a little.... but not now. :cwm27: It ain't broke enough to warrant that.

I wish it were the 4bbl. No, it is the stock 2bbl. I have been tempted to go out and get a fuel injection system for it, or perhaps just go with a nice 4bbl. Not sure if I can find an autolite, what are your thoughts on replacing it with a Holley?

Okay, it's probably best to leave the brakes as-is. :)

As for the Holley..... what engine is in this, 302 or 351?

If you do go for a 4bbl, you will obviously need a new intake manifold.

A stock Ford iron 4bbl intake is okay, but the carburetor ports are a bit small and limit the variety of carbs that will fit.

An aftermarket aluminum manifold is much better, such as a "dual-plane" Edelbrock or Weiand model. There are lots of these used available at swap meets, so long as they are straight, not cracked etc. Ot they are available new for a reasonable dollar.


I am a big fan of Holley carbs. They are relatively simple, durable and extremely versatile. They can be tuned very easily to be used in a wide variety of situations.

They are not quite as sophisticated as most other 4 barrel carbs because their enrichment circuit (used to compensate for lower manifold vacuum) is relatively primitive compared to other cars, like the Rochester Quadrajet, Autolite etc. But they are so easy to tune that one can work around this.

http://www.holley.com

Holley has made literally hundreds of distinct carb models, based on 5 basic designs.

These designs are:

The 4150 and 4160 design.
-These are 'square-bore' models, where alll 4 barrels are the same diameter.
The 4150 and 4160 differ only in the way the fuel metering is set up for the secondary barrels. The 4150 is easier to adjust the fuel mixture for the secondaries, but is slightly more expensive to buy.
They have been made in many sizes from 390 CFM to 850 CFM.

The 4165/4175 :
This is a 'spread-bore' design, there the primary barrels are smaller than the secondary barrels, similar to a Quardajet and Autolite carb. The idea is that they will give better fuel economy for ordinary on-road driving. But their throttle response is not as linear as a square-bore design. When you open the secondaries, you get a more sudden power increase than a square-bore. This is fine fo rthe street, but performance/racing applications favour the 'squarebore' design.
They have been made in sizes from 650 to 750 CFM

2300 design:
This is a 2-barrel carb, its pretty much identical to a 4150, but without the secondary barrels. They come in 350 and 500 cfm.

The 4500 "Dominator" design:
Huge race-only carb, 1050 or 1150 cfm. Not for street use.

The 4360 design:
Strange-looking carb intended as a bolt-on replacement for the Rochester Quadrajet. It is not based on the normal 'modular' Holley design and is not very popular, and typically are rated at 450 CFM.

The first two designs shown above are the most common and the ones most often used. They can be bought with side-hung or center-hung floar bowls. The side-hung are cheaper and better for off-road use. The center-hung is better for street use with lots of high-speed turns. But for most regular sue, yo uwill not notice a difference.

These designs can use vacuum or mechanical secondaries. Vacuum is best for street use. The mechanical secondaries (often called "double-pumpers" due to their use of 2 accelerator pumps) generally are better for high-rpm racing.

You can get single-feed or dual-feed fuel inlets..... (dual is more useful for racing).... and mechanical or electric chokes. Electric chokes are more convenient but a bit more money.

So, what carb would I recommend for you?

For a stock 302 V8 or a 351 Windsor, I would suggest a Holley #1850 carb. This is a model 4160 carb, 600 CFM (cubic feet per minute), with vacuum secondaries. It's a perfect unit for a small block stock engine, or on ewith mild mods like headers, exhaust, mild cam etc.


You might want to get the electric choke option for this carb. It's more convenient and not much more money than a manual-choke model.

It is Holleys most popular 4bbl for good reason, and is quite inexpensive.

However, virtually all new Holleys seem to be jetted a bit rich for an all-stock 302. They will run great right out of the box, but might need a bit of leaning-out.

If you have exhaust headers on a 302, or have a 351 V8, the Holley jetting should be spot on.

But Holleys are extremely easy to tune. Slightly leaner jets are easy to get and easy to install.

BTW you will get people who claim Holley carbs are not good or use too much fuel etc. Imho, these people simply have selected the wrong carb, or do not know how to set it up.
For example, they may have a mild small block V8 but insist on getting a full-on race carb, like a huge 850 cfm double-pump carb then wonder why it does not work very well.
When you pick the right Holley for the job and set it up properly, they are superb.

Okay, it's probably best to leave the brakes as-is. :)

As for the Holley..... what engine is in this, 302 or 351?

If you do go for a 4bbl, you will obviously need a new intake manifold.

A stock Ford iron 4bbl intake is okay, but the carburetor ports are a bit small and limit the variety of carbs that will fit.

An aftermarket aluminum manifold is much better, such as a "dual-plane" Edelbrock or Weiand model. There are lots of these used available at swap meets, so long as they are straight, not cracked etc. Ot they are available new for a reasonable dollar.


I am a big fan of Holley carbs. They are relatively simple, durable and extremely versatile. They can be tuned very easily to be used in a wide variety of situations.

They are not quite as sophisticated as most other 4 barrel carbs because their enrichment circuit (used to compensate for lower manifold vacuum) is relatively primitive compared to other cars, like the Rochester Quadrajet, Autolite etc. But they are so easy to tune that one can work around this.

http://www.holley.com

Holley has made literally hundreds of distinct carb models, based on 5 basic designs.

These designs are:

The 4150 and 4160 design.
-These are 'square-bore' models, where alll 4 barrels are the same diameter.
The 4150 and 4160 differ only in the way the fuel metering is set up for the secondary barrels. The 4150 is easier to adjust the fuel mixture for the secondaries, but is slightly more expensive to buy.
They have been made in many sizes from 390 CFM to 850 CFM.

The 4165/4175 :
This is a 'spread-bore' design, there the primary barrels are smaller than the secondary barrels, similar to a Quardajet and Autolite carb. The idea is that they will give better fuel economy for ordinary on-road driving. But their throttle response is not as linear as a square-bore design. When you open the secondaries, you get a more sudden power increase than a square-bore. This is fine fo rthe street, but performance/racing applications favour the 'squarebore' design.
They have been made in sizes from 650 to 750 CFM

2300 design:
This is a 2-barrel carb, its pretty much identical to a 4150, but without the secondary barrels. They come in 350 and 500 cfm.

The 4500 "Dominator" design:
Huge race-only carb, 1050 or 1150 cfm. Not for street use.

The 4360 design:
Strange-looking carb intended as a bolt-on replacement for the Rochester Quadrajet. It is not based on the normal 'modular' Holley design and is not very popular, and typically are rated at 450 CFM.

The first two designs shown above are the most common and the ones most often used. They can be bought with side-hung or center-hung floar bowls. The side-hung are cheaper and better for off-road use. The center-hung is better for street use with lots of high-speed turns. But for most regular sue, yo uwill not notice a difference.

These designs can use vacuum or mechanical secondaries. Vacuum is best for street use. The mechanical secondaries (often called "double-pumpers" due to their use of 2 accelerator pumps) generally are better for high-rpm racing.

You can get single-feed or dual-feed fuel inlets..... (dual is more useful for racing).... and mechanical or electric chokes. Electric chokes are more convenient but a bit more money.

So, what carb would I recommend for you?

For a stock 302 V8 or a 351 Windsor, I would suggest a Holley #1850 carb. This is a model 4160 carb, 600 CFM (cubic feet per minute), with vacuum secondaries. It's a perfect unit for a small block stock engine, or on ewith mild mods like headers, exhaust, mild cam etc.


You might want to get the electric choke option for this carb. It's more convenient and not much more money than a manual-choke model.

It is Holleys most popular 4bbl for good reason, and is quite inexpensive.

However, virtually all new Holleys seem to be jetted a bit rich for an all-stock 302. They will run great right out of the box, but might need a bit of leaning-out.

If you have exhaust headers on a 302, or have a 351 V8, the Holley jetting should be spot on.

But Holleys are extremely easy to tune. Slightly leaner jets are easy to get and easy to install.

BTW you will get people who claim Holley carbs are not good or use too much fuel etc. Imho, these people simply have selected the wrong carb, or do not know how to set it up.
For example, they may have a mild small block V8 but insist on getting a full-on race carb, like a huge 850 cfm double-pump carb then wonder why it does not work very well.
When you pick the right Holley for the job and set it up properly, they are superb.

Wow! Thanks Magic Rat. A plethora of information in that post.

I have the 351 Windsor, and since it is a convertible, I am not planning on racing it. It is strictly my street baby. I was thinking the 4165/4175 would probably be the option I would consider. I was planing on getting an intake manifold too. I'm just waiting until I can afford it for now. I'm currently looking at 4 grand to repair the torque boxes and rocker panels (poor car was stored in a dirt floor garage for 14 years and the undercarraige shows it). So, more performance will just have to wait a bit I guess :mad: But I will definitely keep this in mind when the time comes. Thanks!