Rear brakes pulsating after replacement

[Topcga]

Recently replaced the rear drum brakes on my 2000 Windstar and they immediately started pulsating (no prior problems). The wheel cylinders were fine (not replaced) and the brakes were bled with no air found in the system and clean brake fluid throughout. Hubs and bearings look good - not bent, loose, or rough.

Thought the new drums were out of round so replaced them with more new ones - same problem. Then figured it was the cheaper aftermarket parts I got, so just replaced everything with brand new Ford Motorcraft parts - same problem.

The pulsation happens under all braking conditions. I have isolated it to the rear brakes because it happens when applying the parking brake (which is also how I know it is not the ABS activating). I have also recently had an alignment and wheel balance done, so that cannot be the problem.

Anyone else had this problem? What can cause it? I am stumped...

[12Ounce]

You have air in the system quite likely.

[Topcga]

Originally Posted by 12Ounce

You have air in the system quite likely.

System was bled and no air was present. Also, the problem happens when using only the parking brake (cable-operated). How could air be the problem?

Thanks for the reply!

[Topcga]

Originally Posted by 12Ounce

You have air in the system quite likely.

I am going to try and bleed the brakes again and see if that is the problem. I guess I can see how air in the wheel cylinder could cause the shoe to be able to vibrate on and off the drum surface as the brake is applied, even if the parking brake lever is actually applying the pressure.

Given that I already bled the brakes at the time, I am doubtful this will resolve the issue, but it is a good idea.

I will report back what I find.

Thanks!

[Topcga]

Originally Posted by Topcga

I am going to try and bleed the brakes again and see if that is the problem. I guess I can see how air in the wheel cylinder could cause the shoe to be able to vibrate on and off the drum surface as the brake is applied, even if the parking brake lever is actually applying the pressure.

Given that I already bled the brakes at the time, I am doubtful this will resolve the issue, but it is a good idea.

I will report back what I find.

Thanks!

UPDATE: Re-bled the rear brakes and there is no change. Brakes still pulsate.

[wiswind]

I had a similar problem.....van shook over 45mph.....was the brake drums........but you have already addressed that.
One other thing might be how the drums are secured.......maybe try removing each tire and then see if maybe 1 drum is very slightly crooked.......maybe hung up somehow.
Would have to be very slight....otherwise you would feel it just driving.

Another thing that comes to mind....at least it was true for my '96 Windstar.....the rear wheel bearings should be cleaned and re-packed now and then.
I prefered to have that done for me....but one can do it on their own.
They can develop a little extra play when low on grease.

Something with the rust ridge that develops on the inside edge of the brake drum could cause this....but that does NOT apply to this particular situation....because new drums have not rusted yet.

[northern piper]

ok, so the first thing I'd do (after all the stuff you have done which would normally be "first") is put a pair of pinch pliers onto one of the brake lines to stop the flow of the brake fluid to that wheel cylinder. Now, carefully, go for a drive and put your foot on the brake. If the pulsation continues, switch sides and try again. Assuming that you can close off the side that the pulsation is coming from you'll at least be able to narrow down where the problem is. Could this problem be on both? Yep. If nothing happens, that's likely the case.

Bleeding brakes does sometimes take a few times so don't be surprised about that. Another thing you can look at is how are the new shoes wearing. I've made it common practice to "arc" the new shoes with a fairly aggressive file that I have knocking off the leading and trailing edge. This will naturally happen with use during the first 50 miles or so and your pulsation may just solve itself. Between the hose clamping diagnosis, extra bleeding and arcing, you should be able to remove the pulse..

[zra4ok]

Hello topcga so did you solve this problem if yes how? Just have the same kind of problem with 01 windstar

[zra4ok]

[quote=Topcga;6979161]Recently replaced the rear drum brakes on my 2000 Windstar and they immediately started pulsating (no prior problems). The wheel cylinders were fine (not replaced) and the brakes were bled with no air found in the system and clean brake fluid throughout. Hubs and bearings look good - not bent, loose, or rough.

Thought the new drums were out of round so replaced them with more new ones - same problem. Then figured it was the cheaper aftermarket parts I got, so just replaced everything with brand new Ford Motorcraft parts - same problem.

The pulsation happens under all braking conditions. I have isolated it to the rear brakes because it happens when applying the parking brake (which is also how I know it is not the ABS activating). I have also recently had an alignment and wheel balance done, so that cannot be the problem.

Anyone else had this problem? What can cause it? I am stumped...[/QUOTE



Hi did u solve this problem? I've same kind of problem on my 01 windstar

[Topcga]

[quote=zra4ok;7050045]

Originally Posted by Topcga

Recently replaced the rear drum brakes on my 2000 Windstar and they immediately started pulsating (no prior problems). The wheel cylinders were fine (not replaced) and the brakes were bled with no air found in the system and clean brake fluid throughout. Hubs and bearings look good - not bent, loose, or rough.

Thought the new drums were out of round so replaced them with more new ones - same problem. Then figured it was the cheaper aftermarket parts I got, so just replaced everything with brand new Ford Motorcraft parts - same problem.

The pulsation happens under all braking conditions. I have isolated it to the rear brakes because it happens when applying the parking brake (which is also how I know it is not the ABS activating). I have also recently had an alignment and wheel balance done, so that cannot be the problem.

Anyone else had this problem? What can cause it? I am stumped...[/QUOTE



Hi did u solve this problem? I've same kind of problem on my 01 windstar

Sorry - no solution was ever found. I took the van to a brake shop and they found nothing wrong with the rear brakes although they admitted that the vibration was abnormal. They recommended replacing both rear wheel bearings, which I did. Guess what - same issue. Gave the van to my father-in-law and bought a 2012 Toyota Sienna Limited. No more problem.

[Topcga]

[quote=zra4ok;7050045]

Originally Posted by Topcga

Recently replaced the rear drum brakes on my 2000 Windstar and they immediately started pulsating (no prior problems). The wheel cylinders were fine (not replaced) and the brakes were bled with no air found in the system and clean brake fluid throughout. Hubs and bearings look good - not bent, loose, or rough.

Thought the new drums were out of round so replaced them with more new ones - same problem. Then figured it was the cheaper aftermarket parts I got, so just replaced everything with brand new Ford Motorcraft parts - same problem.

The pulsation happens under all braking conditions. I have isolated it to the rear brakes because it happens when applying the parking brake (which is also how I know it is not the ABS activating). I have also recently had an alignment and wheel balance done, so that cannot be the problem.

Anyone else had this problem? What can cause it? I am stumped...[/QUOTE



Hi did u solve this problem? I've same kind of problem on my 01 windstar

If it helps, I suspect it was one of the backing plates being slightly bent (possibly by me being a bit rough when removing the original drums). I never isolated which side it was coming from (using the method suggested by northern piper) but could have narrowed it down that way. Basically, that was the only part left that was not brand new and it was not going to be cheap or easy to replace, so I stopped there because the van needed to be replaced anyway. And the brake shop felt it was fine, so probably would have been another waste of money.

Sorry I can't give you a solution. Good luck!

[zra4ok]

[quote=Topcga;7050053]

Originally Posted by zra4ok

If it helps, I suspect it was one of the backing plates being slightly bent (possibly by me being a bit rough when removing the original drums). I never isolated which side it was coming from (using the method suggested by northern piper) but could have narrowed it down that way. Basically, that was the only part left that was not brand new and it was not going to be cheap or easy to replace, so I stopped there because the van needed to be replaced anyway. And the brake shop felt it was fine, so probably would have been another waste of money.

Sorry I can't give you a solution. Good luck!

Thanks for very prompt replay you saved bunch of my money and time I'm gonna check the baking plate tomorrow cuz I was a bit rough too:/ don't really want replace this van I need it for a couple more years only and have done a lot of work on it includes replacement of a/c compressor couple years ago and whole suspension and brakes )week ago
So anyway thank you and ill let you know if its the backing plate

[parkerb]

Originally Posted by Topcga

Thanks for very prompt replay you saved bunch of my money and time I'm gonna check the baking plate tomorrow cuz I was a bit rough too:/ don't really want replace this van I need it for a couple more years only and have done a lot of work on it includes replacement of a/c compressor couple years ago and whole suspension and brakes )week ago
So anyway thank you and ill let you know if its the backing plate

folks, you need to spend a bit more time using the search feature. then goto google. drum brakes can take up to 200 applications [stops] before they get seated and conform into shape. you can speed this process up by a) following northern piper's advice to arc the shoe followed by b) making a series of very hard stops. btdt.

[mdare35]

I'd bet the new drums were out of round. they needed to be turned. seems like all drums these days do this. I'd guess the plants in China just don't care. I had the same issue on my 2000 windstar. since my old drums weren't that worn I just put them back on and pulsing went completely away so I just took the new ones back. I recently replaced drum on a 2003 focus and it has pulsing, but wasn't real bad plus these are a pain to replace as the bearings are part of the drum, so I'm just putting up with and and it feels like over time they are getting rounded by wear.

[12Ounce]

Originally Posted by Topcga

Recently replaced the rear drum brakes on my 2000 Windstar and they immediately started pulsating (no prior problems). The wheel cylinders were fine (not replaced) and the brakes were bled with no air found in the system and clean brake fluid throughout. Hubs and bearings look good - not bent, loose, or rough.

Thought the new drums were out of round so replaced them with more new ones - same problem. Then figured it was the cheaper aftermarket parts I got, so just replaced everything with brand new Ford Motorcraft parts - same problem.

The pulsation happens under all braking conditions. I have isolated it to the rear brakes because it happens when applying the parking brake (which is also how I know it is not the ABS activating). I have also recently had an alignment and wheel balance done, so that cannot be the problem.

Anyone else had this problem? What can cause it? I am stumped...

I wish I had done a better job when I originally read your post. How did you determine the wheel cylinders were "fine"? At nearly 500k miles on our 1999, I would hazard to guess I have replaced the rear cylinders, in pairs, a half-dozen times. I use synthetic brake fluid, water proof Green Grease under cylinder dust cups and on backing plate lube points, and throughout the rest of the rear brake assembly. Even so, I find the pistons easy to "stick" inside the cylinder ... oh, they will still "work" .... just not as well as they are supposed to work.

My check? (1)Lift the shoes and all hardware away from backing plate, (2)with cylinder still in place, grasp the pistons with first finger and thumb,...can piston-pair easily be move fore-aft? If not, if stuck, replacement is likely needed. (When replacing cylinders new, I open up and lube thoroughly all internal parts ... filling end seals with grease, also.)

Good luck!