Bumping sound

Hello, I have a 1998 Ford Winstar with 122,000 miles on it. I jsut changed rear brake shoes, drums and right side wheel cylinder. I bled the new wheel cylinder only, now when I apply the brakes, I hear a bumping sound out of the right rear. I switched the drums to see if maybe the drum was out of round. I still get a bumping sound out of the right side. Any thoughts? Thanks in advance.

Did you adjust the brake shoes after installation? I am wondering if the gap between the shoes and the drum is a bit excessive, and each application "slaps" the shoes against the drum. You might tighten them up a bit and see how that goes.

Thanks, I'll try that. Unless maybe I need to change the springs also. This is the 1st time I had a problem like this and I had this car for 5 years and 68,000 miles.

Even if the brake shoe is slapped against the drum, you hear the bumping sound , bump, bump, bump until the van actually stops. The sound slows as the van slows. Could it just be air in the line and the new wheel cylinder I installed is not holding the shoes out consistently while the brakes are applied?

I suppose that could be part of it. I'm a bit stumped. After re-reading your post I did notice that you only changed the right wheel cylinder. I was always told to do them in pairs and have done so. I don't know if that is contributing to the problem or not, but in the absence of any other help, you might try changing out the left one too and re-bleeding the system.

Good luck

OK, I only changed the right side wheel cylinder because the that was the only one leaking. The left one is not. The brakes and drums are brand new. Should I have bled all 4 wheels and not just the line I disconnected becasue of the leaking wheel cylinder? Thanks for all your help.

Please excuse the spelling and grammar.

Hi
I doubt that bleeding only the right side is an issue. I only offered the idea of changing both cylinders as that is what I have been taught. When I lived in VA, we had yearly inspection. My car had a bit of a leak on the right rear cylinder. The inspector told me to change it, and he said he wanted to see a new one on the opposite side as well, and he checked when I came back. My Dad had taught me that as well. Most would say the same for calipers, shoes, pads and anything else in the brake system. Can't say if it is based on evidence or part of an "old wives tale".
One other thing: I am a bit embarrassed to say, but I have failed to adequately tighten lug nuts after having a wheel off. A bit of vibration and noise clued me in to a problem, and when I went to investigate I found the lugs only "jack" tight.

Try bleeding all 4, although unlikely an air bubble may have traveled to a downstream cylinder. Be sure to follow the proper order for bleeding, start at the wheel furthest from the master cylinder and work back a wheel at a time to the one closest to the master cylinder. Check the manual for procedures related to the anti-lock brake system, the proportioning valve and the master cylinder itself.

Remember that the ABS makes a bumping noise when it engages. It may be interpreting the "lock up" or "grab" difference between the new cylinder and an older soft cylinder (one that has air or weak seals, etc.) as slippage and engaging. Thus the advice to change cylinders in pairs.

I just replaced both wheel cylinders on my '99 Taurus (same part#'s for the '01 Windstar too). Even though one side had a very slight leak, the other side did not, but was frozen and the pistons did not move in the bore. I would check the other side just to be sure. Also- did you pull the hub assembly and check the wheel bearings? You may have a bad bearing.

Thanks for all of the suggestions. Should the top of the brake shoes that fit
in the cups on the wheel cylinder be able to wiggle or fit snugly in the slot? I don't know if that has anything to do with it.