95 Windstar,brakes dragging

I'm working on a 95 Windstar with about 180,000 miles on it,the left front brake is dragging after applying the brakes a few times.

My initial diagnosis was a collapsed flex line for that caliper,I opened the bleeder on that caliper and got a few drops of pressurized fluid out and the caliper released,replaced the flex line and still had the same problem.

At this point I'm thinking it's a problem with the ABS pump,but I would appreciate any comments on other possible problems.

Note: this is a mid 95 model,production date 6/95 with 4 wheel ABS.

The most likely cause is a sticky or seized piston at the calipers. Have your caliper(s) been replaced?

What about the sliding surfaces between the ends of the pad and the frame of the brake holder (for lack of the proper term)

I'm working on a 95 Windstar with about 180,000 miles on it,the left front brake is dragging after applying the brakes a few times.

My initial diagnosis was a collapsed flex line for that caliper,I opened the bleeder on that caliper and got a few drops of pressurized fluid out and the caliper released,replaced the flex line and still had the same problem.

At this point I'm thinking it's a problem with the ABS pump,but I would appreciate any comments on other possible problems.

Note: this is a mid 95 model,production date 6/95 with 4 wheel ABS.

Hello

:Edit: Keven I just *REREAD* your post and I believe I steered you in the wrong direction. This does sound like a bad master cylinder. I missed (overlooked) the part
of your post about the PSI fluid when bleeder was opened. Sorry.

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I would look at the caliper piston and the slides. I bet both are sticking. If one side is giving you trouble the other isn't far behind. I would replace both calipers and clean up the slide pins and lube them with a synthetic brake grease.

I had a 94 Caravan that both front brakes were locking up to the point that the previous owner burnt the rubber parts located around the brakes. (ball joint seals....) The problem was the master cylinder not allowing fluid out of the calipers. It was fine when I had it up on jackstands in the driveway. The smoke was rolling when I took it out for a drive!

I'm not saying that your problem is your master cylinder....I just felt it was a good time to share the story.

Regards

Dan

Thanks for the replies,I will check the caliper and slides for seizing tomorrow and let you guys know if that resolves the problem.

Not to be argumentative,but I don't see how these problems could cause pressure to be maintained in the piston with a free floating rotor and the wheel off,but I WILL check them,thanks again.

Kev413 -

Well - if the piston is sticking (and I have seen some *very* sticky caliper pistons), it can hang onto some pressure, even with the wheel off. And you won't get much fluid out of the bleeder in this situation: Recall that brake fluid isn't compressible; as soon as just a little fluid is released, pressure drops off right away.

Update,calipers have been replaced with new ones,I also cleaned the pin bores out and lubricated the slides/pins,problem still present,any other ideas?

Kev413 -

Wow - this is getting mysterious.

Let's back up just a little, and try a few specific tests:

- If you jack up both front wheels, apply and release the brake pedal and then try to rotate each wheel by hand, does this confirm that the front left wheel sticks and the front right wheel does not? You should be able to pretty easily turn each wheel (tranny will need to be in neutral). Normally, you'll feel a little bit of drag, but you should be able to turn each wheel without too much trouble. Is the orignal symptom (one wheel sticking, the other not) still present?

- Does this problem occur at the *first* application of the service brake, or does it take several applications? With the front of the van still in the air, do the symptoms differ when applying the brakes without the engine running vs. with the engin running (to check on how the brake booster might be affecting this)?

- When you bled the brakes after replacing other components, was the brake fluid unusually dirty, or have evidence of internal rust?

If the above tests confirm the original symptoms (front left brakes sticks; front right does not; presume rear brakes are fine), I'm leaning toward your original theory: The ABS pump unit appears to be the only item that hasn't been addressed yet that could cause this kind of symptom. I don't particularly like this diagnosis: I'm not terribly familiar with the internals of an ABS pump unit, but I do know that they're pricey.

Anyone else have further thoughts?

This might be a good one to post over on flatratetech as there are Ford mechanics over there.

I wonder if the proportioning valve could somehow figure into this?

The ABS unit is supposed to release the brakes during wheel lockup.....otherwise, it is not supposed to do anything.

But then.....a master cylinder is much cheaper than a ABS unit......so I would naturally lean that way....but it seems more likely that the master cylinder or the valve than the ABS.
Master cylinder, why not one of the rear wheels?....unless you have rear drum brakes that are less sensitive to this....or slightly out of adjustment?, or just not noticeable enough as compared to the front one?
But I am no brake specialist.

I haven't checked the details of exactly how the proportioning valve is configured for the Windstar - but the "one side on the front drags, the other doesn't" symptom still bugs me. I don't know of a master cylinder failure that would cause that symptom - but, as you, I'm a DIY brake enthusiast, but hardly an expert.

Thanks guys,so far I haven't noticed this problem untill the van has been driven and the brakes applied fairly hard a couple of times IE:quik stops from highway speeds.The left front is the only one affected,all others are free.

The proportioning valve is a good theory,from what I remember the ABS pump does have 8 lines hooked up to it,which would mean 4 from the proportioning valve and 4 to the brakes.
EDIT:there are 6 lines to the ABS pump,2 from the master cylinder and 4 to the wheels,no proportioning valve found,it apparently uses the ABS as a proportioning valve.

Your right wiswind,the ABS should only release pressure,not apply it.

As far as the master cylinder or booster,I can't see how either of these would hold pressure on one wheel only,the master cylinder only has 2 lines coming off it,one for the front and one for the rear.

The brake fluid was fairly clean,a bit discolored,but not filthy,and no particles in it that I noticed.I did pressure bleed the system untill I got clear fluid from all wheels when I replaced the calipers by the way.

Thanks for the suggestion to post in flatratetech,going there now.

Sorry it's been so long since I replied,but I wanted to make sure the problem was fixed before I posted.After looking closely at the brake fluid I noticed it had a greenish color to it,also it appeared "separated" sort of like a oil and vinager dressing thats not blended well.Some sort of contamination,not sure what it was.

On closer inspection of the front brakes I noticed the right front rotor was discolored a little from heat,so apparently it was dragging also but was releasing before I could jack it up and check it.

After seeing this I took the master cylinder off and disassembled it,the cups in it were swollen and distorted,I replaced the cylinder and flushed the entire system again with a pressure bleeder untill I got clear fluid from all wheels.Problem was fixed.I just rechecked this van yesterday,after a week of driving,and it's still not dragging.

Thanks everyone for the suggestions.

Kev413 -

Thanks for checking back in. Glad to hear the problem has been solved. That was certainly an interesting set of symptoms.