Stuck brake problem, after lots of new components, help me!!

[beast02er]

So i'm getting really frustrated. I replaced my front calipers, I replaced my flex hose line with SS lines, new pads, new fluid, to fix a problem where my pads were not returing, so the brakes were kinda on where I drove. So when first replaced all that stuff, it seemed to be fixed to me. Then a couple of weeks ago I was driving it and I noticed it was back to where the pads weren't returning and the brakes were pretty much on in the front. I could tell because of the resistance and the EXTREME heat of the rotors when I had hardly pushed the brakes on my own. So being up at school I couldn't work on my car, so I took it to a place and they told me my Master cylinder was bad, so I had them replace it with a new one.

Well I just got it back thursday and it stopped fine, so I was happy. I drove home (80miles) for the weekend, and had a semi scary moment when I pushed the pedal down and it seemed like it went to the floor, but then later it seemed to stop fine. So I was a bit skeptical about this and wanted to take it for a spin to test the brakes before I drove back up. I went to a stored and on the way home I noticed the brakes were STUCK again! And this time it was pretty bad. I mean I put the can in neatral from going 30mph down a hill and the car pretty much came to a stop!! Then I got home and the rotors were hot as hell, almost had a blue tint!

So I am stuck, I have no idea what could be wrong or what to do. I will obviously call the place up that worked on my car and ask for my money back, problem is I can't even get that car back up here if they want to check it out or try and fix it. I have no faith in people fixing my car when I pay them all that money and then it doesn't work.

Hope you can help me,

I'm stumpped!!!

Bryan

red73

[02jake]

check that there is play at the brake pedal--I had a beetle many years ago where I did not set the brake push rod clearance and the fluid could not return to the resevoir thereby causing the brakes to stay on. As the fluid got hotter it would expand and apply more presure on the rotors.

[Mike Self]

1. Didja confirm that all four pistons on each front caliper were actually moving--didja press 'em in with your fingers, a big pair of arc joint pliers etc? If they are all moving, then...

2. I'd start to suspect something sticking inside your Master Cylinder...

Just as an aside...when you had no brakes after your 80 mile trip, that was due to the fluid boiling in the calipers from frictional heat.

Oh...didja replace the rear brake hoses too? They clog up just like the front ones...

cheers

mike

[Guest Anonymous]

Check your hoses again, check your calipers. Sounds like you may have a frozen caliper. How about the line running from the booster to the intake manifold, is that there, is there a valve & is it going in the right direction?

Start with front calipers & rear hoses first then go to other things.

[Marty]

I would make sure the brake petal is releasing when you take your foot of it. Havning then stick is prety common and if both front calipers are getting hot your brakes are dragging or you have 2 new front caipers that are bad (unlikely) next time they heat up on you try to pull the brake petal back with your toe if it moves and the brakes release you'll need to expose the petal box and lube the bushings under there and then all the joints under booster.

[peteinjp]

But with the 2002 adjusting the pushrod just moves the brake pedal position does it not? I can't remember. Still good to check it.

[Zenon]

As others have said, the first suspect is the pedal linkange. Make sure it returns all the way and nothing is rusty or binding. Spray all pivots and joints liberally with grease.

Also, make sure the brake light switch is not preventing a full return: The linkage should not be resting on the metal body of the switch and there should still be about 1/8" or more of the plastic plunger visible in the "brakes off" position. If in doubt, temporarily remove the switch. The switch must be adjusted so that it only just turns off the brake lights when the pedal is at rest.

I have seen a case where the booster was always in effect, essentially lightly applying the brakes whenever the engine was on. Was tricky to diagnose since everything seemed perfect - all the wheels spun freely when the car was jacked up to check them (with the engine off, of course).

If you suspect that, try this:

With the engine off and the car on level ground, release handbrake and put it in neutral then see if the car will roll easily. If not, pump the brake pedal untill all the stored vacuum is out of the brake booster and try again.

If it rolls easily in the above scenario, then:

Start the engine and try rolling the car back and forth. If it is now harder to move, your brake booster is making the brakes come on a bit.

This could still be because the pedal linkage is binding and not returning to the fully off position (most likely cause), OR, the master cylinder piston-to-booster pushrod clearance is gone. In either case, the master cylinder will not be returning to its fully-off position and hydraulic pressure will not be fully relieved.

If you are absolutely certain that the linkage is allowing a full return, then check/adjust the pushrod-to-piston clearance. The spec is 0.5mm, adjustment is by means of shims at "mushroom head". Factory manual says measurement is to be done with "plastic gauge" which I assume actually means "Plastigauge" (a trade name) since there is no way to access the joint with a feeler gauge with the master cylinder installed. You might be able to loosen the master cylinder mount nuts a few turns first to see if that extra clearance makes a difference. If you loosen them too much, though, you will lose the vacuum seal between the MC and booster.

If the linkage and booster pushrod-to-MC piston gap is not the problem, it could be a bad servo valve in the booster itself which would necessitate replacement. New boosters are $$$$. Fortunately, almost any parts car will have a good one since they are pretty reliable units.

Hope this helps,

regards,

Zenon