11 replies to this topic

[ericem]

Hi, Just did all 4 rotors and pads on the 94 SS. It seems like this is my issue with the shimmy and really bad fuel economy. After driving downtown the brakes smelled HORRIBLE. My dad checked out the temp of my brakes with a inferad gun and read the ONE wheel was 560F and the passenger side was around 100F. The rear brakes were only like 60 F. So I remember when I installed the brakes that driver side brake that is overheated actually moved pretty smooth and I greased the sliders very well, the sliders looked like brand new as well good boots etc. Used anti squeak on the back of the pads if that matters as well? When I bled my brakes, I did it in sequence with a brake bleeding tool. I remember with my wagon when I did this since I had help I just held down the brake, and my dad would close the bleed valve. This time I didn't do that had the bleeding hose in a tube which was submerged so no air could be introduced. Is this really neccesary? Anything else I should look at? Thanks guys!

[crash321]

Could be that the o-ring on the driver side caliper is causing the piston to stick and not return into the bore. Even though it really doesn't move much, it could hold that piston in position to cause your brakes to heat up like that. Replace the caliper.

[Rooster2]

Was the brake drag occurring somewhat before the new rotors and pads? If so, do new pads make it worse? Suspect that you have a bad brake caliper that is not releasing the pad pressure when you take your foot off the brake. Thus, you are effectively driving around with one brake still partially applied. That is why the rotor and caliper are so hot. I would think that you can feel the car "pull" to the left (driver side) when driving down the street.

I think if you replace the bad caliper your problem will be solved. You may also have to replace the brake pad that is prolly pretty well burned up as well.

[ericem]

Actually it probably was dragging, I remember sometimes it wouldn't really move to well, other times it was great. I am confused though, how do the brakes actually release? Tomorrow my dad will probably pull out the the caliper and see whats going on. If the piston is damaged is it pretty visible? This is what I noticed, if I stop lightly at a light and release the car rolls a tiny bit. If when stopped i push the brake hard and release the car will not roll and when you take off you can hear the brake grabbing. Should I just replace the O ring and gasket and keep going? I remember the gasket for the piston did not look so great. Didn't think it was very important seemed like it was just dried brake squeak flaking.

Edited by ericem, 16 February 2009 - 10:23 PM.

[crash321]

No it was not dragging really. I am confused though, how do the brakes actually release? Tomorrow my dad will probably pull out the the caliper and see whats going on. If the piston is damaged is it pretty visible? This is what I noticed, if I stop lightly at a light and release the car rolls a tiny bit. If when stopped i push the brake hard and release the car will not roll and when you take off you can hear the brake grabbing. Should I just replace the O ring and gasket and keep going? I remember the gasket for the piston did not look so great. Didn't think it was very important seemed like it was just dried brake squeak flaking.

When you apply the brakes your o-ring in the caliper, that is square in shape that resides in a groove, flexes outward with the piston somewhat. When you release the brakes, that o-ring returns to it normal "shape" Kind of likeyour return springs in a drum brake assembly. O rings eventually lose their elasticity and no longer perform the "return spring" function. Even though you can turn the wheel easily, it doesn't take much pressure to build heat in a brake assembly that is dragging. Just think of rubbing your hands together lightly for a period of time, you can move them easily, but it still builds heat. You can buy a rebuild kit but the agravation involve is not worth it. Rebuilt calipers are a good value and the easiest way to go. If that dust boot was torn in any way on the piston, then that is a sure sign that you should replace the caliper. Replace the caliper, that is the problem.

[Rooster2]

When you apply the brakes your o-ring in the caliper, that is square in shape that resides in a groove, flexes outward with the piston somewhat. When you release the brakes, that o-ring returns to it normal "shape" Kind of likeyour return springs in a drum brake assembly. O rings eventually lose their elasticity and no longer perform the "return spring" function. Even though you can turn the wheel easily, it doesn't take much pressure to build heat in a brake assembly that is dragging. Just think of rubbing your hands together lightly for a period of time, you can move them easily, but it still builds heat. You can buy a rebuild kit but the agravation involve is not worth it. Rebuilt calipers are a good value and the easiest way to go. If that dust boot was torn in any way on the piston, then that is a sure sign that you should replace the caliper. Replace the caliper, that is the problem.

HERE IS WHAT IS HAPPENING:

If the dust boot is torn or worn, rain water gets past the bad boot. Once inside the caliper, rust forms on the caliper bore. When the brake is applied, the piston pushes out, but take your foot off the brake, and the rust deposit prevents the piston from retracting, so the piston pressure stays on the brake pad. It is not worth trying to repair your caliper, buy a new one to solve your problem. BTDT

[ericem]

Ya got the caliper out. One piston is totally seized, broken seal. Rust indeed! Also found the slider to be stiff, and my disc looks messed, but it is straight now warped. Will get it spun and make sure it is perfectly smooth. The pads were fine though! So I think I found a few people locally who have a caliper. Should be fine I guess. This time I am going to bleed my brakes with atleast 2L of brake fluid to make sure there is no moisture in the other brakes. Thanks for the help guys!

[crash321]

Glad you got it fixed.

[ericem]

Oh ya forgot to ask do I need to remove the disc on the other side and make sure they are the exact same thickness or it won't really matter just one disc will obviously wear out faster?

[crash321]

Shouldn't matter. Driver side one will just have a shorter life if your had it turned. Personally, I never have been able to have any disk turned when I do a brake job because they were to thin.

[ericem]

See these brakes are brand new Less then 1000km on them lol. Amazingly the pads were perfectly fine! Just I notice the disc didn't has fine groves in it, I hope after I turn it, the disc is still fine. If not need a new disc I guess.

[crash321]

Disc should be fine, Whoever turns it should measure it to make sure it is safe to run before handing it back over to you. I know that NAPA and some others turn rotors and they will have the specs. Pads should be fine because they repeatly get extremely hot when you stop from highway speeds.