brake issues

[XxSiRhCy6PxX]

OK here is the situation. one afternoon i was cruising down the freeway and a truck in front of me dropped some debri from the load he was carrying. so then i braked hard and swerved away from it. close call, so as i took my exit and slowed down to the light, i notice that my brake pedal seem to kick back at me while it made some sound like it was grinding on something. It seemed like something was blocking the pads from braking or something because it didn't slow down like it used too anymore. got to my house and thought it might be alot of brake dust clogged or something so i washed it down but it still did the same. i checked all my pads and all of them are still in good shape. my dad noticed that the pistons weren't comming out at the same time and thought that was the problem so i went to autozone to get a brand new one and it still does the same thing. Deng this really sucks. i've searched but couldn't find any related threads. any ideas to what could be causing this problem? by the way it sounds like its commin from the front left

 

[XxSiRhCy6PxX]

Are the brake caliper pistons suppose to come out evenly at the same time?

 

[talontsi02]

when you say it felt like the brakes kicked back.. maybe its a problem with the antilock brakes kicking in? you already replaced the caliper? maybe you flucked up your rotors.. although i dont see how it could happen that fast

 

[KuZo]

Kick back constantly? Like it's pulsing? Maybe it could be a case of warped rotors, and brake fade. I know that when I'm at high speeds and need to slow down my rotors warp pretty damn bad and braking distance is increased a lot, but when they cool back down they are normal again.

Also if you lose vacuum in your master cylinder it will react like that. When you leave vacuum (bulid boost) the pedal becomes hard as a rock, essentially like you have no power assist brakes. But thats usually only noticeable when you're brake boosting or have been on it pretty hard and doesn't have time to build vacuum quickly. I'd check the vacuum hose to it anyhow, the one way valve might have broke.

 

[Drift_SM]

it might be a warped rotar. go have it checked out at a brake shop.

 

[Drift_SM]

thats what happend to my car and my friends wrx from braking hard and heating up the brakes.

 

[FORMONTOYA]

you did not warp a rotor. what probably happened is that when you stopped hard then let up off the brakes is that you took the pad coating off the rotors or added an uneven amount to them and now they pulsate on you. check out these articles to get up to speed on braking. then just re-bed your pads/rotors and they should be fine.


http://stoptech.com/technical/


jim

 

[XxSiRhCy6PxX]

the pulsating doesn't happen all the time. sometimes i can brake normally and i wont feel it. Then other times i would feel it even if i brake just a little. i don't feel it when i give it a quick kick and hold it for around 2 secs tho. this is weird.

 

[KuZo]

http://stoptech.com/technical/


jim

Good read

 

[TotalEclipse112]

Calipers are not supposed to apply evenly, there is a metering valve that sends hydraulc brake fulid pressure to the rear first to prevent lock up. If you don't have ABS then you have one of these. Sounds like the metering valve went, its sending fluid to the rear but not allowing enough fluid to the front, resulting in an uneven brake apply and a grinding noise. This would also cause the brake pedal to kick back at you, because the hydraulic system thinks it fully applyed so its kicking the pedal back.

 

[BudmannG]

OK, I just started this problem yesterday. But I didn't brake hard or anything like that. I installed a vacuum reserve canister. This is for the butterfly actuator on my cyclone intake. It is also making a load thumping noise everytime it pushes against my foot. Like it's hitting a brick or something.
The ABS light has been on sense I started driving it again. Took it to the dealer they told me 2 of my wheel sensors were bad. One of them they don't make anymore from the dealer. SO I have been searching boneyards for them no where. And on my way to the boneyards yesterday it starts this.
That is just a little bit of background on my situation. If anybody has any clue to what my problem is, Or can help me find some wheel sensors I would be greatfull.

 

[TotalEclipse112]

That sounds like a bad master cylinder. Did you hook up the brake booster line to the manifold correctly? Also did you hook up the vacum reserve canister to the master cylinder? Either way it sounds like a bad brake power assist. Is the pedal rock hard, like the brake pedal feels when the car isn't running, all the time, or just some of the time? Let me try and figure this one out.

 

[BudmannG]

This one is all the time now. I hooked the vacuum tank up the way the diagram shows.

 

[93anthracite]

does your car have ABS? you may also want to look into some kind of malfunction there. A rotor won't instantly "warp" in the sense that it will seperate pad and adhere to it. This is usually an event that happens over a period of time. In other words, if your pads are wearing evenly and the rotors have the same thickness all the way around (use a measuring caliper and check all the way around the rotors). I would move up from there. Start at the caliper, then check for any holes or wear on the lines (doesn't really seem to apply to your case). Then look into the master cylinder and the ABS solenoids/system.

 

[TotalEclipse112]

Double check and make sure the brake booster vacum line is hooked up properly. The rock hard pedal can be caused by the lack of vacum when braking. Also another possible thing to check is the mechanical linkage between the brake pedal and the master cylinder, it should be a rod that can be adjusted longer or shorter. Make sure that it is long enough to actuate the vacum valve in the master cylinder. But it defenitly sound like the problem is in the power assist area. Let me do some resarch and get back to you.

 

[XxSiRhCy6PxX]

i replaced my master cylinder and still the same problem Deng it


PS. my brake pedal pressure seems to be normal so i don't think its my brake booster.

 

[XxSiRhCy6PxX]

OK so i narrowed it down to be the ABS to be the problem because this morning i took off the ABS fuse to disable it and went for a test drive and everything seemed normal.

 

[TotalEclipse112]

If thats the case its probally the ABS control unit. Your brakes will sitll work just fine without it, you just won't have anti-lock brakes only standard brakes. If you can find a working ABS control unit somewhere and swap it you'll be just fine.

 

[BudmannG]

Hey guys, I just wanted to let you know I fixed my brake problem. If all else fails replace the rotors, All the rotors! Because you can warp the rears too. Yes, all of my rotors were warped. Thanks for your help.