sonyman

For a little while I've been experiencing a pulsation in the brake pedal when braking, which I believe is being caused by excessive runout from the bit of reading I've been doing. I know that front brakes typically wear out before rear brakes which is why I'm planning on replacing the front rotors and pads. Also, I get a groan noise when I press on the brake pedal, audible when stopped or at very low speeds with the windows down. If I'm already stopped and I press harder, the noise is hear again.

Questions:
Is there a way to definitively say if it's the front or the rear brakes that need replacement, or should I replace all 4 corners as a matter of course?

I've been reading about the possible causes for brake pedal pulsation, and it seems that it is caused by excessive runout of either the rotor or the hub, or both. How can I pinpoint the culprit, or does one typically cause issues more often than the other? What else, if anything, could be responsible, or should I replace/repair?

Also, what is causing the groaning noise? If it's something that wouldn't be addressed by changing the pads then I'd like input so I can tackle it at the same time.

Lastly, is there any grease that goes on the pad/shim or anywhere that I'll need for installation? Is there anything I should know that will be helpful during installation? I will most likely be using OEM pads and rotors as I can pick them up for a decent price at work.

Thanks!

PureDrifter

iTrader: (10)

the way to tell which rotors are "warped" is to pinpoint the direction of the vibration. generally what i use is that if the steering wheel/dash vibrates or pulsates on braking then it is the FRONT rotors that need to be cut or replaced.
if the vibration/pulsation seems to be coming from the floor of the car (basically, you feel it coming up your ***), then it is the REAR rotors that are the problem.

check my UCF20 faq for a link to the rotor swap DIY

OEM pads are a fine idea but id strongly recommend looking at Brembo rotors, tirerack has them relatively cheaply

i had a similar issue with brake "groan" and pinpointed it to worn strut bars, its a precursor of the dreaded strut bar "thump". best bet is to replace the strut bar bushings (in the front, thats normally where they go bad first) with OEM bushings (~$30-35/each+install labor).

sonyman

So is it acceptable to only change the front brakes then? I'm thinking it is but I thought I'd ask to be sure. When I hit the brakes, the whole car pulsates forward to back, and I also feel it in the brake pedal. I feel nothing in the seat or steering wheel specifically. Also, I'll have to double check but I think I can get the rotors as cheap as if not cheaper than the Brembo rotors. Lastly, was your groan noise also present when stopped, and pressing harder on the brakes? I already had my caster arms replaced, which I am not sure is the same part with a different name. TIA!

PureDrifter

iTrader: (10)

you dont have to change the rotors, you can just have them cut/refinished for no more than $10/rotor at ur local shop/napa/etc...

you can change the front and back each axle at a time or all at once.

my ls had the exact same symptoms as you but it was totalled before i ever replaced the strut bars so im not sure if it will solve the problem in your case.

sonyman

Well I *could* have them cut but in order to compensate for runout (if there is runout) I would need to take the car somewhere where the rotors can be cut on the car. I suppose it wouldn't be a bad idea to take them to Napa but I don't want to have to take them off again if they still feel bad.

PureDrifter

iTrader: (10)

well ive never had a rotor cut improperly

good luck and make sure u post up what u eventually do.

sonyman

Will do. Maybe some pictures too if I'm feeling up to it. I appreciate your responses.

PureDrifter

iTrader: (10)

np have fun