New brake job knocking sound... Help

[kanyewest]

Hey guys, first time posting and i need some help. I have a 2009 Camry base model 4 cylinder. I had all 4 rotors resurfaced but only replaced the rear pads. The front ones still had quite some "meat" left. While testing them out after the install i hear a knocking sound while braking but only right before the car comes to a stop. Need help please...

[Glenn8963]

the pads may be loose, the calipers may not be tightened, the inside of the rotors should have been free of all rust and debris, so that it sits flush on the hub. if the inside surface is not clean, then when the wheels are put back on and tightened, the rotors will NOT be sitting properly, this will in effect push back the pads away from the rotors.

i would disassemble it and check for things to be clean and properly mounted.

[kanyewest]

Ok so i took it all apart and cleaned absolutely everything. I made sure nothing was loose...still hear the knocking sound.

[Glenn8963]

the pads can be loose inside of the calipers, was any spring clips removed..??? also, did you reapply any liquid/grease sound deadening on the backing plates of the old pads? they can still be loose inside of the caliper mount.

the only other thing i can think of asking you is, "how did you push back the rear piston"..??

did you use a C-clamp, or a type of special socket that like screws in the rear piston..??

then, did you open up the bleeder screw at the caliper before you did this..?? because if you pushed back all that fluid into the master cylinder, and you have ABS brakes, you may have done some damage to the ABS system. that knocking sound could be the ABS system trying to release itself for normal braking.

[kanyewest]

I opened the break fluid reservoir cap (under the hood) then i used one of the old pads to push the piston back with my hands.
The rear pads did not have any spring or clips to be removed besides the wear indicator.
The prostop ceramic pads i bought, come with the backing plates.

[Glenn8963]

Originally Posted by kanyewest

I opened the break fluid reservoir cap (under the hood) then i used one of the old pads to push the piston back with my hands.
The rear pads did not have any spring or clips to be removed besides the wear indicator.
The prostop ceramic pads i bought, come with the backing plates.

ok, the correct procedure for pushing the piston back into the caliper, with ABS brakes, which i am sure your car has, is to loosen the bleeder screw then push back the piston. the old fluid will come out of the bleeder screw. when the piston is all the way back inside, then you tighten up the bleeder screw. what you may have done was mess up the ABS system, because you forced the fluid to go back through the ABS control block.

i will have to do some checking myself on how to correct this knocking sound, but you can google it as well, and we can get back here in a bit.

[Glenn8963]

here is at least one link to a site that also recommends opening up the bleeder screws before you push back the piston..

http://autorepair.about.com/library/a/1i/bl836i.htm

and another

http://www.ehow.com/how_7592259_chan...bs-system.html

[Donald E. George]

Did Toyota stop using the pad suppor plates on newer models? I went through all the calipers on my 04 this summer and replaced all the pad support plates and pin grommets. Look up Toyota Pars East and look at their illustrations for brakes for your model year and see if the pad support plates are still in use.

[kanyewest]

Update: the day after i installed, it rained after that the sound went away, it brakes awesomely... Thanks for the help

[Glenn8963]

well that certainly is a new one on me...some rain...sound goes away...

oh well...if it comes back, let us know, we can go from that point.

good luck, see ya later.