3rd Gen Brakes

[groober]

I am ready to have my 3rd set of rotors installed because of vibration. Owned since new, my original brakes worked perfectly until I had new brakes installed at 75,000. I am now at 107,000 and have had the rotors replaced twice already. Mechanics have looked at it and said the rears are adjusted and they find brake dust when inspecting the rear drums. Any suggestions to cure this vibration during braking?

[fenrisx]

Someone else can correct me if I'm wrong, but maybe you should also have your wheel bearings checked.

[MikeKMitchell]

I upgraded 4runner brakes to tundra (replaced rotors, caliper and pads). Brakes work great and have not developed the slight vibration on long downhill when old smaller rotors heated up. One problem I noticed is a loud rattle when going over a bump unless brake pads are slightly engaged to the rotor. Anti rattle springs installed correctly on calipers/pads ("W" shape when looking at caliper/pad from the front). I bought additional springs and installed on top AND bottom of pads ("M" shape on top and "W" shape on bottom). More force now on pads to keep them engaged with pisons. Also put "anit-squeal" blue goop on back of pads (slightly "cushions" interface between pistons and pads I guess). Clunk is gone. Not sure if additional spring or blue goop solved the problem but problem solved.

[MTL_4runner]

OP, sounds like either sticking calipers or bad wheel bearings.

[groober]

I was wondering how to test the load sensing proportional valve. I am still using my original rear shoes at 107,000.

[Seanz0rz]

what year is your 4runner? 96-98 doesn't have a proportioning valve.

i would say wheel bearings, make sure your calipers are at the correct torque. check for obvious cracks in the steering knuckles, play in the tie rod ends and rack.

[groober]

One tie rod end link replaced because of rust. No other issues in the steering especially after the end link replaced. Steering is like new tight. Rotors are simply warping, again. I've had the rear brakes and parking brake manually adjusted but remember, I still have my original rear shoes at 109,000. Everything else about this truck is almost flawless. I appreciate the heads up about the proportioning valve and I apologize for my lack of and appreciate the technical skill and knowledge most of you guys have.

[Seanz0rz]

i would flush the brake lines. it kind of sounds like your rear brakes are working, but not working well, putting alot of pressure on the fronts, and making them warp fast.

[MTL_4runner]

You might pull the drums off the rears to make sure they are working and haven't seized up for some reason.

1) remove drum
2) verify adjuster turns and hardware is in good shape
3) make sure wear plates are lubed
4) check for leaking axle seals
5) compress wheel cylinders
6) reinstall drums
7) adjust drums properly


Also make sure the fronts are operating up to par as well.

1) remove caliper
2) check calipers by compressing pistons with c-clamps
3) grind off any rust debris which prevents pad movement (calipers and pins)
4) reinstall caliper

Ideally you have a compressed air source and can make a homemade power bleeder for the lines as well.