New Rear Brakes and New Sounds Associated with Service

Hello all,

I have long used this site as an excellent source for information on my 2003 Toyota 4Runner Limited but have run into an issue that I cannot solve.

Mid summer this year, I replaced the rear brakes (pads and rotors) with Toyota OEM parts. This included new "anti-squeal" clips on the top and bottom of the pads and shims on the back of the pads. I followed the Haynes manual and used any techniques I learned during many pad/rotor services in the past while working at a few dealerships in high school (ie, not my first brake job).

I now have a very high frequency squeal from both sides of the vehicle for the first 2 or 3 stops (obviously until the components heat up and expand). Because of this, approximately 8 weeks ago I took the pads off the calipers and re-applied anti-seize grease on both sides of the shims. This did not take care of the issue, and I now have an extreme resonant frequency (similar to rotating a wet finger around the top of a crystal glass, but so loud the neighbors turn and look) coming from the passenger side "wheel assembly" (source unidentified).

Any ideas why the high frequency squeal and NEW extremely audible resonant frequency??? All suggestions welcome and greatly appreciated.

Thanks in advance!

Wheel bearing?? Totally unrelated to your brake job. Not uncommon for them to go as multiple people on here have had to replace them

Eskimochaos, thanks for the response. That is a good suggestion, but that raises the following questions:

1) Loud resonant frequency (LRF, i'm tired of typing it!), why only in reverse?
2) LRF only occurred after I pulled the calipers/pads the second time to add more anti-seize/high-temp brake grease to combat the squealing (used a c-clamp to push the pads together MAYBE 1/8").
3) Why no squeals/LRF with the old pads/rotors?!?

Last night I removed everything all the way down to the rotors. Backed off the parking brakes even further, sanded all pad contact surfaces to caliper mounting bracket, coated all pad contact services with high temp brake grease, and this morning, still LRF in reverse.

Are you aware of any signs of wear on the rotor/pads that would tell me a caliper is hanging up? Both recessed with the c-clamp without any issues.

Thanks again for suggestions!

IM having the same issue. taking it to a mechanic buddy right now. ill post outcome when i found out what it is.

I hate the squeal clips, but they also should have used anti-squeal grease in there... I'm guessing they did not.

Azt4r,

Any word from your "mechanic buddy"?

Does anyone know what the correct clearance should be for the parking brake shoes? Should they be just out of contact with the parking brake 'drum'?

Thanks!

For parking brake adjustment from the 2005 repair manual page 3728:
"(b) ...turn the adjuster and expand the shoes until the disk locks.
(c) Contract the shoe adjuster until the disk rotates smoothly.
STANDARD : RETURN 8 NOTCHES
(d) Check the shoe has no drag."

You may also have to check the park brake pedal also.

Hope that helps.

first think check for any metal flakes indicating squeelers hitting or holder shims hitting...

you should never have to c-clamp the pad together to get them in the holders.. i would re-clean the slide pins and the holder brackets.. if you think its the e-brake remove the rotor and see if you blew it apart by not adjusting it before removing the rotor.. and adjust it all the way down so they wolnt interfere and if the noise is still there then its a pad and rotor issue..

and at my dealer rear brakes pads dont come with new squeelers unless you got yzz pads from the dealer then just throw them out

Did you "break-in" the pads and rotors properly?

Steel409 said:

Are you aware of any signs of wear on the rotor/pads that would tell me a caliper is hanging up? Both recessed with the c-clamp without any issues.

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Okay, here's my $.02. I've had to track down brake issues, and although it is hard to determine the exact problem without hands-on, I'll give my best guess with the info you gave. (BTW, here is my tips post: http://www.toyota-4runner.org/4th-gen-t4rs/76992-brakes-frozen-maintenance-tips.html#post657265 )

I now have a very high frequency squeal from both sides of the vehicle for the first 2 or 3 stops

Click to expand...

This is a likely sign of the calipers and/or pads hanging up. They continue to rub a bit too hard against the rotor.

A few key points about this:

1. If you remove your calipers from the vehicle and disconnect the line, you should be able to push the calipers in by hand. It may take a very strong squeeze, but I do it. I use clamps to break them free if they are sticking a bit, but then they should move freely.

If not, check the dust boots on the piston. There shouldn't be any cracks or breaks.

I also like to run some fluid out the line and dump all the fluid out of the caliper when doing a "full" brake job (not necessarily every pad/rotor change, though it wouldn't hurt)

2. The pads should *NOT* be jammed into the brake housings. Look at the metal "liners" in the notches where the ears of the brake pads fit. The notches should be square with right angles, not bent or rounded.

A point here: DO NOT USE WEAREVER BRAKE PADS. Take a pair and look at the ears. They are NOT at right angles. EVERY one I have seen in the past few years has been rounded in the notch, causing them to hang up. I ground them to the correct shape for a while, then changed brands. And I like Advanced Auto.

If the notches are not square and open, remove the metal clip and chip out the rust. I use a chisle that I tap lightly. This is easier if you separate the two halves (Remember, we are talking REAR calipers. Do NOT separate the two halves of the hydralic section of the front calipers)

3. Have you removed the rotors? I suspect you got some rust and/or dirt in your parking brake and rotor interior. You do clean the INSIDE of the rear rotors with brake cleaner, too, before installing, right You can use an air hose to blow out junk. Check for broken springs and that the parking brake pads are centered about the wheel.

4. Make sure your parking brake pedal is returning all the way and still has a bit of tension when retracted. If not, you may have a cable or other component hanging up.

Hope this helps!

- JC