DLfpv

Hello, I recently purchased a ls400 from a used car dealer that had changed the pads and rotors on the car and the brakes were making a high pitched squealing sound so I decided to change the parts for higher quality components. I used toyota anti squeal shim kits 04945-50012 and 04946-50021, akebono pads, centric coated rotors, and permatex ceramic brake lubricant between the shims and pads. I bed the brakes in after install. for about 2 days they were quiet but are now very loud when lightly braking and getting louder every day. I am unsure what to try next.

LeX2K

How exactly did you do this? There is no specific break in procedure for pads unless the manufacturer specifically says so, and if they do I won't use their products or will ignore the procedure.

DLfpv

I did 4 moderately hard stops from 70 to 20, not super hard but a bit more then normal braking probably 30% of the way to lock up, then drove without coming to a complete stop until they cooled. I have done much more aggressive bed in procedures with other cars in the past and did not have any noise.

LeX2K

I personally think hammering the brakes when the pads are new is bad practice, the rotor to pad contact is not optimal at first it takes a bit of wear before there is ideal contact. What you're doing is stressing only part of the pad and rotor which creates hot spots and can glaze the pads. But some pad manufacturers feel different they insist on a specific procedure. If Akebono has a break in procedure I have not seen it, the paper that comes in box has basic info if it's there at all.

Either way pad noise is high frequency vibration because the pad is not making good contact with the rotor and/or the pad is vibrating in the caliper. Why did you use Toyota shims with the Akebono pads? Did the Akebono pads come with any shims? Did you service/lube the slide pins or at least check them?

400fanboy

I recently put akebono pads on my car - took 500 miles or so for the squeaking to stop. Used the included shims & lube. It was mostly light pressure slow speed that caused the squeak, but it eventually went away.

The fronts have always been tricky - they were squeaking really bad (Which is why I replaced them in the first place). Rotors were grooved like crazy. I haven't touched my rear brakes in 4 years since I bought my car, still tons of life left.

DLfpv

I replaced the single akebono shim with the 2 piece lexus part (stainless plate against pistons then typical rubbery shim between pad and stainless plate) because I had thought it would reduce the chances of something like this happening. I cleaned and lubed the rear slide pins, the front does not use a typical slide pin setup as it is a 1 piece 4 piston caliper where the pads slide out the back side of the caliper. I am pretty sure my noise is coming from the front.

DLfpv

I have done about 3-400 miles so far, I hope it just goes away on its own that would be nice.

RA40

iTrader: (6)

May check that the retaining pins in the front are straight and not bent. Clean any residual buildup on those and the caliper where those insert.

Superfast1

Brake bedding is a technique that's more applicable to high performance & racing than normal daily driving application. The idea here is to apply a thin, even layer of the brake material on the top surface of the brake rotors when they're brand new so when the brake is applied, having 2 surfaces with the same soft material will provide better braking power. Proper bedding toward the end is also very important as you don't want to leave the brake pad's footprint on the rotor's surfaces while they're extremely hot which will create high spot on the rotors & cause vibration at braking later on. That why it's highly recommended immediately right after bedding, the driver to keep on driving at normal speed without stopping to allow the rotors to cool down. Again, doing so will prevent high spot on the rotors & prolong the life of your brake. When it's time to do brake, I've always go through the bedding procedure on my high performance Vette & my Benz CL500 coupe but not so much on my other family vehicles. I have been doing this for years & have seen great benefits of doing it so it's a proven method.

In regards to your high pitch brake squeal, you've covered pretty much everything & appeared to have done it correctly so here's the last thing you should check: Take a close look at the brake's metal brackets that came w/ the brake pads, especially the ones that you installed into the brake's calipers. For the front brakes, take a look at the metal retainer clips. Make sure they're centered & the 2 guide pins are tapped all the way in from one side to the other. For the rear brakes, due to the tolerance stack up, one ear of the brackets may be sticking out a bit farther than the other ear & enough to make contact w/ the rotor(s) at braking so check there. I have had to modify the center slot to re-center the bracket and/or cutting the ear off on a few of them in the past. In some cases, I even had to re-use the old ones. Good luck in your finding.

YODAONE

Did brakes squeal before you installed replacement parts?

Unfamiliar with your aftermarket rotors..
are they by (small) chance drilled/slotted unidirectional?

Also, did you replace with OEM mounting clips?

Use new OEM brake pad retaining pins.

If regular rotors, then switch to OEM.

A lot of substandard aftermarket rotors out there.

Did you bleed entire system, including antilock brake solenoid?

JRF

My 2000 LS 400 has a brake squeal. I have taken the car back and they can't fix it. It is only when I first crank and after the first couple of brake applications. After that, it stops. Thinking it stops due to some type of metal expansion. I have no idea how to fix.