I just purchased a used GX470 with 37K and I just noticed a strange grinding sound from the rear while braking around 20 mph down. it only happens when I really apply the brakes. I took it into the dealer and they told me it was due ty my new wheels and lug nuts. The wheels are aftermarket forge tech rims make for this car, hub centric and made for lexus lug nuts ?? I also had these on my 2010 gx460 for 3 years with no issues. needless to say, I swapped out the wheels for the stock ones and I still have the grinding noise. I was told that the brakes are fine so I'm looking for ideas or solutions. I searches the forus and I really didn't see anyone else having this issue. Any information would be great. Thanks!

 

Have same sound on a 2005 gx470. Just replaced the rotors and pads on the rear (needed it badly on the left side ) but, STILL have loud, awful grinding sounds from the rear wheels/brakes. I am guessing it is the EMERGENCY brake???? Pull up handle never seems to engage. Maybe cable is broken? Or need to tighten up the star wheel?

ANyone know the answer?

 

Could be a tiny rock or pebble stuck in one of your pads... I’ve seen them embedded deep and causing this concern. I’d also check the inner and outer rear pads... a tech is prone to checking the outside pad with a mirror. But if you have a sticky caliper, one pad could look new and the other pad could be down to the backing plate.
Ive also seen “squealers” break off and get stuck in an area of the caliper that causes that grinding noise when breaking.

But in all reality... you just need to pull the rear tires and calipers, then check the pads and rotors for overheat marks or groves... any noise that’s consistent in the brakes will leave some form of markings on the pads or rotors. If the issue is brake related... that is.

 

MrJason,

I literally replaced the rotors and pads yesterday. (son drives the car) One of the rotors was so worn down, to almost paper plate thin because the brake pad was completely gone. The caliper was grinding the rotor down. Crazy & fortunate nothing bad happened.

99% sure I will replace the calipers today. it almost has 200k on the car, so might be due anyway.

 

Jaydog get a wheel off and check it out. It definitely sounds brake related. I had a frozen rear caliper on my 03 before. Let us know.

 

You may want to inspect the pads... both inner and outer. I’ve seen slightly sticky calipers cause pads to wear so unevenly that the outer pad looked new and the inner pad was worn to the backing plate.
Dont take a dealer era technicians word that the brakes are good.... they tend to look through the wheels at the outer pad only... it’s a product of the flat rate system(but that’s a whole different debate).

Snd yes.. something could have come apart in the e-brake portion of the rotor assembly. But that generally makes a noise all the time... not just when braking.

 

YEs, in my car, the sound was constant. The sound, however, is almost gone. Only when I turn does the sound come back. Doing slight & tight slalom type turns, you get the sound. When driving straight, the sound is no longer there. New pads and rotors wearing out the sound? ha ha?

 

Hopefully it's not something as stupid/silly and visible, as a slightly bent dust shield.

 

I’ve answered this question several times... but every time I come back to the post... I only see 2 comments.

 

Finally I’m now seeing the other comments.

If you just replaced everything.. make sure you didn’t install something wrong or have something get caught up in the parts you replaced.

Ive seen 20 year techs make stupid mistakes.. like installing a brake pad backwards.


Was the sound there prior prior to the brake job??

 

Thanks for the reply, I ended up purchasing a new GX460. So I guess I solved the problem