Baptizer

Hello!
I'm hoping someone can help me with a really weird problem that I've been unable to identify. Recently, I changed the brakes on my 2006 Lexus GS300. Everything went real smooth with changing the front and back brakes.

When I took it for a test drive, I immediately noticed a SINGLE knock noise when I pushed on the brakes. Also, I noticed that sometimes when I got +50 mph, I'll hear the knocking noise in a repetitive fashion. If I gently apply pressure on the brakes, the knock noise stops. If I let go of the brake, the knock noise returns. It sounds like the knock noise is coming from the front-driver side area.

Does anyone have any ideas as to what the culprit could be? I've taken the wheel off a few times, took the brake pads off, put them back on, made sure the caliper screws were tight, etc.

Thanks!

alchemist

iTrader: (1)

If all bolts related to brake parts are tight, check your ball joints and tie rods.

Baptizer

Thanks for responding. Oh boy, I'm entering the danger-zone of car knowledge. Any pointers as to where these things are?

alchemist

iTrader: (1)

look at the write-up for my wife's RX330. I talk about and show pics of both:

https://www.clublexus.com/forums/rx-...ts-w-pics.html

Baptizer

Thanks for the great details. I check these things and everything checked out. Going to have a buddy look sometime this weekend as well. Any other thoughts?

alchemist

iTrader: (1)

Ok. Does the sound occur in reverse? Also on the side that makes noise pull the caliper pins and see if they are bent. Sounds like your pads are moving under are braking

ReyRey305

iTrader: (3)

Did you install the brake shim kit on ?

Baptizer

Thanks for the response guys! Forgot this past weekend was a holiday weekend so my wife had a bunch of other stuff planned for me. Ugh.

So the single-knock-noise doesn't occur when I go on reverse. Is that a good thing? Hah. I double checked and confirmed that I installed shims when I did the brake job (the old shims). Thanks again guys for the help!

canatto

Did you lube the back of the pads with the grease/compound on the back of the pads and between the back of the pads and the shims? Did you try setting the parking brake hard then releasing it? Does any of the rotors heat up after driving a while?