2006 roadster.

I have a front-end knocking which is clearly heard as 1 knock per wheel revolution. This happens on every drive, but you never know when it will begin. Today it happened around 20mph so I pulled over and stopped. When I resumed driving, the knock had stopped. The knock is quite loud; loud enough that most people would pull off the road to investigate.

Might be worthwhile to know I just replaced the rotors and pads. I thought I did a pretty good job and torqued everything correctly but I still had a local shop go behind me and check my work. They took it apart and put it back together and said everything looked perfect. They torqued the wheels to 98 lbft. I find it odd this starts right after a brake job but I also had a camshaft sensor go bad immediately afterwards also so it's not necessarily related.

Has anybody experienced something like this? I'm at the end of my rope with what this could be.

 

While it's almost impossible to identify 'noises' over the interwebs, it sounds like it's wheel/brake related since the noise is revolution dependent. What did the local shop say the noise was? Have you checked your wheel bearings?

 

Anti-rattle clips put back? Wrong pads? any number of things, take it down your self or get a trusted friend to do it.

 

Anti rattle clips were installed incorrectly. Have them re-check their work. Take the tech for a teat drive first. Unless you went to a brake shop. Those techs are basically McDonald's quality employees and shouldn't really even be called techs.

 

Thanks for the replies so far.


I'm having "the best mechanic in town" take a look tomorrow morning.

In the off-chance that someone on this forum might know what looks right and what looks fishy, I will post some pics I just went out and took. FYI, these are StopTech Street rotors and pads bought from Tirerack.com.

 

Outside of brake fitment/install issues, bad wheel bearing, something rubbing your rims (like improperly routed brake lines), or a really out of balance rim/tire, I can't think of anything else rotation related that could be causing the knocking sound up front. BUT, you may have a suspension knock/sound that could be conflated with the wheels rotating. Just to be sure, you've ruled out engine accessories? Like AC Compressor, Alternator, PS Pump?

If you've ruled out the brake/wheel assembly and engine accessories, then I suspect it's suspension related since it's not always there. You mentioned this happens on every drive, but will start randomly. Check out your compression rod bushings. These are known to fail and produce a knocking sound.
Cheers!
-Icer

 

Could this be because i greased the outside of the brake shims? I just read the entire brakes section of my Haynes manual just now and it indicates grease goes between the shim and back of the pad. I realize this is a facepalm moment and i admit full responsibility. So this weekend when i have time to address this, I'll remove all the grease on the outside and reinstall. See the orange in the pics?

As for your recommendations, if the aforementioned fix doesnt work ill check into those but the sound is clearly coming from the front wheels.

 

Hi Justin,

I always put a little caliper grease between the back of my pads and caliper fingers/pistons. This should not cause a problem, I do it to prevent high-frequency vibration or brake whine/squeal. Now the orange stuff looks like "CRC Brake Quiet" to me, not grease. Brake quiet hardens up like RTV and makes removal/cleanup a pain in the butt. I personally don't like to use it, and for most modern vehicles equipped with pad shims, it's not required.
Cheers!
-Icer

 

The orange lubricant is Permatex extreme brake parts lubricant. I suspect the problem is related to the brake grease outside the shims and/or the "ears" or tabs of the brake pads not fitting as well as they should. There is slop, and I can move the brake pads up and down within the bracket when using a flat head screwdriver. So, despite purchasing $400 in brake parts, I've purchased another set of front pads from a different manufacturer. Hope it makes a difference.

 

Hi Justin,

A little bit of play or movement of the pad ears laterally inside the caliper bracket is perfectly normal. This slight movement is immediately taken care of as soon as you apply brake pressure and won't happen again unless you change the rotational direction of your brake rotors (braking in reverse). My Brembo brakes do this the 1st time I brake in reverse and then again when I start moving forward. All you hear is a subtle click of the pads as they set in the bracket. This does not cause a repeat knocking sound.

I really don't think your brakes are the issue and I would hate to see you throw the parts canon at this without proper diagnosis.
Cheers!
-Icer