[David O'D]

in the last 50 miles I get grinding / scraping from the RF wheel under braking, in sync with wheel speed. At first I could barely hear it but this morning it became progressively louder. No noise once I'm off the pedal. The pads are new ATE and the car has 250 recent miles after sitting 7 months.

What could it be?

David OD
Laguna CA

 

[Alfajay]

David: That can happen from something as simple as a piece of road debris (AKA a pebble) getting stuck in the brake pad. Usually they will dislodge after several miles. But without disassembling and inspecting, it's hard to be certain what's going on.

 

[David O'D]

OK, thank you Jay. I'll check the wheel bearing for rumble, too. When I changed pads 7 months ago I had to free a sticking piston on the other side, but I doubt that's an issue here because the noise stops when I'm off the brakes.

David OD
Laguna CA

 

[David O'D]

Today I R & R'd the right front brake pads, and I think it's fixed. When removed both pads had rubber shreds from the piston dust boots (correct terminology?) stuck to their metal faces, and there were additional partially-attached rubber shreds protruding from both piston bores into the pad pockets. I scraped everything off the pads, pulled out the protruding shreds with needlenose, and reassembled with fresh red anti-rattle paste. No longer any noise.

The pads had less than 250 miles on them. On one of the pads, a shred was stuck in the contact patch of the piston, and one quadrant of the friction material looked less worn and rust-colored. Maybe the pads were being pushed unevenly because of a rubber shred where it didn't belong.

My understanding is that shredded dust boots are not significant, is that true?

David OD
Laguna CA

 

[0die]

I'm having a similar issue. Mine sounds like the classic wheel bearing noise. It comes occasionally after driving a few miles. When I turn away from the noisy side the sound gets worse (loading up the bearing) and turning into the noise it stops (bearing gets unloaded). Does not seem to be affected by if I'm braking or not.

So I remove the dust cap and find plenty of grease. But I removed the bearings, cleaned and repacked with lots of fresh grease. But I noted that one of the dust boots on the caliper piston was in shreads too. I didn't replace it but just put it all back together.

Still having the noise issue. It comes and goes. The last time I checked my wheels after parking. The one making the noise was very hot. Hot like from a stuck brake. I've not heard of a bad wheel bearing making the wheels that kinda hot.

So I gotta wonder if the failed boot has somehow allowed the piston to get debris or grit in and occasionally temporarily seize the piston?

 

[David O'D]

Hi Odie -

I couldn't guess in your case, but that certainly seems a possibility. I didn't have a hot wheel and my bearing is fine.

David OD
Laguna CA

 

[Gubi]

My understanding is that shredded dust boots are not significant, is that true?

Well, they keep water and dirt away from the piston and seals. So if they're not intact then that's not good for caliper life.

 

[radamm]

I personally would not run with any seal compromised in a brake system.