FINAL UPDATE: Powerstop Rear Brakes - Grinding

Good morning. Having previously upgraded my fronts, I finally completed the upgrades on the rear this weekend. This included rotors, calipers and pads (all Powerstop). I am experiencing a grinding noise bilaterally at speeds up to about 30-35 mph and then it appears to dissipate.

Here are some details:

• I cleaned up all surfaces, including a light sanding of the drum brake assemblies.
• Greased all appropriate surfaces of drum brake assemblies.
• No modification/alteration/grinding of the kit was required for fitment.
• I followed the Powerstop recommended break-in, exactly.
• This is noticed in forward and reverse.
• This is noticed when driving and braking.
• I've checked for rubbing of the backing plate against the rotors and found nothing.
• The brakes seem to be functioning perfectly.
• Dissipation at higher speed implies some kind of centrifugal force at play here.

Anyone have any ideas? I feel like my symptoms are slightly different than what my initial research on this site found since the grinding seems to dissappear at higher speed.

 

Yup.

There is a smaller backup plate to which the eeeeee-brake (Halloween) components are affixed. This plate has teh rolled edge and forms a labyrinth seal with teh rotor. I had rubbing issues after using my eeeeee-brake (Halloween) with the full stroke of the pedal. I think it flexed the plate because it started making noize (Flava Flav!) as you describe. You can't see the rubbing unless you unmount the rotor. I ended up cutting away teh offending plate after new rotors created a cacophony.

 

Good Monday post.

 

Thank you @hagrid - and RIP! You were a good man to Mr. Potter.

 

And a really good man to Ron Weasley's mom.

 

Thanks so much @hagrid! This was exactly the issue. I pulled both rear tires and confirmed the cacophony was limited to left side only. After pulling that rotor, it was evident there were two rub spots on the inner plate edge described by Hagrid. For me, the spots were about 8:00 and 2:00. I wondered briefly about why those opposing positions but only briefly.

The spots appeared to be previous damage from the first rotor replacement at 55k. The tighter tolerances in the Powerstop rotors simply made it obvious that two spots were protruding slightly.

The solution was a combination of tapping those two spots inward (i) and using a grinder. I also ground the inner rim of the perimeter of the rotor slightly. I did this over three passes, trying to remove as little as possible each time. I'd remount the rotor after each grinding pass until I was left with almost no sound. That remaining sound dissipated after any residual high spot was ground off over the course of a 10 mile road trip under 40 MPH.

 

HA HA! YEEEEAH BOI!!

Bass! How low can you go?
Death row? What a brother know.
One again, back is the incredible,
Rhyme animal,
The un-can-able, D!
Public Enemy number 1.
Five-oh said Freeze!
And I got numb.
Can I tell em that I never really had a gun?
*unintelligible*
Now they got me in a cell,
Because my records; they sell,
Cuz a brother like me said, "Well...
hagrid is a prophet that I think you aught to listen to,
What he can say to you,
What you aught to do is follow for now,
HELL WHAT THE PPL SAY!
Make a miracle,
D!!
Pump the lyrical.
hagrid's back, all in, we gonna win,
Check it out!
YEAH Y'ALL! C'MON!
Here we go again!

 

Now that the issues is resolved. How do you like the new brakes? Did you happen to take any pics of the areas in question? Was going to get this kit as soon as my pads and rotors need service.

 

So ... I love them. They look sharp as hell. They work great. When I pulled my boat out a few weeks ago, I only had new front brakes in. My rig stopped pretty damn quick and the boat was still fully loaded with gear and fuel. I was curious and so I did a fairly hard stop from about 40mph. Amazing, and straight.

As for images, my hands were covered in antiseize so I didn't grab the phone for rotor-less pics. It's amazing how small little dabs of antiseize tend to find one's entire hand...