Rear brake clunk/knock/bang when cold at light pedal pressure

[BigJ]

I have 48+k miles on my 2010 SCab, and I was still running the original brake pads both front and rear. I don't beat the snot out of it, but I don't baby my truck either. Its a daily driver that's seen more than her fair share of off road miles. I knew the front pads were ready for replacement, but the rears had probably 15k miles of life left to 'em.

A few days ago I started to notice a loud clunk when she was cold, under light braking at slow speeds. Basically, as I'd pull out of my driveway and start to turn onto the street, just as I'd start to engage the brakes via the pedal a loud knock could be heard and felt, coming from the rear.

After some investigating, I figured out where it was coming from. Here's a vid that shows exactly what was up:



This is happening on both sides. Pulling the caliper in the direction of rotation (as seen in the vid) is simulating what's happening when brake pressure is applied via the pedal, and the pad grabs the rotor . The friction is throwing the whole caliper into the hanger, creating the clunk.

So how did this happen, all of the sudden after 48k miles? Did the pad backing suffer one too many heat cycles and shrink? Has it always been this loose but is now just starting to clunk around for some reason? I have no idea. All I do know is that a new set of (non OEM ceramic) pads fit in there nice and tight and the clunk is gone.

Hopefully this helps someone else save the time, 'cause this was one pain in the arse to track down!

 

[Smokinjo]

What were the first set of replacements you had a problem with and had to take off? Were they OEM and then you had to go ceramic? Not the worn out ones, but the first replacements you had to remove as described in your other post. I'm just curious.

 

[BigJ]

I have to apologize for that; I was in a hurry and I didn't explain myself very well in that first post in that other thread.

The pads that had the problem were the original OEM pads, with 48k miles on them. There was no second set of rear pads before installing the ceramics.

So again just to be clear, its the OEMs that developed the clunk for some reason suddenly at 48k miles, and that are shown in the video. Replacing those original OEM pads with ceramic new ones solved the problem.

 

[pirate air]

Factory pads will do that after time. If you run your finger across where the pad seats against the bracket you can probably feel the deformed metal. Happens to any manufactures that use similar designs.