What is this weird brake clunking?! Video inside (1 Viewer)

[ZIFFFZJ80]

1997 FZJ80. After the truck has been sitting overnight, there's a clunking noise for the first 3-5 minutes when coming to a stop After that, it's completely gone until next morning.

I'm pretty sure it's coming from the left rear, and it may somehow be e-brake related (the sound slightly changes when I pull the e-brake while its clunking). I don't touch the e-brake when I part the truck though. I recently replaced the rear pads and rotors hoping that would fix it (it didn't) and I looked at the e-brake components and they seemed fine... None of it makes sense! Help!

 

[BILT4ME]

Check your U-Joints.

Lube the U-Joints.

It is rotational and I don't think it's brake related. It seems to load up and release, which is common in a binding situation and could be a slip joint as well as a U-Joint on a DS.

 

[ZIFFFZJ80]

Thanks, I'll go check/lube them and report back.

 

[rc51kid]

I didnt watch your video yet. But some people have had brake caliper bolts get loose. They often hear a clunk while moving in reverse only. Then they fall off.

 

[jpoole]

does it only make the noise when you apply the brakes and stop immediately when you release them (while cold of course)?

 

[ZIFFFZJ80]

Yes, only while applying the brakes. Caliper bolts are tight.

 

[jpoole]

Initially seems in time with the white mark on the wheel but that last clack doesn't line up with the same mark. This makes sense even if the noise is axle housing but may shine light in it being the DS or not as that would turn at a different rate. Not sure this is helpful but maybe there's a clue here that someone else can pick up on?

Locking the CDL and running without the rear DS could shine some light on the cause of the noise and I'd definitely see if you can pick up on any looseness or rotational noise by lifting the rear wheels off the ground and rotating/push-pulling/etc. but that's all basic troubleshooting. I'd also see if you can check the runout in the rear disks as a warped one could potentially be pushing the pads back and forth in time with wheel rotation and possibly triggering a noise like this, etc.

 

[sogafarm]

Almost sounds like a loose rock maybe between rotor and backing plate.

 

[rc51kid]

I have had a similar noise when I bent the backing plate that holds the pads under tension. It can get bent enough that it hits the wheel as it turns. Lift it up with the wheel still torqued and in place. Spin the wheel by hand and see if you can hear it.

 

[ZIFFFZJ80]

No sound when spinning the wheel in the air. I think I'm going to pull the ds and see if it still happens.