GameboyRMH
GameboyRMH UltimaDork
9/9/13 9:13 a.m.

Rear drums on my Sammy, newish shoes, old-ass drums, often submerged.

I've been suffering with a couple of problems with the rear drums for a while, I'm pretty sure they're all coming from the back-right specifically:

  1. A cyclic creaking/scraping noise when on the brakes, frequency matches wheel speed. Most Sammies and Jimnys do it. The noise stops under heavy brake pressure. Also happens if I try to slow using the handbrake. Submersion in mud actually makes it stop for a while. I thought it might be a lack of grease between the shoe and the raised spots on the backing plate.

  2. An "out-of-round" feeling, very noticeable if using the handbrake to park on a slope. It'll roll a bit until it hits the "high point" where brake grip is stronger, and then stop.

Recently a third problem has appeared: The back-right locks up much more easily than the others. If I call the normal lock-up pressure an 8, I start to get tire squeal from the back-right at about a 5 and it locks up at about 6.5~7.

I haven't looked at it yet because I'll need a slide hammer to remove the drums. Yay

Any ideas?

Swank Force One
Swank Force One MegaDork
9/9/13 9:15 a.m.

Watching this thread. My Cherokee exhibits both symptoms 1 and 2. Thinking about "fixing it" by just doing a rear disc conversion because drums are like witchcraft to me.

ebonyandivory
ebonyandivory HalfDork
9/9/13 9:22 a.m.

I'd swap right rear drum for a jy one and see if it disappears before going crazy. It's almost free. I wish I still had all my Sammy axle parts, I'd give em to ya. Hell, can you swap the left and right drums to see if the problems switch sides?

GameboyRMH
GameboyRMH UltimaDork
9/9/13 9:24 a.m.

Good idea, gotta take one side off to inspect it anyway.

Jerry From LA
Jerry From LA Dork
9/9/13 9:32 a.m.

Check the inside of the drum for concentricity. It might be round but off-center.

ultraclyde
ultraclyde Dork
9/9/13 9:37 a.m.

It's possible that the drum is out-of-round. That could give you problems 1 and 2. It's hard to warp drums, but not impossible. Usually happens by setting the parking brake like a gorilla-man when the drum are stupid hot. The creaking could be from the warped drum pushing the entire brake assembly around against the backing plate.

I've had internal bits in drums brake and make some odd noises rubbing the backing plate as well.

The early lock is usually some king of contamination. I had a Ford truck that did it when the axle seal started leaking grease into the drum. The seal surface on the housing was marred, so every 6 months or so it would start locking up the right rear with little provocation. I've seen other vehicles do it when bits of the break show material would start crumbling from overheating or abuse ( like being pummeled by warped drums.)

In any case, pulling the drums is going to be the first step. If you can swap them side to side it will tell you if the actual drum is the issue, or check them for runout/round if you have the equipment.

AngryCorvair
AngryCorvair PowerDork
9/9/13 10:00 a.m.
ultraclyde wrote: In any case, pulling the drums is going to be the first step. If you can swap them side to side it will tell you if the actual drum is the issue, or check them for runout/round if you have the equipment.

+1

GameboyRMH
GameboyRMH UltimaDork
9/9/13 5:21 p.m.

Update: It was a combination of heavy brake dust buildup and leaky actuation cylinders, which have now ruined my newish brake shoes. Just cleaning out the brake dust got rid of the noise and I think the "out of round" feeling was reduced as well.

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