Read drum brake help

[Chevy-SS]

Diff fluid leak (axle seal) will cause brake binding too. Seems counter-intuitive, but will definitely lock up the brakes.

 

[PlayingWithTBI]

You don't have a bent axle?

 

[Shmee1984]

You don't have a bent axle?

I jacked the truck up and had the wife put it in gear and let the tires spin. No wobble or up and down action at all.

 

[Shmee1984]

Update. I took the drums off and had them turned. SLIGHTLY out of round, but not terrible. Still have the issues. This issue is driving me nuts. I've been working on it on and off for 2 years now. Luckily this isnt my daily driver. I'm about to say f it and go with the disc brake upgrade to get rid of these dang drums.

 

[DerekTheGreat]

I wonder if you've got the right shoes on there..

 

[Jglew82]

Just spit-balling more ideas to check... Are the backing plate bolts tight? I can't imagine why they wouldn't be, but it's an easy check. Go front to back, side to side checking your leaf spring bushings, bolts, axle mounting plate, U-bolts, etc.

 

[deadbeat]

My truck did that on my 6 lug and although the backing plate was tight, the part at the bottom of the backing plate where the shoes seated in, which had 2 rivets holding it, were loose. I drilled them out and put bolts in with locktight and it has been fine for a couple years now. You shouldn't be able to easily move your shoes around with all the springs on, except a little on the wheel cylinder side.

 

[Jglew82]

My truck did that on my 6 lug and although the backing plate was tight, the part at the bottom of the backing plate where the shoes seated in, which had 2 rivets holding it, were loose. I drilled them out and put bolts in with locktight and it has been fine for a couple years now. You shouldn't be able to easily move your shoes around with all the springs on, except a little on the wheel cylinder side.

**** I didn't even think about that one, good find. OP, I'd definitely check this next, and anywhere the shoes mount for tightness.

 

[Ron88]

He all. New to the site. Got an issue I can not diagnose. Truck is a 95 K2500 with the 8 lug, 13 inch brakes with the 8600GVW. I have a BAD hop under heavy braking coming from the rear. Cant feel it in the steering wheel or brake pedal, but you sure feel it in the seat. I've replaced wheel cylinders, shoes, drums, all adjusters and springs, shocks, bled the system, etc. No brake or ABS light on the dash is on. I've disconnected the ABS fuse. I have it narrowed down to the rear drivers side. I can pull the wheel and drum off and back in the adjuster. No hop. Once the self adjuster starts getting back to where it should be, it starts hopping again. Been trying to fix this for over two years. Its driving me crazy. Any help/tips/info would be greatly appreciated.

How about switching the rear drums around and see if the problem moves to the other side?

 

[Shmee1984]

Just spit-balling more ideas to check... Are the backing plate bolts tight? I can't imagine why they wouldn't be, but it's an easy check. Go front to back, side to side checking your leaf spring bushings, bolts, axle mounting plate, U-bolts, etc.

Been there, done that. Backing plates are tight. No grooves on them at all. Bushings all look good, etc.