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Rear End locks after tightening wheels

earlymopar

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I just experienced my wheels locking up (or close to fully locking up) after snugging-up the lug nuts. They were not over-tightened. This is a fresh rebuild of an 8-3/4" with Powr Lok, properly set-up new ring and pinion by someone who does this everyday, new seals, brakes, wheel cylinders, brake lines, etc. etc. I've never experienced this before. Before adding the brake drums, I placed the (manual) transmission in neutral and rotated the axles (no issues). I made sure the adjusters were backed-off to easily slip on the brake drums and then checked axle rotation again. All fine. I put on the wheel/tire and lug nuts and tightened them in sequence to roughly 50 lb-ft. There was no further adjusting of the brakes but the wheels will not rotate by hand at this point. I have the same backing plates and drums as before the rebuild. I've checked my new brake shoes and they are actually slightly narrower than the originals. Anyone had an issue like this before? I've been told that Sure Grip rear ends will do as I experienced but only if the transmission is in gear when tightening the wheels.

- EM
 
Tighten the drums on without wheels, using a few washers and at least 3 nuts. New gaskets everywhere and bet your drums are against the backing plates.
 
Is the axle end play adjusted too tight, which may bring drums in closer to backing plates?? Is the little "button" in the center section that holds the axles apart missing? They do tend to fall out.....Just a thought.
 
Is the axle end play adjusted too tight, which may bring drums in closer to backing plates?? Is the little "button" in the center section that holds the axles apart missing? They do tend to fall out.....Just a thought.
Better yet, was the little button put back in with the rebuild.
 
No issues with the Buttons. With my setup, DrDiff says they can be left in or taken out. I removed the brake shoes and all brake hardware except the wheel cylinders and then slid on the brake drums and wheels. After tightening the wheels they spin nice and free. I’m suspecting either the wheel cylinders are incorrect or the wheel cylinder push rods are too long. The push rods came in a kit of springs, self-adjuster plate and cable, etc.

- EM
 
Drum lip is hitting the backing plate. Some aftermarket drums have a deeper lip. If its very little make a 1/8" spacer out of aluminum and place it between the drum and axle. If not you may have a mismatch of backing plate to drum. There are different offset backing plates, drum widths, and axle offsets. Recently saw this issue on a friends A body. It had A body backing plates with B Body drums and axle offset. Drums were wedged solid when tightened.
Doug
 
Got any pictures?
 
What about too wide brake shoes?
 
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No issues with the Buttons. With my setup, DrDiff says they can be left in or taken out.

Useing "Green Bearings" you can leave them out. Taypered roller bearings you might want to leave them in for proper bearing preload.

If you're using Green Bearings and have the thrust buttons in, they could interfere with the axel bearings seating all the way. I don't believe that would cause the binding that you are having though.

As you are tightening the wheel nuts, keep turning the wheel and stop when it first starts to drag. Might help you determine what's making contact.
 
If it's locking up with the nuts tightened down there is a friction point between when the wheel turns and stops turning. Where does the grinding noise come from before it locks up. :BangHead:
 
Drum is not hitting the backing plate and is not mis-matched. This is the same drum and backing plate that is original to my truck. Again shoe width was checked earlier as stated and is not an issue. Also as stated earlier this morning, the thrust buttons are not an issue given after removing the brake shoes that eliminated the wheel locking up issue. Until I get back to it, the problem appears to be the wheel cylinder or wheel cylinder push rods not allowing the shoes (at that top location) to move far enough inward. Due to this, the drum is going on over the brake shoes slightly eccentric to the backing plate and axle. This eccentricity caused by the wheel cylinder is the cause of the locking issue.

- EM
 
Drum is not hitting the backing plate and is not mis-matched. This is the same drum and backing plate that is original to my truck. Again shoe width was checked earlier as stated and is not an issue. Also as stated earlier this morning, the thrust buttons are not an issue given after removing the brake shoes that eliminated the wheel locking up issue. Until I get back to it, the problem appears to be the wheel cylinder or wheel cylinder push rods not allowing the shoes (at that top location) to move far enough inward. Due to this, the drum is going on over the brake shoes slightly eccentric to the backing plate and axle. This eccentricity caused by the wheel cylinder is the cause of the locking issue.

- EM
Hey their buddy ,did you ever figure out your problem, having similar one ,
 
..............did you ever figure out your problem, having similar one ,

If the wheel cylinder locked up, replace it.
Before you do that, make sure the parking brake cable is fully retracted and the shoe springs are allowed to pull them into the pin.
 
Well found my issue, hope this helps , normal righting pattern for me is to start at top and tighten in star pattern, but found that starting in bottom and going to the top no problem binding ! Why cause the replacement wheel studs didn’t have sufficient shoulder to hold drums in position, more like frt studs !Strange but that’s what I found!
 
So those studs allowed the drum to get off-center and then the brake shoes drug on the drums?
 
Yes apparently so , ckd everything else as you previously spoke of and found no other problem, but this became my fix , hope this helps!
 
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