brakes grabbing or rear diff going out?!?!?!

[bucannon]

when i put my truck in reverse i notice a resistance sometimes it stops and sounds as if i hit something. I know the Ebrakes are not hooked up and the old diff was replaced....... what do yall think??

[clinebarger]

Pull drive line & inspect U-joints.
Check Pinion gear for play.
Pull drums & check brakes.
Pull the diff cover & Inspect.
More info on your truck If all this checks out? Namely the transmission.

[68gmsee]

Could be several things as mentioned by clinebarger.

As an added possibility:

I had a similar problem on my truck and did a complete rear brake job since it had original everything and still had the problem. I then checked the master cylinder to power booster pushrod adjustment and found it was off.

One thing that concerns me is you mention it sounds like you hit something. Try jacking one rear tire at a time, chock the other tires and crank the engine to see if it does it that way. If possible have an assistant listen or crank the truck to see if you can isolate it.

[D13]

My rear brakes starte grabbing on the first couple stops when the axle seal oiled them down. Once it got hot and burned off they would be better.

[bucannon]

Originally Posted by clinebarger

More info on your truck If all this checks out? Namely the transmission.

700R4 transmission, with shift kit, corvette servos, and 3200 stall converter.

the rear end is a 10 bolt from a 98 k1500 mudbogger. It had a messed up pinion bearing, messed up posi, messed up gears. so i ended up replacing the pinion bearing,diff(open), and gears(4.10). i also replaced the wheel cylinders and replaced the shoes, this was about a year ago.

[68gmsee]

Originally Posted by bucannon

.......so i ended up replacing the pinion bearing,diff(open), and gears(4.10). i also replaced the wheel cylinders and replaced the shoes, this was about a year ago.

Did you also replace the rubber brake line hose on the rear axle?

You didn't describe the problem like the one I had about 20 years ago on my other truck (1969) but it's something to be aware of. The insides had swelled up enough to force fluid under pressure to the brakes but restrict flow back with the brake spring pressure. Brake shoes were very slow to retract and eventually caused them to overheat while driving.

[bucannon]

Originally Posted by 68gmsee

Did you also replace the rubber brake line hose on the rear axle?.

no i didnt actually,i cleaned out the metal lines and connected them to the rubber line. thats a possibility. too bad im back at school now, i cant do any diagnostics until december.

the wierd part to me is the sound it makes when it decides to stop, only in reverse, so i fear it may be the pinion moving around again(maybe the pinion nut came loose?)

never buy used mudbogger parts, lesson learned haha!

[68gmsee]

Originally Posted by bucannon

..........the wierd part to me is the sound it makes when it decides to stop, only in reverse, so i fear it may be the pinion moving around again(maybe the pinion nut came loose?) never buy used mudbogger parts, lesson learned haha!

Yeah, that's why I mentioned it was a concern. When I've had problems with grabbing brakes (have had a few on different vehicles) they usually didn't make any sound.

When you get a chance try jacking the rear tire up. Do one at a time (unless you have a locking differential) and rotate backwards by hand first to see if you can feel a clunk or hear a noise.

[chip46wis]

Just went through this on my w/t I thought I backed into a brick wall---instant stop----turns out 2 springs in the brake system were broke ----I rebuilt the rears and it was fine---new springs cyls ect.

[motornut]

I've had "pings" when ujoints are going out,kind of resonates hollowish

[bucannon]

its more like a "BOOM" and stop, first time i literally got out to see what i hit... nothing. only in reverse, so i think its the pinion backing into the gears maybe? i cant diagnose it in person until december.

[storm9c1]

Brakes, possibly. Broken gear tooth in the diff, possibly. Needs more diagnosis.