Rearend locked up???

[HellsK10]

I recently had my '85 K10 in my garage for a fluid change, gaskets and spark plugs. The emergency brake cable was also adjusted to reduce some slack (still has quite a bit). Anyhow, went to back it out lastnight, no problems; pulling forward however is another issue...it drives like I'm dragging a concrete barrier!
I pulled it back in, jacked up the rear and spun the drivers wheel...it spins fine backwards, but as soon as you go to turn it forward it clunks! Drums aren't locked up...ideas?!

 

[dyeager535]

Did you get two full revolutions out of the tire in reverse?

Only thing I can think of that would lock the differential up solid that would allow even some rotation with no noticeable issue in the opposite direction is the pinion shaft working out and hitting the housing or pinion, but that sure doesn't seem likely.

Even if it was the gov-lock (my first thought) locked up you'd still be able to turn both wheels in the same direction.

If you are certain the drums aren't a factor (take them off) pop the cover and take a look.

Your driveshaft is also moving freely when you rotated the wheel backwards? You are certain it's not a trans/t-case issue?

 

[HellsK10]

If the driveline is turned by hand, the passenger wheel spins with no problem. The drivers rear wheel alone is binding; dragging a little backwards, but locking up completely unmovable forward!

Did you get two full revolutions out of the tire in reverse?

Only thing I can think of that would lock the differential up solid that would allow even some rotation with no noticeable issue in the opposite direction is the pinion shaft working out and hitting the housing or pinion, but that sure doesn't seem likely.

Even if it was the gov-lock (my first thought) locked up you'd still be able to turn both wheels in the same direction.

If you are certain the drums aren't a factor (take them off) pop the cover and take a look.

Your driveshaft is also moving freely when you rotated the wheel backwards? You are certain it's not a trans/t-case issue?

 

[HellsK10]

I guess popping the wheel, drum and diff cover are in order :-(

 

[dyeager535]

I can't fathom what could possibly work one direction, on only one side, other than the pinion/side gears if something happened to them, and even then, the problem should be consistent in both directions one would think.

It could be something in the brake on that side shifting improperly, pulling a drum off and turning the axleshaft by hand is no big deal.

 

[Fordum]

Forget the diff cover until you have popped the drum off. It sounds like a classic dragging brake shoe.
Drum brakes are "self actuating". The hydraulic force does not do most of the braking.
It just forces the shoes out to the rotating drum. Then, the whole assembly rotates slightly to jam the shoes tighter, using the rotating force against its self.

When you use the hydraulics, both shoes are pressed out. When moving foreword, one shoe binds and causes the braking action.
When moving in reverse, the other shoe does the work.

This sounds like one shoe is against the drum and causing the brakes to actuate when moving foreword.
Since the other shoe is not touching, when spun in reverse, the one shoe releases but the other shoe does not have any effect.

If that is the case, you may have problems getting the drum off is there is a lip on the edge.
If so, try releasing the E-brake cable and backing off on the adjusters.

 

[HellsK10]

Spot on! Brake shoe drag coupled with next to no pad remaining :-( and a lip ;-)

Forget the diff cover until you have popped the drum off. It sounds like a classic dragging brake shoe.
Drum brakes are "self actuating". The hydraulic force does not do most of the braking.
It just forces the shoes out to the rotating drum. Then, the whole assembly rotates slightly to jam the shoes tighter, using the rotating force against its self.

When you use the hydraulics, both shoes are pressed out. When moving foreword, one shoe binds and causes the braking action.
When moving in reverse, the other shoe does the work.

This sounds like one shoe is against the drum and causing the brakes to actuate when moving foreword.
Since the other shoe is not touching, when spun in reverse, the one shoe releases but the other shoe does not have any effect.

If that is the case, you may have problems getting the drum off is there is a lip on the edge.
If so, try releasing the E-brake cable and backing off on the adjusters.