drive shaft woes

[alderan33]

I need help with this one guys. It's a strange one. So I am restoring my 72 C10 and I have the bed off and have been working on the frame, front end, etc.. I have the motor out and decided to replace the u joints. No problems with them. I began reinstalling the rear section of the drive shaft (2 piece) and after securing the u joint to the rear end I attempted to bolt up the carrier bearing. And it is 1 1/2" too short to line up with the mount on the truck. I did nothing with the carrier bearing. I am stumped at why and how this could happen. The truck is a long bed. The only thing I can think of is the absence of all the extra weight from the bed makes it sit differently? I could really use some advice and I would be most appreciative of any help. Thanks!

[PanhandleShantyman]

I had the same "WTH?" moment last month when I reinstalled the 2-piece drive shaft of my '69 after dropping it for the first time to replace the clutch. It was "short" at the back just as you describe, after I connected the front end of the drive shaft back to the tranny and bolted up the center support bearing bracket. But, I realized the rear section of the drive shaft can slide in and out from the back end of the center support bearing, and that had to be where I needed to make the appropriate adjustment. I guess the process of backing the drive shaft out of the differential had made it slide in at that connection point. So I just whacked the drive shaft backwards right behind the center support bearing a few times with my trusty BFH to slide it backwards until the U joint slid back enough, and hooked it back up, no further issue.

[alderan33]

Originally Posted by PanhandleShantyman

I had the same "WTH?" moment last month when I reinstalled the 2-piece drive shaft of my '69 after dropping it for the first time to replace the clutch. It was "short" at the back just as you describe, after I connected the front end of the drive shaft back to the tranny and bolted up the center support bearing bracket. But, I realized the rear section of the drive shaft can slide in and out from the back end of the center support bearing, and that had to be where I needed to make the appropriate adjustment. I guess the process of backing the drive shaft out of the differential had made it slide in at that connection point. So I just whacked the drive shaft backwards right behind the center support bearing a few times with my trusty BFH to slide it backwards until the U joint slid back enough, and hooked it back up, no further issue.

Much appreciated. I will give this a try. I actually had installed the rear of the drive shaft first. I will reverse the procedure and find a BFH to remedy the problem. Thanks again!

[Rust_never_sleeps]

Did you try flipping it the other way? ;-)

[alderan33]

Yeah I still can't figure this out. I have beat on this driveshaft but it's not budging. Any other ideas?

[Willshook]

If the mount for the carrier bearing is fore/aft, there's about 1" of adjustment slots there.

[3drburb]

Try installing the carrier bearing with the driveshaft to the cross member first, then to the rear end.

[sixty8HDC30]

am I understanding that the splined slip joint is stuck in the compressed position? if thats the case then filling it with grease at the grease point should force it to extend.

[alderan33]

Yeah I still don't get it

[PanhandleShantyman]

Can you slide the rear part of the axle any farther IN (forward) to that splined slip joint at the carrier bearing, or is it completely frozen?

If it's not moving at all, it seems like it's gotta just be stuck in the shortened position and I'd hit it with PB blaster, heat, hammer on it till it gives... maybe bolt the carrier bearing to the side of the house and swing on it? Was the axle lying out in the rain or something that could have got it rusted up?

If it moves but just not out far enough, jeez seems unlikely but maybe your first suspicion was correct and the carrier bearing is riding higher without bed weight on it and is therefore farther away? I guess you could get your heaviest buddy to jump on it and see if there's anything like that much play in the setup...

Do you have a picture of the situation just to make sure everybody has the right idea of what's going on?