Shimmy/wobble in rear

[Houston Ben]

Hey all, I have an 86 c10 with a 85 rear end and have a shimmy/wobble in the rear. I jacked up the rear and ran it (didn't video that part ) and the wheels wobbled pretty bad. they weren't moving in and out, but like they were out of balance. I had them balanced this past Saturday but no luck. at least one of the tires took 15oz to balance which probably aint that good. In the vid's posted you can see I can move the axle in and out approx 1/8 - 1/4 inch and if I go side to side or up and down they move a little. Also, the drive shaft is smooth as butter. I have not replaced the axle bearings, they are the same as when I bought it. The wobble/shimmy shows up between 40-50 mph and gets worse the faster I go. I can drive it but it is really annoying!!

Can anyone help this poor soul?

https://www.youtube.com/watch?v=VW_Z...ature=youtu.be

https://www.youtube.com/watch?v=a0n5...ature=youtu.be

[nonstop]

I can't watch the video because it's private. I would go one step at a time. Two issues of potential concern are:

Up and down movement of the shaft. Check the bearings and axle shafts for obvious wear. That would likely show up more as a noise than a wobble, but since you brought it up, it is worth checking. In and out doesn't sound excessive.

Try rotating the wheels, or throw on a different set altogether. If a wheel takes almost a pound to balance, there is an issue. Did the person balancing the wheels dis mount them and try rotating them on the wheel to get a better balance? How old are the tires?

[Dead Parrot]

If the truck steers fine and the front end runs smooth, swap the front and rear tires. If the problem migrates to the front, its the rear tires/wheels. If it stays, it is likely something wrong with the drive train.

For something quicker, if you have a good full sized spare, swap out with the tire that took 15 oz to balance. It is possible that tire is going out of round at higher speeds due to some defect.

One somewhat easy thing to check and do is inspect your drive shaft for dents, bends or just being caked in thick layers of grease and dirt. I keep having to remind myself that the drive shaft is spinning at engine RPM when the transmission is in a 1:1 gear. We worry about perfectly balancing the engine and totally ignore the greasy mud coated drive shaft.

[slotard]

I can't see your videos either.

If you can push the wheel in/out 1/8-1/4" there's something wrong. Is the axle housing moving that much as well? I'd take a look at wheel bearings.

[Joeys82c10]

Maybe a belt in the tire is gone. I've seen one looked fine sitting still 55 it would expand and put a big bubble it the tread.

[Houston Ben]

Looks like I forgot to hit publish, try the links now. I have a buddy who has a 69 vett I am gong to see if he will let me switch his rims and tires to see if that is the problem but he won't be back till the end of the month.

[slotard]

It's hard to tell in the video, but if the wheel is moving in and out there the problem isn't the wheel. It's something to do with the rear end.

[Houston Ben]

Thanks for the replies. it is just the axle that is moving in and out. How much play is normal for the 10 bolt axles?

nonstop, I rotated the tires and same thing. I will get with my buddy when he gets back to try his set.

I will take a look at the wheel bearings and replace hopefully this weekend.

[Jaysonb]

I don't think that bad wheel bearings are going to give you the end play that you have. You should pull the diff cover, and have a buddy push the axle in and out, while you look at where the end of the axle meets the cross pin. Something in that area is most likely causing your excessive end play. Look for damage or excessive ware on the axle ends, or the cross pin, or the c clips.