Wobbling rear wheel/s

[slowboy]

I had my '72 GMC C1500 on jackstands while doing TH350 transmission filter and gasket change. After I got done and put transmission fluid in I started truck and was going through the gears. While doing so I noticed back driver's side wheel was spinning, but was wobbling.
I know the wheel and tire is ok because I had the wheels powder coated and when the tires were remounted they balanced out good.
When I set the truck down on the ground and drove it I didn't notice any kind of rearend shake or shimmy.
Can anyone tell me what/why the wheel was wobbling while on stands and what needs to be done to fix it please?

Thanks in advance y'all!!

Keith [slowboy]

[kwmech]

Wobbling how? side to side.........up and down?

[HO455]

Several things to look at.
Is the wheel seated completely on the drum? (Assuming drum brakes)
Is the drum completely seated on the axle flange?

If all that is good then it's time to check to see if the axle is bent. Remove the tire and brake drum. You will be checking the axle for run out. Ideally using a dial indicator but a stiff piece of heavy wire will work.

https://youtu.be/1w21GwZXmZ4?si=4fBLJOPujJMh1TgJ

Attach the wire to the axle, (clamping it will work as long as it is secure) then bend the wire so the end is pointing at the axle flange as close to the outer edge as you can without touching it. Have someone rotate the axle slowly while you watch the relationship of the flange and the end of the wire. If the axle is straight and true the distance between the flange and the wire will not change. If the axle is bent you will see the wobble again but on a much smaller scale.

If this shows the axle to be true its time to take the wheel to the shop for another look at it.

[howzzzit]

Originally Posted by HO455

Several things to look at.
Is the wheel seated completely on the drum? (Assuming drum brakes)
Is the drum completely seated on the axle flange?

If all that is good then it's time to check to see if the axle is bent. Remove the tire and brake drum. You will be checking the axle for run out. Ideally using a dial indicator but a stiff piece of heavy wire will work.

https://youtu.be/1w21GwZXmZ4?si=4fBLJOPujJMh1TgJ

Attach the wire to the axle, (clamping it will work as long as it is secure) then bend the wire so the end is pointing at the axle flange as close to the outer edge as you can without touching it. Have someone rotate the axle slowly while you watch the relationship of the flange and the end of the wire. If the axle is straight and true the distance between the flange and the wire will not change. If the axle is bent you will see the wobble again but on a much smaller scale.

If this shows the axle to be true its time to take the wheel to the shop for another look at it.

Could be not seating as stated. I had rally wheels powder coated and not one of the four would mount up to the front or rear. I used a drum sander and took off a little at a time until they fit over the drum and hub. May be your problem. You didn't mention the fronts.

[dmack91]

Just because they balanced out doesn't mean they are true. I had a set of blem 38.5" murders years ago. The shop showed me one on the balancer. The wheel was bent and the tire was out of round,both obvious on the balancer. However, it still showed balanced. The stars just happened to line up,but it can be done.

[72c20customcamper]

Since you had them powder coated the center hub hole could have a heavy buildup seen it a few times with powder coated rims . Specially if the guy goes heavy with the powder. Drum sander on a drill will correct this

[72c20customcamper]

Originally Posted by dmack91

Just because they balanced out doesn't mean they are true. I had a set of blem 38.5" murders years ago. The shop showed me one on the balancer. The wheel was bent and the tire was out of round,both obvious on the balancer. However, it still showed balanced. The stars just happened to line up,but it can be done.

I had the tires on my 85 balanced twice still had a vibration. Had them road force balanced and even though they were “balanced” they had to dismount and rotate the tires and rebalance . Vibration is gone

[slowboy]

I had the truck on jack stands for over a month and a half, probably closer to 2 and a half months while working underneath it as time/life allowed. Would/could this have possibly caused the axle housing to stress-bend [for not knowing a better word] any while being on stands that long maybe?

[HO455]

Highly unlikely. And if it did, the housing would bend but, the axles would still be true and you wouldn't have a wobble.