I've had 2 people tell me in the past 3 weeks that my right, rear wheels has a really bad back back and forth wobble to it. I have very minor vibrations due to it. I can feel it, but not much.

I jacked up the back and ran it in the garage. I can't see it. I took off the wheel and tire and rolled it down the driveway. It defiantly has a back and forth motion to it from wearing that way but the wheel is balanced. I looked at my axle shaft and spun it around. No bearing whines. The studs are also straight so the shaft isn't bent.

I did notice that the brake backing plate is bent inward though right on the bottom though. It was from sitting on the ground in my garage without drums on it. The rim of the drum runs over the lip of the backing plate when it all turns.

So when the wheel and drum turn is the drum wobbling over that bent backing plate and causing the whole rim to wobble? Seems like it but I can't be sure. Can I just hammer the backing plate back into shape and call it a day? Thanks!!

 

Is it just the tire or tire and wheel? Might be a bad tire, or a bent wheel.

 

I'm assuming the axle is bent considering you got it from a junked FX4. I'm assuming it was wrecked. Put the wheel on the truck while its jacked up. Then put a straight edge on the ground and spin the wheel. See how much deflection there is.

 

If you cant see it wobbling with it up in the air there isnt much you can do...check the face runout of the rim with a dial indicator, also check the runout with the wheel off, drum on and lugnuts on. then remove the drum and check radial and longitudinal runout on the axle flange face

 

Strange just the other day i happened to give my rear tire a kick while on the ground and it kinda made a weird noise like something was loose i immediately thought lug nuts but nope they were plenty tight.

I'll have to jack the truck up and see if mine is doing what your is.

 

Like i said I had it jacked up and run up to 30 in my garage with my wheels on. I didn't see anything. I did but a block of would about 1 inch away from the right tire and spun it and when it came around it hit the wood. So it's defiantly off.

I have new rims, and tires will be purchased soon. I have tomorrow off work so I am going to investigate more. Wheel could be bent but I laid the tire and wheel flat on my driveway and it didn't have a wobble to it.

I didn't get to see the FX4 I took it off of but the junkyard is reputable and they sold it to me and didn't mention anything about it. The website inventory said zero damage I believe the truck was hit in the front. They had the bed for sale with zero damage also. It was also not rolled.

The ONLY thing that I can tell is damaged in anyway is that brake backing plate. The drum has a wobble to it when i lay it flat on the ground. Has anyone has any experience with something like that? Bent drum or bent backing plate causing wheel wobble?

 

I had a bad tire that made the tire and wheel look like it wobbled. I could tell because only one side looked like it wobbled, the other didn't.

 

If you think its the wheel or tire just swap rotate it with another one and see if the issue moves. I'm going to put my money on the axle. If you had a piece of wood one inch away from the wheel/tire and they contacted while spinning you have a major problem. The axle could of been bent before the wreck too, maybe slid and hit a curb. Maybe you'll luck out and just one of your new wheels will be bent.

 

Interesting. I will swap it out with the spare and see.

When I rolled the tire down the driveway it had a defiant back and forth wobble to it. I figured it had just worn that way from the wobble due to the axle but maybe the tire is junk.

I don't think the axle is bent. I mean I had it inspected after I installed it and had a 4 wheel alignment done. My mech said the rear was perfect. If it has been off since I installed it in October I would have been having problems before late-November. And it wouldn't have been aligned.

The new wheels aren't on yet. I am still running stock.


I have tomorrow off so I will troubleshoot it. Swap wheel/tire, try to fix bent backing plate, maybe new drum if it doesn't seat right. I'll snap some pics.

I am doing a expo disk swap in January (plus the new wheels and tires) so if it's the brake stuff I'll just let it go until then. If the wheel is unbalanced I will have it remounted for the $10 or whatever.

 

An out of balance tire won't cause the rim/tire to shift an inch side to side when spinning.

 

Mike, why are you killing my hope? lol

I'm gonna start troubleshooting it. If it's a bent axle, I will get a new tube pressed in and get a new axle shaft from an Expo.

I'm gonna start small and work my way up. If I can't figure it out I will drop it off t my shop and let them deal with it. But I can say FOR SURE if it was a bent axle the rear end would not have been aligned. Period.

At this point the only known damage is the bent backing plate and drum. If that fixes it and I throw the spare on (cause the tires is probably worn unevenly now) it should be good till January.