5 ton camber adjustment

[Russ Knight]

After searching the forums I now ask, is there a way to adjust camber on a M939 series vehicle? My front right tire is out significantly.

Thanks!

 

[sandcobra164]

I don't know if offset kingpin bushings are available for these axles or not. When viewed from the front, the top of the tire is leaned further out than the bottom on my truck. It drives just fine down the road but I have noticed a slight amount of cupping on the tire. I'm just going to move the tire to the rear and keep riding for now. I'll try to post a picture this afternoon. It wasn't as evident when it had the 11's on it but the 14's seem to magnify the appearance of the issue.

 

[WillWagner]

Have you raised it off the ground to see if there is an issue with the bearings or knuckle?

 

[someoldmoose]

Have you raised it off the ground to see if there is an issue with the bearings or knuckle?

Yup, what he said. If the bushing(s) are worn the angles will be off. Last I knew ( 25 years ago ) there were no "offset" bushings for Rockwell's but who knows what is available now. Unlikely, but ya might have a bent housing. Monster trucks bend 'em often. They can be straightened but it's not a fun operation. Unless it's affecting handling, or causing gross tire wear I wouldn't fret about it, IF the bushings aren't bad.​

 

[sandcobra164]

I have on my truck, no unusual slop or freeplay during annual services. I've never launched it through the air, not sure about the OP's truck.

 

[Russ Knight]

Yup, what he said. If the bushing(s) are worn the angles will be off. Last I knew ( 25 years ago ) there were no "offset" bushings for Rockwell's but who knows what is available now. Unlikely, but ya might have a bent housing. Monster trucks bend 'em often. They can be straightened but it's not a fun operation. Unless it's affecting handling, or causing gross tire wear I wouldn't fret about it, IF the bushings aren't bad.​

It is gross wear.

 

[someoldmoose]

It is gross wear.

Then like Will said, jack up the front end and check the kingpins, bearings, knuckles, and hubs. One other thing, are your wheels "true" ?

No idea for a spec. without digging but excessive radial run-out can kill front tires fairly quickly too. If that were the issue though you'd probably have a shimmy in the steering wheel. And finally a silly question, are the wheel / tire assemblies balanced ?

 

[sandcobra164]

First 5 pictures are as my truck currently sits this afternoon. If you look closely at the pictures of the individual tires, you can see a slight amount of positive camber that looks pretty even on each side. Pictures 6 and 7 are just random photos of the front end from days ago and picture 8 is my front caps before my friend Welder1 took the splines out. I also have a set of emergency caps for when I need 6X6. Yes I know that the transfer case is air shift but with the splined caps on the front tires are still turning the drivetrain which results in friction losses and tire wear as well. My truck also turns a bit sharper in parking lots and feels a bit freer moving down the road (subjective observation, no data to back it up). It may help your tire wear issue some and I'm sure Welder1 would be more than happy for you to contact him. He has the equipment to handle almost any task and I happy he's a good friend of mine.

Russ Knight, I sent you a message. I can text you higher quality images (or anyone who wants them) of these pictures.