Super Axle pivot slop and repair
Posted: Sat Jul 07, 2018 10:13 am
We have a member that is curious if anyone has repaired a Super front axle with excessive slop at the pivot. I have not, but here are my thoughts on it:
The parts listing doesn't show any bushing (plain bearing) in the axle, so it is just the bolt through the cast iron axle. The bolt is hardened steel, so in all likelihood the axle will wear much faster than the bolt. I suspect there is plenty enough meat in that area to install a bushing. McMaster-Carr is probably the best/quickest route to find an appropriate bushing. I think you want to look for a bushing that fits over the bolt with minimal clearance and has about a an 1/8" wall thickness.
The thru bolt is 3/4" diameter Grade 5. In actuality the 3/4" bolt should actually measure a few thousandths less than 3/4", so my guess is you want a bushing that is 3/4" id x 1" od x (length required).
The correct procedure to install would be to drill on a mill to nearly the correct size and ream to finished fit. Finished fit should be a light interference fit so the bushing doesn't spin in the axle. The only movement should be between the bushing and the bolt. Most people will not have access to a mill, so you can either take to a local machine shop or look into drilling on a drill press and finishing with a hand reamer. I'm hardheaded so I would be looking for a hand reamer to fit the bushing, but likely much less hassle to just let a machine shop fight this battle for you. Final assembly of the bushing into the axle should be with a shop press.
The bushing will also have to be drilled to allow grease to get in. It is likely best to drill through the grease fitting hole after pressing the bushing into the axle. Finally, if the bolt has any wear at all, replace with another Grade 5 and reinstall.
Any other experiences with this job would be welcomed!
The parts listing doesn't show any bushing (plain bearing) in the axle, so it is just the bolt through the cast iron axle. The bolt is hardened steel, so in all likelihood the axle will wear much faster than the bolt. I suspect there is plenty enough meat in that area to install a bushing. McMaster-Carr is probably the best/quickest route to find an appropriate bushing. I think you want to look for a bushing that fits over the bolt with minimal clearance and has about a an 1/8" wall thickness.
The thru bolt is 3/4" diameter Grade 5. In actuality the 3/4" bolt should actually measure a few thousandths less than 3/4", so my guess is you want a bushing that is 3/4" id x 1" od x (length required).
The correct procedure to install would be to drill on a mill to nearly the correct size and ream to finished fit. Finished fit should be a light interference fit so the bushing doesn't spin in the axle. The only movement should be between the bushing and the bolt. Most people will not have access to a mill, so you can either take to a local machine shop or look into drilling on a drill press and finishing with a hand reamer. I'm hardheaded so I would be looking for a hand reamer to fit the bushing, but likely much less hassle to just let a machine shop fight this battle for you. Final assembly of the bushing into the axle should be with a shop press.
The bushing will also have to be drilled to allow grease to get in. It is likely best to drill through the grease fitting hole after pressing the bushing into the axle. Finally, if the bolt has any wear at all, replace with another Grade 5 and reinstall.
Any other experiences with this job would be welcomed!