F 600 rear axle update

[crsutton81]

I posted awhile back that we started having trouble with the rear axle repeatedly snapping off the 8 studs and cones that hold the axle to the wheel hub. We removed all of the broken studs and re-threaded the holes that they fit into. The bearings checked out good on the offending wheel. This may or may not have been the best thing to do, but instead of going back with the 2 PC studs that would come loose in 2 different places each, I used a regular grade 8 capscrew bolt with the correct cones and lock washers on them. So far so good ! We have hauled plenty of soybeans with it so far that the previous normal problems would have already shown up. Hopefully the repair will continue to last.

 

[deeretails]

I hadn't seen your previous posts, I worked for a fleet years ago that had a bunch of Ford and IH rucks with Detroit Locking differentials. We couldn't keep axle studs from breaking. Eventually we installed open differentials in the trucks and no more axle problems.

 

[caterpillar guy]

As long as it works keep going and finish up. I would suspect a couple problems with that axle. 1 the wheel bearings could be a bit loose allowing the wheel to flex the hub to the axle and bolts. 2 the bearings might be a bit loose on the differential carrier inside. This will require a differential removal and or adjustment to the bearings there. Might be able to tighten them though the removal would make it easier to work on. Then another thing would be if the spider pieces have worn in the bore where they turn in the housing while turning corners letting the axle flex the bolts again. Or maybe the axles are not the right ones for the differential letting the splines not ride correctly in the side gear splines binding at the splines.

 

[Steve@Advance]

Did you check the bearing preload?

If here is play in the bearings, something will give, either the bolts or the end of the axle.

 

[wore out]

(quoted from post at 05:33:45 11/22/22) Did you check the bearing preload?

If here is play in the bearings, something will give, either the bolts or the end of the axle.

NO preload on those bearings, 0.001'' to 0.003'' of ENDPLAY is the typical specification.

 

[MARK ROBKE]

Wheel bearings should never have preload. In my 40 years as a truck tech, this was taught and emphasized many times. Specs are usually .001-.003, just as wore out said. I never saw axle studs break, and we did many hundreds of wheel seals and brake jobs. Mark.

 

[john in la]

Hummmm.

 

[crsutton81]

We we did jack up the rear of the truck and turn, jiggle, then feel of the bearing holder nut. There was zero flop whatsoever, nor slackness for the bearings on either end of the drive axle. They turned smooth with slight resistance like I'm accustomed to for a properly tightened wheel bearing. Everything else about it looked good also. The only thing I can figure is the 2 PC studs would start working loose just enough on the stud portion, then the nut and cone, to start the domino effect of just plain falling out or getting sheared off. I'm hoping the regular grade 8 bolts will eliminate this problem as there is only 1 place for it to try to unscrew from, and they have a dab of thread locker on em.