Axle/hub moving

[Bryan O]

I have a ‘18 Z521c and the rear hub on the driver’s side has recently started moving out of position on the axle. I first noticed it and pulled the wheel off and saw it was loose on the axle. I repositioned it and tighteded the through bolt. A short (2 mile) trip and it moved again. I then re-set it and tighten it till I broke the bolt! Went and bought a new grade 8 bolt and nut. Reindexed it and tightened back in place. I put 160 ft.lbs of torque on the bolt. It seemed like it was going to be fine, but after roughly 2 hours on the highway it moved again! When it moves, the hub goes up, and the tire rubs the sturup step on the fender. The grooves in both the hub arm and on the axle seem good. I cleaned them with brake cleaned and they are good. I put a lot of miles on between Houston and Rayburn. Wondering if the hub/arm has stretched?

[mactlman]

replace the pinch bolts with better bolts and torque to 150 lb ft. and retry it. hopefully the splines are not too far gone already-- bolts likely soft at this point

https://basscatstore.com/torsion-2-bolt-kit201711.html

https://brakes4trailers.com/products...f9d0fcaa&_ss=r

[clayshooter]

Hey Mactlman, what size are the bolts ?if you know please.! Are they 1/2x3-1/2? Thanks for the help

[mactlman]

Hey Mactlman, what size are the bolts ?if you know please.! Are they 1/2x3-1/2? Thanks for the help

Description

5/8-11 x 4" Grade 8 Bolt with Grade 8 Nylock Nut and Flat Washer
A recommended upgrade from the standard grade 5 hardware supplied with torsion spindles
290-510966

[Bryan O]

That is the exact bolt I used, actually I purchased 2 (after the first one broke). I torqued the first replacement on to 170 lbs. and broke the bolt, so I set the wrench to 160 and tightened the third one to that (broke the original and one of the replacements I purchased). The splines seem fine on both the axle and spindle arm seem fine. Ive got it back to my shop, Ill pull it apart and see what I can find. Any other thoughts please post em. May just be testament of how crappy the roads are around Houston. I’ll post what I find. Thanks for all reply’s.”

[jimsch]

I don't feel 170 would break the bolt unless they were defective which is not likely.
Over torquing leaves too many issues that could show up at any time.
How do you know the torque wrench is accurate? I would get another or check yours.
It is possible the wrench is reading far enough under that it is or has taken the bolt/nut to yield.

[mactlman]

lots of chinese bolts out there get USA made ones and set TW to 150 lb ft.

[Bryan O]

I used a Grade 8 bolt and nut, and torqued it to 160. I’m thinking either the splines are worn, or the grooves. Bolt seems fine. Pulling it all apart tomorrow - I’ll report

[mactlman]

I used a Grade 8 bolt and nut, and torqued it to 160. I’m thinking either the splines are worn, or the grooves. Bolt seems fine. Pulling it all apart tomorrow - I’ll report

[wmitch2]

Sounds like the splines are worn from getting loose. Time to replace the spindle or the hub. Maybe even both just to be sure.

[Bryan O]

Well, got it back to the shop and pulled it apart. Upon inspection the splines in the arm seemed pretty worn. The axle looked pretty good, and the splines were still sharp. Got a new arm and put it on. Seems tighter, and I think it’s fixed. On a somewhat related subject, the parking brake is a paining the rear, and mostly worthless. I’ll probably demo the whole thing next time I have the wheels off. For goodness sake get a brick, stone, board, anything for chock for the wheel!

[Jbass123]

I’ve carried a 16” chunk of 4x4 post in the boat for years. They make nice polyethylene wheel chocks, but I already had a chunk of 4x4. Cut a little bevel on one side just to make it fit tighter to the tire. That’s the extent of my woodworking skill.

[Capw]

Well, got it back to the shop and pulled it apart. Upon inspection the splines in the arm seemed pretty worn. The axle looked pretty good, and the splines were still sharp. Got a new arm and put it on. Seems tighter, and I think it’s fixed. On a somewhat related subject, the parking brake is a paining the rear, and mostly worthless. I’ll probably demo the whole thing next time I have the wheels off. For goodness sake get a brick, stone, board, anything for chock for the wheel!

I disconnected the parking brake at the caliper. It would always hang up.