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Re using axle u bolts?


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I've always read that the primary reason u-bolts should not be reused is because of the u-bolt threads. They are rolled, not cut. When torqued, the rolled threads are distorted. This thread distortion will not allow the proper torque to be maintained after the nuts have been loosened, removed, then reinstalled and re-torqued.

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This is looking more and more like one of those situations where everyone "knows" it shouldn't be done, but everyone has a different reason.

 

What I know:

 

  • I have reused factory u-bolts on several vehicles, including my race car back in the 1970s, without having any problems
  • There must be dozens of people who have done the added main leaf AAL budget boost in XJs, and I'd bet that none of them bought new u-bolts
  • The new u-bolts I see in the parts stores look to be 3/8" or 7/16", max, and I'm sure they're made in China. MJ factory u-bolts are 14mm (.5512", which is close to 9/16" - .5625"). I would much prefer to take my chances with used 14mm u-bolts than play around with Chinese replacements that are of questionable steel, and smaller to begin with.

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No, it's a situation whereas you do what you want because no matter what anyone says, they are wrong. 

 

I had mine made, grade 8, 9/16, deep nuts. 

 

Heavy truck repair shop that made the Ubolts recommended that I torque to 80lbs. The bolts will not yield before they crush the tube of the 8.25 rear, mine are at 70lbs. 

I've reused mine three times. 

 

You buy BS Chinesium bolts............well................

 

 

Do what you want, save the arguing. 

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35 minutes ago, Eagle said:
  • The new u-bolts I see in the parts stores look to be 3/8" or 7/16", max, and I'm sure they're made in China. MJ factory u-bolts are 14mm (.5512", which is close to 9/16" - .5625"). I would much prefer to take my chances with used 14mm u-bolts than play around with Chinese replacements that are of questionable steel, and smaller to begin with.

 

 

Go to a spring shop and have them make a set of 9/16" ubolts.

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I have never replaced a u bolt except when I needed longer ones. 

 

Been reusing them for 50 years with no issue.

 

But, they were never rusty, and I liberally sprayed the threads with some kind of penetrating oil before removing the nuts.  

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13 hours ago, Eagle said:

Been there, done that. I keep a half dozen sets around, some sized for the D35 and some for the D44.

 

Factoids:

 

The factory MJ u-bolts and nuts are as follows:

 

U-BOLT
52002885, 4                 Standard Duty ***
52003996, 4                 Heavy Duty

11500756, AR              NUT

 

The Standard Duty u-bolts are shorter and used for the standard 3+1 leaf springs. Heavy Duty u-bolts are longer and are used for the heavy duty MT 4+1 springs. The u-bolt nuts are the same size for both style u-bolts. Thus there is no difference in the u-bolts except length between the D35 and D44 axles. Also the rear shock nuts and u-bolt nuts are the same.

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