Leaf springs install

I have to take my Dobinson's leaf springs off tonight to cut one of the shackle bolts shorter, and also to put the 4th leaf back in, since I'll be adding some weight to the truck. I wasn't sure when I installed them originally, so I thought I'd ask.

When I tighten the u-bolts, is there a specific procedure?

Should the truck be lifted off the ground, or should the weight be on the springs when they're tightened? The alignment shop I first brought it to pointed out that my rear axle was shifted to the passenger side about an inch, so I had always been worried I put them in wrong.

 

I know there is a thread in here somewhere about this, but if a remember correctly tighten then torque everything to spec with the weight of the truck on the suspension. As for the axle being off center, make sure it’s centered side to side and equal front to rear. But remember the rear axle is live and some times after driving or off-roading may sit to one side a bit. Good luck.

 

How would the axle shift? The pins in the leaf pack should keep it centered. The springs would have to move completely off the perch for it to shift?

 

There's a hole on the axle saddle for the leaf center pin to fit in, so no reason to be off-center.

Most people tighten the U-bolts with weight on the axle as a matter of convenience. The shackle bolts, if running in rubber bushings, should definitely be tightened with weight on the axle.

 

Well, it seems I figured out the reason for the shifted axle. Not sure how the hell it happened. I can't imagine me tightening it down like this. But it seems pretty impossible for it to shift from driving. Either way, glad I took it apart and found this! Wtf!

 

Yup. The only thing Ill add is try to tighten the nuts in a 'star' pattern in an attempt to keep everything even. Do a few turns on each 1-4, then go back to 1 and repeat type of thing..

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|||| 1 2
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|||| 3 4
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Holy fack... How tight did you torque them..? I think stock is around 40 lb ft

 

Yep, there's your problem! Now the question is will the centerpin still make into that hole with the perch dented like that?

 

The hole in the saddles are not sized to the center pin head allowing some movement.

 

Be sure to loosen the U-bolts at both wheels before you start, and only torque the U-bolts after you've done both leaf packs. Many first-timers try doing one side at a time, and have difficulty centering the axle on the center pin.

 

The numbers I saw were something like 80-100. I can't remember now. But I read that the 37 ft lbs numbers were wrong.

 

A whole inch though? Well we know what happened now that he posted a picture, it was never in the hole to begin with...

 

Yeah it's a misprint. I read somewhere it was just backwards and should be 73 ft lbs. My u-bolt flip kit said to torque them to 93 ft lbs, so that's what I did and haven't had any problems. You just have to make sure that you go back and re-torque them after you drive like 50 or 100 miles. Same with the shackle bolts.

 

I believe its 88ftlbs for the ubolts...

 

This new discovery brings about 2 new questions. An M10, grade 8 SHCS fits perfectly in the spring, and the perch. Safe?

Also, should I plan to replace that perch soon? Or will it be ok if it still nests into that hole?

 

Honestly if the bolt nest into the hole and there's no cracks in the perch. I'd say you're fine

 

I'm thinking the same thing. Grade 8 are plenty strong. And the sizes are dead on.

 

Hmm I had not heard that before. I know Icon said 70 ft*lb in their instructions for their RXT leaf pack. That was so tight it actually deformed the metal on the factory bump stops. I backed them off to / am currently at 55 ft*lb

 

Yes. The center pin just keeps the leaf pack together during shipping, and locates the leaf pack on installation. Once installed, the U-bolts take all the load. The axle perch is OK, for the same reason.

 

Music to my ears. I was really dreading getting a new perch put on.