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Axle ubolt question

gba88

NAXJA Forum User
Location
PA
I had a guy replace leaf springs on a 99, chrysler axle and he re-used the ubolts. If I had researched first, I would have bought new bolts and had them replaced at the time. I have 2 questions: First: how big of a deal is it to have re-used the bolts? I've read a lot of info from both sides of the fence on this. It has about 170k on it, and I'm unsure if they've ever been replaced before.

The second question: would I be able to replace them without a lift and/or other heavy equipment? I'm assuming I'd work one side at a time, take one off, replace and then the other (4 times). What would be the method of doing this just in a garage; would I jack it up right on the axle and starting taking them off or what?

Thanks for any info, I'm getting more nervous about it the more I read about how you shouldn't re-use the old ones.
 
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I had a guy replace leaf springs on a 99, chrysler axle and he re-used the ubolts. If I had researched first, I would have bought new bolts and had them replaced at the time. I have 2 questions: First: how big of a deal is it to have re-used the bolts? I've read a lot of info from both sides of the fence on this. It has about 170k on it, and I'm unsure if they've ever been replaced before.

The second question: would I be able to replace them without a lift and/or other heavy equipment? I'm assuming I'd work one side at a time, take one off, replace and then the other (4 times). What would be the method of doing this just in a garage; would I jack it up right on the axle and starting taking them off or what?

Thanks for any info, I'm getting more nervous about it the more I read about how you shouldn't re-use the old ones.

I've reused bolts on several occasions when I needed to fix something quickly, and couldn't get to a place to get replacements. That being said, for the first few hundred miles, I pull the tire off, and ensure the torque is still there. Never had a problem. Is it smart to replace, yes, necessary... debatable. Check to see that they are still torqued, and you should be fine.

As far as replacement goes, easiest is to use a floor jack under the Diff cover (wood block for protection). Left the rear end. Use jack stands under the frame rails. pull the tires, lower the jack until all droop is out of your suspension, but it is still supporting the rear end. Undo 1 u-bolt completely at a time, and replace.

Others may differ, but this is how I've done it in a pinch. If you dont have a floor jack, you can use the same method with a bottle jack under the side that you are working on, so that the axle is still fairly supported.
 
I've reused bolts on several occasions when I needed to fix something quickly, and couldn't get to a place to get replacements. That being said, for the first few hundred miles, I pull the tire off, and ensure the torque is still there. Never had a problem. Is it smart to replace, yes, necessary... debatable. Check to see that they are still torqued, and you should be fine.

As far as replacement goes, easiest is to use a floor jack under the Diff cover (wood block for protection). Left the rear end. Use jack stands under the frame rails. pull the tires, lower the jack until all droop is out of your suspension, but it is still supporting the rear end. Undo 1 u-bolt completely at a time, and replace.

Others may differ, but this is how I've done it in a pinch. If you dont have a floor jack, you can use the same method with a bottle jack under the side that you are working on, so that the axle is still fairly supported.

Thanks for the reply and description of how to do it! I have a floor jack, and stands so that shouldn't be a problem. I just wasn't sure about how to take the tension off and whatnot. I planned on pulling the wheels and checking the torque, so I guess I'll go from there.
 
Thanks for the reply and description of how to do it! I have a floor jack, and stands so that shouldn't be a problem. I just wasn't sure about how to take the tension off and whatnot. I planned on pulling the wheels and checking the torque, so I guess I'll go from there.

I should have been a little more clear with this:

If you remove 1 ubolt, without loosening the other, it will make the plate rotate over the spring perch, and it will make it nearly impossible to remove or install the U-bolt. Loosen both bolts a little, then remove one, install new, and tighten just until its touching the or a tiny bit loose, then do the other. This will just ensure that the perch never leaves the centering pin. If it does, its not that hard to get it back in place, just requires a little muscling around. Just make sure that your plate is flat and don't tighten any bolt more than the others, you should work in a cross pattern as your tightening them, then final torque. similar to a tire.
 
I should have been a little more clear with this:

If you remove 1 ubolt, without loosening the other, it will make the plate rotate over the spring perch, and it will make it nearly impossible to remove or install the U-bolt. Loosen both bolts a little, then remove one, install new, and tighten just until its touching the or a tiny bit loose, then do the other. This will just ensure that the perch never leaves the centering pin. If it does, its not that hard to get it back in place, just requires a little muscling around. Just make sure that your plate is flat and don't tighten any bolt more than the others, you should work in a cross pattern as your tightening them, then final torque. similar to a tire.

Ok, thanks for the extra info. So, start on one side...loosen all 4 nuts on the plate on that side until all 4 are loose enough to remove by hand. Then, totally remove a single u bolt, replace then remove and replace the other. Snug them up and then do the other side.

I've read not to tighten to torque until it is on the ground, is that right?
 
Ok, thanks for the extra info. So, start on one side...loosen all 4 nuts on the plate on that side until all 4 are loose enough to remove by hand. Then, totally remove a single u bolt, replace then remove and replace the other. Snug them up and then do the other side.

I've read not to tighten to torque until it is on the ground, is that right?

I've read the same thing, but I also know it's a real pain in the a** getting a torque wrench up there (or down there, depending on how your situated) with the wheels on. That being said, I've torqued it in the air, and on the ground, and both seem to have worked just fine. Maybe someone else will chime in with an easy way of doing it loaded.
 
I've read the same thing, but I also know it's a real pain in the a** getting a torque wrench up there (or down there, depending on how your situated) with the wheels on. That being said, I've torqued it in the air, and on the ground, and both seem to have worked just fine. Maybe someone else will chime in with an easy way of doing it loaded.


If the axle is on jack stands so the weight of the vehicle is on the springs, then it is the same as if you put the tires on and put it on the ground.

Just a lot easier to torque......
 
If the axle is on jack stands so the weight of the vehicle is on the springs, then it is the same as if you put the tires on and put it on the ground.

Just a lot easier to torque......

Thanks for the post! I pulled the wheels tonight and put proper clamps on the springs (previously were hose clamps). Anyway, the ubolts "looked ok", but seemed to only be torqued about 30 pounds or so. I torqued all 8 down to 55 and put a little loctite on top of each -not sure if it made it into the threads, but figured it couldn't hurt. Going to check it again this weekend when I repair some rust holes in the bottom.
 
The biggest concern I would have with reusing U-bolts in a rusty part of the country is the bolt threads getting compromised. IF the bolts look clean, with decent threads, and also the nuts are good, then you're probably OK.

Somehow, 55 ft pounds seems low... but, then I'm running larger diameter bolt than stock.

David Bricker / SYR
 
I torqued all 8 down to 55 and put a little loctite on top of each -not sure if it made it into the threads, but figured it couldn't hurt. Going to check it again this weekend when I repair some rust holes in the bottom.

When I did my axle swap I forgot to go back and check the nut tightness after a few hundred miles. A few months later I had a mysterious clink/rattle when my rears went over a bump. Jacked it up, removed the tires and sure enough 2/4 nuts on each side were fully loose, causing the plate to rattle :shocked:

I torqued them all down and stacked a nylock nut on top of each kit ubolt nut. They've held tight since, and now I only get loud squeaking when I turn a corner and apply lateral friction :looney:
 
The biggest concern I would have with reusing U-bolts in a rusty part of the country is the bolt threads getting compromised. IF the bolts look clean, with decent threads, and also the nuts are good, then you're probably OK.

Somehow, 55 ft pounds seems low... but, then I'm running larger diameter bolt than stock.

David Bricker / SYR

I found 55lb as the spec on another site somewhere which is why I went with that. In any case, they were only about half that tight. will be checking again tomorrow.

Would it have been ok to just go with the hose clamps? I read on another forum somewhere that the clamps that bolt on aren't good since they don't let the leafs shift and cause a stiffer ride. I figured the hose clamps only were "probably" ok since all they are really doing is keeping the springs from flying out sideways....
 
update: friend called and said it made a "bang"when it hit a bump...was one of the clamp bolts hitting the top of a bent muffler heatshield. Also, said the ride was a lot different than when only the hose clamps were on it. I temporarily removed them, so it's back to just the hose/worm gear clamps for the time being. I've heard of guys using just hose clamps, but doesn't seem stable to me, I don't know. I guess as long as you keep an eye on them?

Anyway, so I guess the thing I read about the bolt on clamps stiffening up the ride was true. I don't see how the springs could slide with ANYTHING on them, though. I thought of using the clips with the 2 parts where you bend the ears over, but they would probably slide all over. The replacement springs don't have "divets" or anything to keep the clips from moving around on the leaves.
 
I try to replace my u-bolts everytime, but that is not always feasible. I have old ones on my Jeep right now, but bc of the steel shim I added to the pack and the DPG bump plates, I used fresh, clean thread higher up on the bolt. No issues at all, and hold the torque of 85ft-lbs.

update: friend called and said it made a "bang"when it hit a bump...was one of the clamp bolts hitting the top of a bent muffler heatshield. Also, said the ride was a lot different than when only the hose clamps were on it. I temporarily removed them, so it's back to just the hose/worm gear clamps for the time being. I've heard of guys using just hose clamps, but doesn't seem stable to me, I don't know. I guess as long as you keep an eye on them?

Anyway, so I guess the thing I read about the bolt on clamps stiffening up the ride was true. I don't see how the springs could slide with ANYTHING on them, though. I thought of using the clips with the 2 parts where you bend the ears over, but they would probably slide all over. The replacement springs don't have "divets" or anything to keep the clips from moving around on the leaves.

You're using hose clamps to keep your leaves together?? :huh:

My OME leaves use the "bolt on" u-shaped clamps you speak of from the factory. They allow more vertical leaf movement for flex off road and are much easier to install/replace.

The "fold over" clamps are pretty standard on any leaf spring, and come on from the factory. put on properly, they do not slide at all. It cost me $6 for 6 at my local spring shop when I did my bastard pack build. One slipped about 1/4" over 2 years.

When driving/flexing springs slide perpendicular (front to back of vehicle) to the holding force (left to right of the vehicle) of the clamps - all the clamps are there for is to keep the leaves from fanning out.
 
I try to replace my u-bolts everytime, but that is not always feasible. I have old ones on my Jeep right now, but bc of the steel shim I added to the pack and the DPG bump plates, I used fresh, clean thread higher up on the bolt. No issues at all, and hold the torque of 85ft-lbs.



You're using hose clamps to keep your leaves together?? :huh:

My OME leaves use the "bolt on" u-shaped clamps you speak of from the factory. They allow more vertical leaf movement for flex off road and are much easier to install/replace.

The "fold over" clamps are pretty standard on any leaf spring, and come on from the factory. put on properly, they do not slide at all. It cost me $6 for 6 at my local spring shop when I did my bastard pack build. One slipped about 1/4" over 2 years.

When driving/flexing springs slide perpendicular (front to back of vehicle) to the holding force (left to right of the vehicle) of the clamps - all the clamps are there for is to keep the leaves from fanning out.

The guy who replaced them said they'd be fine with the hose clamps...I asked another guy at work who has raced cars before and has his own shop. He said they'd be fine, and that "back in the old days", they didn't use anything at all...? All I know is friend's jeep has had broken springs (bottom leaf on one side, second leaf on the other) for at least a year. A guy replaced with some made packs and replaced center pins and new rear shackles. I have no personal experience with this (biggest job I've done is hubs and front axle ujoint replacements). Removed the clamps from the ends (I left one behind the wheel a few inches forward from the ubolts) and the ride is back to normal. I'm assuming the clamps weren't allowing the springs to slide.
 
As far as the torque specs, I found 52 at this thread on another forum:

http://www.jeepforum.com/forum/f11/actual-leaf-spring-u-bolt-torque-specs-1366033/


Factory specs according to my 97 FSM ....

U-Bolt Nut . . . . . . . . . . . . . . . 70 N·m (52 ft. lbs.)
Front Pivot Bolt . . . . . . . . . 156 N·m (115 ft. lbs.)
Upper Shackle Bolt . . . . . . . 156 N·m (115 ft. lbs.)
Lower Shackle Bolt . . . . . . . . 108 N·m (80 ft. lbs.)


I went with 55, should I torque them higher than that?
 
I took a look a t a couple of FSMs I have. For the XJ, it does specify 52 ft pounds. Interestingly, for a YJ of the same year ('95), it specified 80, I believe.

Personally, I'd use the correct torque for a Grade 5 bolts, of the diameter. I don't know offhand the bolt diameter of a stock XJ U-bolt. for a 7/16 Grade 5 bolt, it's 49. For a 1/2", it's 75. For 9/16, it's 102.

So, if the stock u-bolts are 7/16, then 52 ft pound as you found, and as the FSM states sounds correct. Sorry for the confusion.

David Bricker / SYR
 
I took a look a t a couple of FSMs I have. For the XJ, it does specify 52 ft pounds. Interestingly, for a YJ of the same year ('95), it specified 80, I believe.

Personally, I'd use the correct torque for a Grade 5 bolts, of the diameter. I don't know offhand the bolt diameter of a stock XJ U-bolt. for a 7/16 Grade 5 bolt, it's 49. For a 1/2", it's 75. For 9/16, it's 102.

So, if the stock u-bolts are 7/16, then 52 ft pound as you found, and as the FSM states sounds correct. Sorry for the confusion.

David Bricker / SYR

Thanks for checking into it! I pulled the wheels yesterday and checked the torque again. They did work a little loose, so I put them back to around 55. I'll just keep an eye on it and if they continually loosen, probably just replace.
 
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