Can I reuse U-bolt leaf spring stacks?
I would like to ask some questions and start a discussion related to U-bolts used to clamp leaf spring stacks on the suspensions of vehicles such as small to full size pickups, jeeps, and larger work trucks. Generally, most after-market U-bolt manufacturers recommend to never reuse U-bolts.
When should I replace the U-bolts on my suspension?
While the springs are new and the u-bolts are new, the rest of the suspension is aged and will have wear. It is common that the new parts receive additional stress than the older parts. Re-torqueing continues to move the nut up to new threads. Bottom line is we recommend that the u-bolts be replaced once they have been torqued to spec.
Can you re-use U-bolts?
Aside from the fact that the U-bolts will have been installed on an in use vehicle for 1 year, & as long as the same bolt and nut conditions exists as in scenario 1 above and there is no significant rust present, is this type of one-time re-use most likely OK ?
How often should I re-torque my u-bolts?
Eaton springs recommends to "re-torque the newly installed u-bolts after 50 miles of driving. Then recheck after another 50 miles. Then again after 500 miles. Finally, recheck the u-bolt torque every time you are under the vehicle". That seems a bit excessive to me. However, isn't re-torquing the nuts at least somewhat similar to reuse?
What is the difference between suspension U bolts and hi bolts?
How much force does a U bolt pull?
Can you reuse U bolts?
Should deep nuts be tightened?
Can impact wrenches be used on U bolts?
Will Eng tips check this out?
Can reused nuts hold torque?
See 4 more
About this website
Do you need to replace U-bolts on leaf springs?
U-bolts are a vital part of your suspension system and should never be reused. Failure to replace or properly fit your U-bolts when maintaining or servicing your suspension could cause premature failure of your leaf springs or other components with catastrophic results.
How tight should leaf spring U-bolts be?
0:312:12Torque Your Leaf Springs U-bolts Properly | One Minute MondayYouTubeStart of suggested clipEnd of suggested clipBe sure to do so in a criss-cross fashion. If your springs break between the u-bolts. It means the uMoreBe sure to do so in a criss-cross fashion. If your springs break between the u-bolts. It means the u-bolts were not tight.
Can you reuse bolts that have been heated?
If fasteners have been exposed to extreme heat or show any signs of corrosion, they should not be reused. Previous modifications made to fasteners with paint, lubrication, or other treatments also make them unsuitable for a second application.
Do leaf spring U-bolts need lock washers?
Lock washers or ordinary flat washers are not suitable for use with U-Bolts. The soft material is prone to compression, leading to a loss of torque. Only deep nuts and thick, hardened washers should be used on u-bolts.
What happens if you over tighten U-bolts?
One of the most damaging ways to do that is by over-tightening, or over torquing the fastener. This can result in stripping screws, snapping screw heads and damaging pre-tapped threading.
Can loose U-bolts cause vibration?
By definition, an under-tightened bolt is already loose and the joint does not have enough clamp force to hold the individual sections together. This can lead to sideways slippage between sections, placing unwanted shear stress on the bolt that could eventually cause it to break. Vibration.
How many times can a bolt be reused?
Repurposing Reused Screws In critical applications, fasteners should never be re-used. The criticality of the application is up to the user, but if no one can be sure what forces were applied to the fastener, new fasteners should be used in re-assembly.
Is it OK to reuse bolts?
Reuse of a structural bolt is permitted only when a bolt has not been stressed past its yield point. A quick way of telling if a F3125 Grade A325 bolt has yielded is to attempt to screw a nut onto the bolt.
What happens if you reuse stretch bolts?
However, because the tightening procedure does permanently stretch the bolt, there is some risk of breakage if the bolt is reused. And since there is no way to tell how many times a bolt has been reused, it doesn't make any sense to reused TTY bolts – the risk far outweighs the replacement cost of used bolts.
What should U-bolts be torqued to?
If the U-bolts are 9/16 inch diameter, the torque specs should be between 65 to 95 foot lbs. If the U-bolts are 3/8 inch diameter, the torque should be between 30 and 50 foot lbs.
What is the torque specs for U-bolts?
Recommended U-Bolt Torque for Cold-Formed U-BoltsSizeMaterial GradeMax. Torque Ft. Lbs. Unplated7/16 - 205441/2 - 205709/16 - 1851005/8 - 1881776 more rows
Why would U-bolts have to be tightened correctly?
centre bolts hold the spring together for assembly and help locate the spring onto the axle in the correct position. Correctly tightened ubolts are what holds the springs firmly in place on the vehicle when driving.
How tight should bolts be?
In general, you should make the bolt tight enough so that the items it is holding together stay together, but not so tight that you damage the bolt's threads. You should tighten bolts properly so that the bolt performs properly.
Reinstalling U-Bolts - EATON Detroit Spring
Dear Mike, I would like to ask some questions regarding comments at your web site stating to not reuse U-bolts. I’m really hoping you can give me some feedback based on real world experience.
Reused u-bolt failures? | Pirate 4x4
I want to know what everyone thinks on reusing u-bolts, personally i wont do it the extra 50 bucks for peace of mind is worth it to me. If you havent heard why not to reuse u-bolts its to do with the sharp threaded nut against the rolled threads on the u-bolt and when the nut is removed it cross threads the threads often you cant even see the damage.
do you reuse leaf spring ubolts? - The CJ2A Page Forums
Permanent deformation would likely only occur if you torque the bolts higher than their yield strength. Even if that occured, which is not likely, this amount of permanent deformation is not even noticiable to the naked eye.
Re using axle u bolts? - Comanche Club Forums
Factoids: The factory MJ u-bolts and nuts are as follows: U-BOLT 52002885, 4 Standard Duty *** 52003996, 4 Heavy Duty
What is the difference between suspension U bolts and hi bolts?
At the link above, part of what LH rod says is that "Suspension U-Bolts are manufactured with a smooth rolled thread, while the mating Hi-Nuts are manufactured with sharp cut threads. When a U-Bolt is tightened to its recommended torque level, the U-Bolt threads stretch as they mate with the Hi-Nuts. Although not always visible to the naked eye, this damages the threads. Removing the Hi-Nuts from the U-Bolt will cause a cross - threading that will not allow the U-bolt to be adequately retorqued."
How much force does a U bolt pull?
A force of 34,560 pounds per axle side or for each dual set of U-bolts seems huge to me unless I calculated something wrong.
Can you reuse U bolts?
Generally, most after-market U-bolt manufacturers recommend to never reuse U-bolts. I think it is good practice to use new fasteners whenever possible, but I wonder what the position of the auto manufacturers is on the issue and whether it's necessary to replace a U-bolt simply because it has been properly torqued to specs once. At the following link, you can download a small PDF product information sheet authored by Dayton-Parts who produces aftermarket U-bolts...
Should deep nuts be tightened?
Deep nuts should be tightened and re-torqued, never loosened and re-tightened.". Dayton-parts also recommends in the product info sheet to lubricate the washers and U-bolts with oil or anti-seize compound to reduce friction when torquing the U-bolts nuts.
Can impact wrenches be used on U bolts?
I tend to think at least part of the reason for the recommendations is because most shops would use impact wrenches on the U-bolt nuts which really could over-stress them. Or, they may use heat on the nuts in order to remove them and reuse the bolts.
Will Eng tips check this out?
The Eng-Tips staff will check this out and take appropriate action.
Can reused nuts hold torque?
Perhaps some confusion comes from statements like a reused nut will not "hold torque" or "cannot be adequately retorqued". Perhaps it would be better to say that more torque is required upon each subsequent reuse in order to create the same clamp down force as achieved on the first use. Statements such as not being able to "hold torque" also seem to perhaps create a misconception that the nuts are likely to loosen or back off on reuse. How likely is this ? If the threads are indeed slightly distorted, wouldn't this actually help prevent the nut from loosening once it is tightened down ?
When should U bolts be replaced?
Bottom line is we recommend that the u-bolts be replaced once they have been torqued to spec. Whether one does so or not is their choice.
Why should U bolts be replaced after torque?
The reason u-bolts should be replaced after they have been torque is because the threads are rolled, not cut. Because of this the threads are distorted when torqued. This distortion will not allow the torqued to be maintained when the nuts are loosened then retightened.
What steel is used for U bolts?
Quality aftermarket u-bolts are made to SAE standard J429 using SAE1541 steel. 1541 provide a 150,00 PSI minimum tensile strength, and 130,000 PSI minimum yield strength and a 120,00 PSI proof load. So stretching, or exceeding the yield is not something one needs to be concerned with.
Why are my springs breaking?
Because loose u-bolts are the main cause of broken springs, we suggest that they be re-torqued. While the springs are new and the u-bolts are new, the rest of the suspension is aged and will have wear. It is common that the new parts receive additional stress than the older parts.
Can you re-use U-bolts?
I basically removed the brand new drivers side U-bolts for nothing, and then found out that you are not supposed to re-use U-bolts, if that is actually considered re-use since the vehicle was never driven or moved. I even took the time to paint the U-bolts with epoxy paint and a good enamel top coat to prevent rust. The weight of the vehicle was on the springs the whole time I did the work, it that matters at all.
Can I reuse U bolts?
I reuse u bolts all the time and have for years,never had a failure.same goes for ring gear bolts, never a failure .:flipoff2:
Can loctite be reused?
I reused mine a few times, I swapped my axle in and out a few times while burning everything in. I used loctite and never had a problem.
Can you reuse ring gear bolts?
I've reused ring gear bolts plenty. I alway clean and red-loctite them. That's a whole different ballgame though, as ring gear bolts don't torque to the same levels as u-bolts and they are loaded in shear as opposed to the random loading of u-bolts (especially in an offroad rig).
What is the difference between suspension U bolts and hi bolts?
At the link above, part of what LH rod says is that "Suspension U-Bolts are manufactured with a smooth rolled thread, while the mating Hi-Nuts are manufactured with sharp cut threads. When a U-Bolt is tightened to its recommended torque level, the U-Bolt threads stretch as they mate with the Hi-Nuts. Although not always visible to the naked eye, this damages the threads. Removing the Hi-Nuts from the U-Bolt will cause a cross - threading that will not allow the U-bolt to be adequately retorqued."
How much force does a U bolt pull?
A force of 34,560 pounds per axle side or for each dual set of U-bolts seems huge to me unless I calculated something wrong.
Can you reuse U bolts?
Generally, most after-market U-bolt manufacturers recommend to never reuse U-bolts. I think it is good practice to use new fasteners whenever possible, but I wonder what the position of the auto manufacturers is on the issue and whether it's necessary to replace a U-bolt simply because it has been properly torqued to specs once. At the following link, you can download a small PDF product information sheet authored by Dayton-Parts who produces aftermarket U-bolts...
Should deep nuts be tightened?
Deep nuts should be tightened and re-torqued, never loosened and re-tightened.". Dayton-parts also recommends in the product info sheet to lubricate the washers and U-bolts with oil or anti-seize compound to reduce friction when torquing the U-bolts nuts.
Can impact wrenches be used on U bolts?
I tend to think at least part of the reason for the recommendations is because most shops would use impact wrenches on the U-bolt nuts which really could over-stress them. Or, they may use heat on the nuts in order to remove them and reuse the bolts.
Will Eng tips check this out?
The Eng-Tips staff will check this out and take appropriate action.
Can reused nuts hold torque?
Perhaps some confusion comes from statements like a reused nut will not "hold torque" or "cannot be adequately retorqued". Perhaps it would be better to say that more torque is required upon each subsequent reuse in order to create the same clamp down force as achieved on the first use. Statements such as not being able to "hold torque" also seem to perhaps create a misconception that the nuts are likely to loosen or back off on reuse. How likely is this ? If the threads are indeed slightly distorted, wouldn't this actually help prevent the nut from loosening once it is tightened down ?
