U-Bolt Protocol… Tips and Pointers when U-bolts are Involved

Lets face it. Most of us are on a budget. So If you are working with a set of leaf springs for your lift here are some quick tips and pointers to follow in regards to your U-Bolts. Whether you are installing a lift or doing a repair hopefully this helps you make the right decision and gives you some useful information…

First and foremost NEVER re-use U-bolts. Even if they are relatively new with a low amount of corrosion. The risk is actually much higher than you think for your old U-bolts to fail on you because they have already be torqued down to their previous specifications. Its the type of thing that if you have to remove them for a repair or upgrade you should get new ones.

Plated U-bolts don’t need to be torqued as much as non-plated U-bolts. So don’t over do it when torqueing them down. This same rule goes for the grade of the U-bolts you are using for your application. Grade 5 doesn’t need to be torqued as much as a grade 8 U-bolt. Torque specs should come with the parts for a lift or Repair kit, or you can find the OEM service manual for the original torque specs if all else fails. U-bolts that have been well lubricated with an anti seize compound will have a torque range somewhere between a plated and non-plated U-bolt. (SEE TABLE AT THE BOTTOM OF THE PAGE)

When tightening your U-bolts always use a cross pattern sequence.
1 4
3 2
So you tighten #1 then #2 to a partial torque. Then partially torque #3 and #4. Using the same sequence fully torque the U-bolt nuts to the recommended Ft. lbs. called out in your kit or service manual.

U-bolts that have been torqued to a set preload are recommended to be re-torqued after a short time to take up the stretch in the material. So after installing your new lift kit or replacing your U-bolts check them after a few hundred miles and re-torque them.

GENERAL U-BOLT TORQUE GUIDELINES

Size Material Grade Ft. lbs Plated Ft. lbs Non-Plated
3/8″ 24 5 21 28
7/16″ 20 5 33 44
1/2″ 20 5 52 70
9/16″ 20 5 75 100
5/8″ 18 5 107 143
5/8″ 18 8 132 177
3/4″ 16 5 190 253
3/4″ 16 8 234 313
7/8″ 14 5 304 405
7/8″ 14 8 375 500
1″ 14 8 758 1010
1-1/8″ 12 8 848 1131
1-1/4″ 12 8 1163 1551

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