Do leaf springs have to be torqued?
Typically 1/2 inch diameter u-bolts are used with leaf springs for 3,500 lb axles and they have a torque rating of 45 ft/lbs to 70 ft/lbs. A 9/16 inch diameter bolt should be torqued between 65 ft/lbs and 95 ft/lbs and a 5/8 inch diameter bolt should be torqued between 100 ft/lbs and 120 ft/lbs.
How tight should leaf springs be?
Tightening the shackle bolts too much will squeeze the shackle straps against the leaf springs and the whole suspension system will bind and cause problems. The best thing to do when tightening down shackle bolts is to use lock nuts and tighten them until they are snug and then backed off 1/4 turn.
Can you over tighten leaf springs?
If you over tighten either end of the leaf spring attachments… you can pinch the spring eye and eliminate all movement. You’ll know if you’ve done this because you’ll go from riding like a buckboard to riding like a steam roller.
What is the torque spec for leaf spring U-Bolts?
Torque Rating for Shackle Bolts and Trailer Suspension Components If you are using 9/16 inch shackle bolts which are the most common you will want 65 to 95 foot pounds of torque. If you are using 1/2 inch then go for 45 to 70 foot pounds. And for 5/8 inch bolts use 100 to 120 foot pounds.
What happens if you over tighten U-Bolts?
When this happens, the threads are actually cut and grooved by the nut as the nut is tightened around them. This means that if the nut is loosened back up or if it is retightened again, it is going to damage the threads on both the bolt and the nut. This creates an opportunity for the U-bolt to loosen up over time.
What grade are leaf spring Bolts?
METRIC Leaf Spring Eye Bolts, Grade 8.
Are leaf spring shackles supposed to move?
It’s recommended to tighten the shackles until snug. Once they’re tight, you’ll want to loosen them by a quarter turn. Be careful not to overtighten the leaf spring shackles. Overtightened shackles will not move along with the springs or function properly.
What does a 7/8 U-bolt torque to?
Recommended U-Bolt Torque for Cold-Formed U-Bolts
| Size | Material Grade | Max. Torque Ft. Lbs. Unplated |
|---|---|---|
| 9/16 – 18 | 5 | 100 |
| 5/8 – 18 | 8 | 177 |
| 3/4 – 16 | 8 | 313 |
| 7/8 – 14 | 8 | 500 |
Is it OK to reuse U-bolts on leaf springs?
While the U-bolt has some flexibility in its ability to stretch after being loosened, the bolt will never tighten enough to allow it to regain its full torque spec potential. The next issue with trying to reuse U-bolts has to do with the threads themselves. When being tightened, the threads stretch out under torque.
What are the torque requirements for leaf springs?
The torque requirements for leaf spring u-bolts depend on the diameter of the u-bolts that are being used. If the gross weight of your tandem axle trailer is 7,000 lbs, then you likely have two 3,500 lb axles. Typically 1/2 inch diameter u-bolts are used with leaf springs for 3,500 lb axles and they have a torque rating of 45 ft/lbs to 70 ft/lbs.
Is there a torque rating for leaf spring shackle bolts?
There is no specific torque rating for shackle bolts. You’ll want to ensure that the bolts you use are long enough so that when installed you will have at least 2 threads protruding from the nut. Make sure that the bolt you’re using has a lock nut, like part # 166081.
Do you need lock nuts for leaf springs?
Lock nuts should be used because they resist loosening with vibration or torque. Finally, I strongly recommend welding your leaf spring hangers to your trailer frame. Mounting the hangers with a bolt only will not provide a secure connection between the trailer frame and suspension, even if the bolt is torqued down properly.
Why are there two leaf springs on a Ute?
Often, on the rear ends of utes and light trucks, there’s a secondary leaf or two that come into play only when the spring is compressed by load or suspension action. The leaf spring has many attributes that appeal to 4×4 designers. The spring itself is easy to make and can be repaired in the field.