Torque Rating Requirements for Installing Leaf Springs on a 7000 lb Tandem Axle Trailer
Updated 03/14/2013 | Published 03/11/2013
Question:
What is the torque requirements for all bolts related to the leaf spring on a 7,000 # tandem trailer. U-bolts, shackle bolts, attachment bolts to the frame? Thanks
asked by: Terry B
Expert Reply:
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.
The shackle bolts do not require a specific torque rating because 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. 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. There are some hangers that come with bolt holes on top, but they should be welded as well as bolted. If you want to use a bolt as well as welding your leaf spring hangers, then you can follow the same torque specs as the leaf spring u-bolts.
A 1/2 inch diameter bolts should be torqued between 45 ft/lbs and 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. I have attached two FAQ articles on trailer suspension for you to check out.
Product Page this Question was Asked From
4-Leaf Double-Eye Spring for 5,000-lb Trailer Axles - 25-1/4" Long
- Trailer Leaf Springs
- Double Eye Springs
- 9/16 Inch Eye
- Nylon Bushings
- 5000 lbs
- 1-3/4 Inch Wide
- 4 Leaf
- 25-1/4 Inch Long
- Standard Grade
- etrailer
more information >
Featured Help Information
Miscellaneous Media
Continue Researching
- Search Results: trailer suspension parts
- Search Results: trailer leaf springs
- Search Results: 175 80r13
- Search Results: trailer breakaway kit
- Search Results: standard equalizer trailer suspension parts
- Search Results: trailer leaf spring kit
- Search Results: mounting brackets for fenders
- Shop: 4-Leaf Double-Eye Spring for 3,500-lb Trailer Axles - 25-1/4" Long
- Shop: Lippert U-Bolt and Nut Kit for 10,000-lb Trailer Axles - 4" Wide
- Shop: Lippert Trailer Suspension Wet Shoulder Bolt - 9/16" x 2-13/16" - Qty 4
- Shop: 6-Leaf Double-Eye Spring for 7,000-lb Trailer Axles - 24-7/8" Long
- Shop: U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7" Long U-Bolts
- Q&A: What Torque Should Be Used For U-Bolt Nuts On Trailer Suspension
- Shop: MORryde X-Factor Crossmember for Standard Frame Hangers
- Shop: Dexter Heavy-Duty Suspension Kit for Tandem-Axle Trailers - 1-3/4" Wide Double-Eye Springs
- Video: Let’s Check Out the Replacement Equalizer for E-Z Flex Suspension Kits
- Video: Review of Redline Galvanized Steel UShaped BoltOn Brackets Plastic Single Axle Fender - PF1135-BKT-2
- Q&A: Recommended Replacement Leaf Springs for a Dexter 7k Axle
- Q&A: Torque Specs for Attaching Leaf Springs
- Video: Detailed Breakdown of the MORryde Rubber Equalizers for Tandem Axle Trailers
- Q&A: What Are the Torque Specs for Trailer Suspension Parts
- Article: Parts Needed to Add Electric Drum Brakes to a Trailer
- Video: Installation Guide for the Dexter Bronze Bushings on a 2022 Grand Design Imagine Travel Trailer
- Video: Review of Lippert Trailer Suspension Parts - Bushings Nylon - LC52RP
- Video: Grease Seals 10-36 (pair) Feature Review
- Q&A: Torque Spec for 1/2" U-Bolt
- Video: Dexter E-Z Flex Equalizer Kit Review
- Q&A: Replacement Bushings for Dexter E-Z Flex Equalizers
- Q&A: Does Dexter E-Z Flex Suspension Kit Have a Torque Spec
- Article: Trailer Lighting Requirements
on Trailer Leaf Springs
