Anybody know the torque spec for the rear U bolts? Also the center bolt. Got the parts from Mid-50's with new bushings, pins, locker nuts, center pin and U bolts . Looks like grade 5 U-bolts and I think 7/8's 14 thread. I looked on line but the numbers are all over the place. I did a search on FTE and got nonsense.

Thanks.

 

I have a 50 f3 the book I have says 170 or. so. don't have it handy right now.
they are 5/8 fine on mine

 

I checked my 54-55 manual and found in the Springs section the "Spring Clip Nut Torque Specifications" I assume that is the u-bolt.
F-100 108-125 for the rear
F-250,230 165-185 for the rear
It is 108-125 for the front

 

Yeah, I saw that too. Just not sure what a "Spring Clip Nut" is. Seems low for the U bolts. I was thinking something around 200.

 

I went out and checked mine. They measure a .555 inch. So I guess 1/2 inch.

 

RECOMMENDED U-BOLT TORQUE
Recommended U-Bolt Torque
For Cold-Formed U-Bolts



For Cold-Formed U-Bolts which have been torqued to a set preload are recommended to be re-torqued after a short time to take up the stretch in the set of the material.
U-Bolts that have been well lubricated with an anti-seize compound will have a torque range between plated and unplated values. All the above values are general guidelines.
The OEM Service Manual on specific models always takes precedence over values shown.
U-Bolts Must Be Tightened and Torqued Using A Cross Pattern Sequence
Snug U-Bolts in the seqence shown.
Tighten completely in the sequence shown.
Check U-Bolts for tightness after 100 miles

SIZE MATERIAL GRADE MAX. TORQUE FT. LBS. PLATED MAX TORQUEFT. LBS. UNPLATED
3/8-24 5 21 26
7/16-20 5 33 44
1/2-20 5 52 70
1/2-20 8 64 87
9/16-18 5 75 100
9/16-18 8 93 124
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 1,010
1-1/8-12 8 848 1,131
1-1/4-12

 

https://www.autoandtrucksprings.com/...lt_Torque.html

 

I assume you measured on the threads and that number you show would make that a 9/16" u-bolt. Just for reference my 2002 F 250 Super Duty is not even torqued to 200 lb/ft.

 

According to the chart on the attachment I posted grade 5 7/8's 14 unplated torque spec is 405 ft lbs, plated torque spec is 304 ft lbs.

 

Well, I got the tap and die set out. The U-bolts are 9/16's 18 thread. Can't find any grade marking on them. Assume they are 5. Guess I'll go with 100 pounds.

How about the center bolt through the springs? Just tight?

Hey Mid-50's: be great if you'd include torque spec's with your hardware.

 

Whatever torque you end up using it is very important that you re torque them after a few weeks of use.


B

 

I will second that. I didn't do that and one day I was working on something under the truck and checked them. They were finger tight. Oh my! I had probably only put 100 miles on the truck at that time over a year or so.

 

Yep. In practice a shop is going to reef those down with air tools. Tight. See: wheel lug nuts, oil filters, and drain plugs.

Why.. Because they don't want to see it again, ever, and a lot of people aren't going to do any retorques. Check them at least three times first 100 and say 500 miles and then during periodic mileage maintenance. Put the suspension through its paces too, just zipping around town won't do.

 

That is mention and suggested in the attachment I posted previously. If the u bolts aren't torqued properly and or not rechecked for torque this can cause movement of the spring and can cause the spring to crack at the pin locator area of the spring. It's good practice to retorque at 100, 500 and 1000 miles.

Here's the link again

https://www.autoandtrucksprings.com/...lt_Torque.html