Torque values for trailing arms and U-bolts needed

[chevy_mike]

Sorry for the repost from the Suspesion forum. I have not been able to get any answers to this so I thought here might be better.

Hey guys,

I am redoing the suspension on my '68 and have pulled the everything from the rear. I searched this forum and the FAQ and did not find the torque values I needed. Does anyone have this info? I need the values for,

Trailing arm bushing mounting bolt (big one that connect trailing arm to frame)
U-bolts for holding the axle to the arms

Thanks a bunch!

[Sinister]

My Chassis Service Manual for '69 says 140 ft/lbs for the pivot/bushing. 200 ft/lbs for the u-bolts.
It says torque the u-bolts first then put the weight on the suspension and then torque the bolts at the pivot/bushing.

[VetteVet]

My Haynes manual calls the trailing arm bolt the control arm front pivot bolt and says
145 ft lbs.
the U bolts are rear axle to control arm U bolts and are also 145 ft lbs.

[dave2953]

I wish I had my manual with me, but I'm at work. The u-bolt torque is an ungodly amount; I want to say 230 ft lbs. My torque wrench didn't go that high so I did mine at 150 ft. lbs IIRC. I do remember it listed separate numbers depending on whether or not you had new u-bolts or re-used the old ones. Not sure one other, but two others beat me to it anyways.

[chevy_mike]

Thanks guys. I know my impact had to work to get the bolts loose so I knew it was fairly high.

[VetteVet]

My manual also said if you have the auxiliary springs the torque is 270 ft lbs. on the axle to control arm u bolt.

[b-rad]

i allways use german specs goodntight

[WIDESIDE72]

take a 1/2" breaker bar with a 4 foot cheater pipe and tighten them til you think you might herniate yourself, then go 1/4 turn more. HAHA. sort of like adjusting the valves; "Tighten it down til it smokes, then back off half a turn."

[chevy_mike]

Originally Posted by WIDESIDE72

take a 1/2" breaker bar with a 4 foot cheater pipe and tighten them til you think you might herniate yourself, then go 1/4 turn more. HAHA. sort of like adjusting the valves; "Tighten it down til it smokes, then back off half a turn."

That's how I exploded a 1/2" breaker bar and 1/2" ratchet when I was tightening the flanged axle nuts on my '64 VW Baja Bug. They needed 230 ft. lbs. of torque and then line up the castle nut with the hole.

[Andy4639]

Here is what I have.

[LostMy65]

I've read in a couple other places that you should re-torque them after about 100 miles.
Posted via Mobile Device

[LostMy65]

U-Bolt Torque is very Important
and
Always use new U-Bolts when doing spring work

U-Bolts provide the clamping force needed to hold the springs to the axle. While some vehicles use other methods to provide the clamping force (some Camaro/Firebird's use T-bolts), U-bolts have proven to be the easiest, the most economical and most reliable way of attaching springs to an axle.
U-Bolts

Whenever springs are replaced or repaired, the u-bolts should be replaced. The threads on most u-bolts are not cut, they are rolled.

When the U-bolts are tightened, the threads are deformed by the nuts.

Obtaining the proper torque (clamping force) can never be achieved when reusing old u-bolts.

The weakest part of any spring leaf is at the hole where the center bolt goes through the leaves.

Correctly torqued U-bolts make the center section of the spring immobile.

Any, repeat, any, movement in the area of the center bolt will cause the spring to break in this area.
Cracked Leaf Spring

Breakage in the U-bolt area voids any warranty.

Never use lock washers because they can break. Also never use soft metal washers on U-bolts because they will deform under torque. Both cases will cause the nuts to loosen and will cause the spring to fail from breakage within the u-bolt area.

Always use hardened washers or flange nuts. We supply flange nuts with out 7/16 and 1/2 inch diameter u-bolts and extra thick hardened washers with other diameters.

Reusing old u-bolts is penny wise and pound foolish. (this means you are cheap)

....clip.....

Always 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.
Remember - Tight u-bolts will extend a spring's life.

From here:
http://www.eatonsprings.com/ubolttorques.htm

[LostMy65]

From www.springworks.com
3/8" - 30 ft. lbs
7/16" - 45 ft. lbs
1/2" - 65 ft. lbs
9/16" - 95 ft. lbs
5/8" - 125 ft. lbs
3/4" - 225 ft. lbs
7/8" - 325 ft. lbs
1" - 625 ft. lbs

Even more interesting info on U-Bolts & Springs here:
http://www.springworks.com/faq.html#coilq10

[project 67 sub]

i just did mine tonight but did not use a torque wrench or any torque setting. i just tightened them down as tight as i could get them with an 18" long 1/2" drive breaker bar. hope that will be good enough, will recheck them later after i get a few miles put back on her.