Tough nuts??

[novaX522]

Trying to break loose the U bolt nuts that hold the rear end to the trailing arms. I’ve been basting them with PB Blaster several times over the last week. The threads look pretty decent, but I can’t get it to budge. I bent a 1/2” drive breaker bar. Any pointers?
I can have my friend bring his torch to heat them up, but at that point I should probably replace the u bolts.
Sounds like I answered my own question. I’ll cut them off and and get new ones. What is the torque supposed to be?

[RustyPile]

It's not a good policy to reuse U-bolts. Use a sawsall or torch to remove them...

[Steeveedee]

The torque for your fasteners will be in the specifications section of the manual for your year truck, which can be found here-
https://67-72chevytrucks.com/vboard/...ghlight=hatzie

[Chevy nutcase]

When I lowered my 66 c10 I quickly realized trying to remove the ubolts conventionally was not going to happen. I heated mine with an acetylene torch and the nuts barely moved with a 3' breaker bar so I cut the loop over the diff housing and the portion inside the trailing arm was still incredibly stuck. After pounding them out there was barely anything left. The rust swells inside the trailing arm and acts like a vise. Like mentioned earlier you'll need to replace them

[Rust_never_sleeps]

This would be a good candidate for one of those induction heaters, but they're pretty pricy yet

[Richard]

Cutoff wheel works as well for removal. Used that on my rears. 1/2"-9/16 should about 90-100 ft lbs. on the new ubolts. I am bad about specific torque and just make tight myself. Not saying it is right, but never had anything loosen in my years of abusing the vehicles.

[novaX522]

Originally Posted by Steeveedee

The torque for your fasteners will be in the specifications section of the manual for your year truck, which can be found here-
https://67-72chevytrucks.com/vboard/...ghlight=hatzie

Thanks for the link to the manuals. I had not seen that yet. Great info!

[novaX522]

I’ll get out my cutoff wheel and hope the u bolt isn’t rusted in the trailing arm too bad. I see LMC has u bolts.
How bad is it going to be to unbolt the trailing arms at the cross member?

[raggedjim]

I have a 1" (maybe 3/4") drive ratcheting torque wrench I use. My neighbor works on semi's and he gave me one that the torque readings quit working on. It's about 5 foot long.

If you cut them with a cutoff wheel, be ready for a loud pop when they let go! I used to do it that way, and honestly, it is the fastest way.

Good luck, Rg

[IIGW]

cut the ubolts, get new ones.
10 minute job

[OregonNed]

My old ones were pretty tight - the mid-torque Milwaukee made short work of them - I replaced the Ubolts too when rearend components were changed out.

[wrangler94]

Originally Posted by RustyPile

It's not a good policy to reuse U-bolts. Use a sawsall or torch to remove them...

What he said. I've swapped axles in the Jeep I used to rock crawl with 4 or 5 times. Never reuse the bolts. Cutoff wheel at top of axle tube so both halves will spin and come off the tube, then twist out of the plates.

[Accelo]

A lot of good advice. I will rehash some of it.

Use some cutting oil and a die-nut to clean up the threads. Down side is the large NF die nut is expensive. If the threads are damaged cut the U-bolt off flush at the bottom of the nut with a cut of saw or Saws-all.

I typically heat the nut to red hot using a Oxy Act tanks. Not with a cutting torch but using a rosebud. Although a Torch works well, just not as well because you are looking for a temperature differential and the faster you heat it the better off you will be.

Impacts have improved so much over the years I recommend using one. Reason is they will work fast, before the heat dissipates.

I have never had this fail me. Before driving the U-bolt(s) out double nut the end of the u-bolt threads. This way you will not damage them.

If the trailing arms are not swollen, between the two half's, with rust you have a good chance the bolt will be reusable. Inspect the bolt after removal for defects. I have never had to replace them, but I don't live where they salt the roads.
Cheers

[Richard]

Originally Posted by Accelo

A lot of good advice. I will rehash some of it.

Use some cutting oil and a die-nut to clean up the threads. Down side is the large NF die nut is expensive. If the threads are damaged cut the U-bolt off flush at the bottom of the nut with a cut of saw or Saws-all.

I typically heat the nut to red hot using a Oxy Act tanks. Not with a cutting torch but using a rosebud. Although a Torch works well, just not as well because you are looking for a temperature differential and the faster you heat it the better off you will be.

Impacts have improved so much over the years I recommend using one. Reason is they will work fast, before the heat dissipates.

I have never had this fail me. Before driving the U-bolt(s) out double nut the end of the u-bolt threads. This way you will not damage them.

If the trailing arms are not swollen, between the two half's, with rust you have a good chance the bolt will be reusable. Inspect the bolt after removal for defects. I have never had to replace them, but I don't live where they salt the roads.
Cheers

Yes, I agree heat works lot of times. Also agree not to reuse the ubolts in many situations, especially if heat was used in removal. Personally have no problem reusing a fastener in a non stress location if heated. In my experience the fastener usually needs to be replaced anyway if heat was needed.

[novaX522]

I took the cutoff wheel to the u bolts yesterday. Done in minutes. Had one hole that was rusty and had to hammer out the cutoff bolt.
The trailing arm bolts at the cross member came out super easy with hand tools.
Now I’m having a tough time getting the upper spring bolts out.

[raggedjim]

Are you reusing the springs? If not I cut the spring up closer to the frame and it makes it easier to get an impact on it.

[custom10nut]

Hit it with some “Deep Creep”, put an impact wrench on it for a few seconds to get some vibration on it, then let it set for a week or so.
Then hit it with a large impact again.
If you have a 3/4” drive, put a longer piece of pipe on it for leverage.
When all else fails hit it with a torch.
It can’t stay tight if it’s liquid.

[novaX522]

I had planned on reusing the springs, but I was starting to round off the bolt heads. So, I took the cutting wheel to them also. I’ll order a new set of springs.

[Orange Crate]

Moved my axle with a zero rate spring and needed new u-bolts. These guys had good pricing and quick shipping. i know your rear suspension is coil spring but it's a good source for new bolts.

https://uboltstore.com/

[Accelo]

Good deal. I guessed at some specifications and the total, for four bolts with nuts and washers, was under $40 + shipping.

[vics stuff]

It has been mentiones several times to heat the nut up red hot.
What has not been mentioned it to quickly quench the nut with cold water. This will shock the bond between the U bolt and the nut.
You should do this at least 2 cycles and i bet the nut will just spin off.
I use this method all the time with 100% success.
Vic