71 C10 rear shock bolts breaking
 

I've had a constant problem with my truck, both rear shocks will eventually wear through the bolts and fall off. I'm not sure why at this point, but I do have 3/4 ton coil springs in her. I thought it might be a missing tracking arm but I realised I do have mine.
Additionally when I first got the truck both lower shock mounts on the rear were completely worn through. I got new mounts from lmctruck and they seem pretty solid, but again both shocks will fall off after either shearing the bolts or just wearing them down.
The truck is stock height as far as I know and I haven't done anything else to the truck suspension. When bolting the shocks on I put a washer on the bolt, the bolt through the shock and mount, then a washer and bolt on the end.
Is this something that just happens with these trucks or is something wrong? Afaik the truck hasn't been in any serious accidents, though there is a big patch of Bondo on the passenger side right above the rear wheel. Could the trailing arm be slightly bent and shearing the shocks?
This happens about every month or two, it's pretty frequent and starting to get expensive replacing 4 grade 8 bolts and nuts as well as 8 washers every month or two.

Re: 71 C10 rear shock bolts breaking
 

This is something you need looked at. This is no way a common thing. Grade 8 bolts getting sheared off is big time trouble some where. Are the trailing arms in good shape? I'd have some one looking at it real closely.

Post some pictures of it so we can have a look.:chevy:

Re: 71 C10 rear shock bolts breaking
 

Here's an album of some different angles
C10 shock problems https://imgur.com/a/EBykzCl

Re: 71 C10 rear shock bolts breaking
 

No pics on the link provided.

Re: 71 C10 rear shock bolts breaking
 

Can't see nothing out of the ordinary in the pictures but if you breaking grade 8's you need something fixed.
I've owned my 71 now for 35 years and have never broken a rear shock bolt are front.:chevy:

Re: 71 C10 rear shock bolts breaking
 

I think the shock length may be suspect. Other than that everything looks normal to me. Have you noticed any hammering when you go over bumps or hauling loads? The only time I've seen shock bolts or even the welded eye the bolt goes through break is when the shock bottoms out.

Re: 71 C10 rear shock bolts breaking
 

This would be my guess as well. Shocks are too long would be my guess as well. I just replaced a set on an ‘83 2500 crew cab and all the bolts were perfect and the shocks looked to be the original ones. My Jimmy has the original shock mount bolts and over 350,000 miles on them, so something clearly is out of whack on your truck and shock length seems most likely.

Re: 71 C10 rear shock bolts breaking
 

I would have thought the same thing as ya'll but he made no mention of anything in his first comment's.

So what about it 71C10Guy, any bottoming out, may have some worn out springs also. :chevy:

Re: 71 C10 rear shock bolts breaking
 

Your shocks are too long and are bottoming out, bending the bolts and eventually breaking them....

Grab a new set of the correct length shocks next time you chew thru the bolts...

LMC part number 38-1695....KYB Gas...need two...$59.95 per shock...

30-0363 are the bolts need 2
30-0820 are the nuts need 2
30-0680 are the lock washer need 2

Hope this helps...
:chevy::chevy::chevy:

Re: 71 C10 rear shock bolts breaking
 

C10guy

Are you using the proper shock shoulder stile bolts, just a thought.

Re: 71 C10 rear shock bolts breaking
 

Is there a rubber snubbed to keep from bottoming out? I didn't see any.

Re: 71 C10 rear shock bolts breaking
 

As Dale mentioned, there should be a rubber snubber mounted to the chassis above the differential housing to prevent the housing bottoming out on the shocks....

LMC has them under 30-1875....around $10 each...

Question...Is it the upper mount bolt that breaks or the lower one? The lower one is in single shear and prone to move around if it is not tightened to specs....
:chevy::chevy::chevy:

Re: 71 C10 rear shock bolts breaking
 

Grade 8 bolts were mentioned at one point but grade 8 bolts should never be used in situations where shear forces are anticipated. For the same reason that you would never use a file as a pry bar.
From the photos it may be possible that all of the oil has leaked out of those shocks and they may be seizing up when hot.