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shock mounts

guilty1

Junior Member
Location
Pittsburgh, PA
I was wondering if anyone knows where I can purchase a new set of rear shock mounts for my 1978 K10. I am considering using bolts from Home Depot.....should I purchase a high grade bolt? Stainless, perhaps? Any help is greatly appreciated!

Thanx!
 

Chuck Smith

2000 Club Member
Location
NJ
I put Monroe Magnums on my 80 GMC K/20 last summer, and they came with new bolts (upper mounts). Try an Auto Zone or local auto parts store first. Forget the stainless, and be sure to use Neverseize instead. Shock mounts and 99% of automotive fasteners are grade 5. Home Cheapo sells mostly Grade 2 bolts. Grade 2 is definitely not for shock mounts (or anything else on a vehicle IMO).

As far as the rear shock mount, it is not a "bolt", but rather a "stud".

In the diagram I just made, you can see the short end goes through the truck frame, and is held on by the nut and lock washer. The shock slips on to the shoulder of the stud, and the shock is held on by the washer, lock washer and nut. The large part at the end of the shoulder that goes against the truck frame generally has 2 flats on it, so you can hold it with a wrench to tighten the nut against the frame. I believe the nuts are 7/16" thread, and use a 3/4" wrench. The flat uses a 7/8" open end to hold it in place while you tighten the nut against the frame.

At the auto parts tore, see if they have a listing for a rear shock "hardware kit". If not, try Superlift, Rough Country, Rancho, Explorer Pro Comp, or Heckethorn Big Yellow. I am sure you will have no trouble finding a stud (rear shock hardware kit).

~Chuck

shockmount.jpg
 
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guilty1

Junior Member
Location
Pittsburgh, PA
Thanx Chuck!!! I bought some Gabrial Gas Rider LT shocks and the mounts were included!:eek:. The prevoius owner used some sort of bolt set up, that was loose (now I have a oblong bolt hole), but was rust welded! Had to cut off with 4 1/2 inch grinder.:gunsfiring:

Very nice diagram....that is indeed what they look like......after I removed them from the plastic bag! :eek:

:help:I have replaced the rear, and have not won a service manual from E-bay, yet....was wondering if anyone can give me the torque specifications for the axle u-bolts, the differential cover bolts, shock bolts (instructions with shocks said atleast 100 # on mounting stud).

Chuck mentioned antisieze compound for the shock mounting bolts....should I use some of this on the axle u-bolts? I could only find the 3 1/4x 5/8 ubolts at NAPA....the nuts are not self-locking, I put new washers and lock washers on....I was told the OEM ones were self locking....these too were rust-welded.....grinder with cut off wheel got a lot of use this weekend! Should I leave the lock washers on? .....package said to re-torque axle nuts after 1200 miles, just didn't say to what.
 

75

PlowSite.com Addict
From a 1977 Chevrolet light duty truck (factory GM) service manual:

Spring to axle U-bolt nuts: 140 ft/lbs

Differential cover: 1/2-tons 20 ft/lbs, 3/4 and 1-tons 30 - 35 ft/lbs

Shock absorber: Upper 140 ft/lbs, lower 115 ft/lbs

Antiseize is always a good idea IMO, regarding the nuts I'm not sure about 1/2-ton, I know on my 1-ton the U-bolts are fine thread, with hardened flat washers and tall nuts (all bought from a good spring shop) and no lockwasher in there. Properly torqued, they've always stayed put.
 
75 makes an excellent recommendation regarding a visit to a spring shop. They can custom-bend any sort of spring U-bolt for you while you wait, and they shouldn't cost any more than $5 - $10 each! Likewise for the nuts and washers: the nuts are "tall" and they don't need to be self-locking. The washers are parallel-ground, hardened and thick. Usually about $0.10 - $0.50 each, and you KNOW they're the right pieces!

DJS
 
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guilty1

Junior Member
Location
Pittsburgh, PA
Thanx for all of your help. My uncle had an old book for impalas and it said only 45# for the u-bolts.....very glad I left that question on the board! Thanx 75!!

I am about to re-torque the u-bolts on the up-coming weekend....I didn't use hardened washers...should I swap them out? And if I do, will I have to re-torque the u-bolts again in a few weeks?

This is for a 12-bolt, half-ton rearend. Just for the record the u-bolts were 5/8 by 3 1/4 and definetly a fine thread. $10.00 a piece at NAPA.....no washers included! :gunsfiring: Seemed like I could have gotten a better deal with a kit from Summit! Just for grins, I am going to call a spring shop tommorrow.......
 

75

PlowSite.com Addict
You're welcome, guilty1 ! :)

I'm not sure what size the U-bolts are supposed to be for a 1/2-ton (manual gives the torque specs but not the bolt sizes) however the ones on my 1-ton rear axle are a 9/16 diameter U-bolt, and I measured the axle tube on an old axle that come out of a 1980 Chevy 1/2 ton 4x4 and the tube was just under 3" diameter. So if they fit up properly and are a proper spring-to-axle U-bolt, I would feel the ones you have now are OK for the job.

I'd definitely switch to the hardened washers, and then check and re-torque them again after the 1200 miles/few weeks mentioned previously.

Other than gravity, those U-bolts are the only things holding the truck on the axle and U-bolts that aren't checked and re-torqued properly can cause the rear axle to wander around when/where it shouldn't, with potentially disastrous results............. :eek:
 

Chuck Smith

2000 Club Member
Location
NJ
I agree with Rob. Get the hardened washers, install, and retorque. Unhardened washers will keep compressing each time you torque the nuts.

~Chuck
 
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