1999 K1500 5.7 Suburban, Rear Shocks to Frame, No Nuts?

Got a weird one, I'm about to replace my rear shocks with 2X Bilstein B6 4600 (PN 24024211).

The service manual and illustrate parts catalogs both state that the shocks mount to the frame with 2X M8-1.25 X 22mm Flange Bolts (PN 11570082) and Flange Nut (PN 11609746) at 17 [N-m] (13 [lb-ft]).


However, upon inspecting my vehicle, the Flange Bolts are screwed in from the bottom, and weirdly are screwed into threads in the frame rather than through-holes into nuts.


I already have new bolts and nuts on-hand.

I see three options.
1. Attach the new shock the same way as the old shocks, directly into the frames threads.
2. Install the new bolts from the top, screwing them into the frame as best as feasible, then tighten the shocks to the frame via the nuts from the bottom, but this doesn't sit right with me.
3. Drill out the threads with a 10.5mm or 13/32" bit and install per the service manual instructions.


What should I do?

(edit 1: rescale images)
(edit 2: reupload images)

My truck has factory looking J-nuts that are clipped over a frame through-hole that the upper shock bolts threaded into. My truck has several frame items that thread directly into it, like the fuel filter and brake and fuel line clamps, but those shouldn't be removed too often... for serviceability's sake I would think you'd want a replaceable item in there if the threads ever got crossed or pulled out.

By hand they felt like they were threaded directly to the frame, but with the amount of rust it is possible that they are J-nuts from the factory and are expected to replace them with the listed flange nuts when serviced.
I will double check with an inspection mirror.

I can see the parts illustration, but not your .jpg image.

Haven't been into a Suburban. My pickups use bolts with nuts, but I don't remember if the bolts go in from the top, or from the bottom.

Nothing really wrong with clip-nuts; GM used 'em forever on front shocks for nearly every vehicle for decades. We considered them re-usable provided the clip didn't break when we unscrewed the bolts. Breaking the clips happened...but not that often.

I'd be REALLY tempted to put the new shocks on exactly the way the old shocks were installed.

Not sure if the Suburban is different, my 92 C2500 has the rear shock mount perched off the frame, similar to the illustration. The shock was attached with factory nuts and bolts.

Wildblue19 hit the nail on the head.
From the factory, the rear shocks must have been installed with J-nuts.


Apologies for the poor image. It is the best I could do at that angle.

I know that I haven't replace the shocks before, but it's possible, though unlikely, that the prior owner did sometime before 2008.
Because of that, I give each J-nut a 50:50 chance of getting destroyed beyond reuse while removing the bolt.

I just did my rear shocks the other day. 92 k1500 Suburban. Mine are factory j nuts. Use a lot of pb blaster or other penetrating oil, 1 j nut broke each side for me and it was a huge ordeal to take them off due to the fuel tank being in the way.

96 K1500

Well, at least GM is (in-)consistent.


When I needed clip-nuts for inner fenders, I found that the local NAPA had 'em in various sizes, in packs of maybe a dozen. No doubt the other parts-stores have something similar.

I had to MAKE clip nuts to hold the leaf-spring bracket on my Nova, though.

Schurkey said:

Well, at least GM is (in-)consistent.


When I needed clip-nuts for inner fenders, I found that the local NAPA had 'em in various sizes, in packs of maybe a dozen. No doubt the other parts-stores have something similar.

I had to MAKE clip nuts to hold the leaf-spring bracket on my Nova, though.

Click to expand...

My Napa had clip nuts but they were all in standard sizes, no metric. I had to go to Grainger to get new ones as the upper rear shock bolts are M8 x 1.25.