Rear spring - OME 891
Rear shock - OME N86C
Limiting strap - 18" eye-to-eye mounted on the shock itself.
Strap has no free play and looks like it's limiting the shock even when
the truck stands on even ground - like there is no way for the axle to drop at all.
Here is how it looks - all wheels on the ground:


What did I do wrong?

 

Did you attach it to the top and the bottom of the shock? You shold use the mounting brackets that should have came with the kit and welded it in place right below the crossmember in the rear wheel well.

 

I ordered those straps independently from the suspension parts.
They mount to the top and the bottom of the shock.
I guess I choose the wrong length though.
I read some recommendations on this forum and I thought 18" was the right length.
Hmmm... maybe the recommendations were for the frame mounted top of the strap.
What should be the length for straps mounted to the top of the shock?
20"?

 

If you are using them to mount to the top and bottom of the shock you are probably going to need a much longer strap. I would send what you have back and get the Rancho 18" limiting straps that mount to the frame. They are much stronger and they are proven to work right.

 

I would sugguest you cycle the suspension. At full droop measure the distance between the 2 mounting points of the limit strap. Just a general rule of thumb is that a limit strap streches about 1/2" for every foot in length. On mine for example was about 10.5" between the mounting points, so I got a 10" strap.

 

These are 18" limit straps;

 

This is the bottom, same tab as top, but welded to the side of the shock mount;

 

I guess I need to fabricate the top mount and weld it to the frame.
What's the distance from the frame to the hole in that top mount?

 

Most any size tab will work, you just need to measure the distance between them before final welding. The bottom tab can easily be moved up or down to adjust the length.

 

Hello...........

http://fastq.com/~sschaefer/Downey.pdf

Spells it out pretty clear.

Also:

http://fastq.com/~sschaefer/recommend.html

States:

"Upper tab dimensions: The tab is 3/16" thick steel but you could use 1/4". It is 2 1/4" long and 1 1/2" wide. The hole is 1/2" and is 1 1/2" from one end and 3/4" from the other. The end that is closer to the hole is completely rounded, the other end is completely flat. Use the Downey instructions for the exact placement. The original pieces were actually made by Rancho and were part of a limiting strap kit. As seen in the Downey instructions the Rancho tab is sort of a boot shape. This tab does not require this shape and both sides can be straight."

 

If you don't want to fabricate tabs look here Flat Tabs

 

I used specs from your website last week to fabricate those.
Thanks Steve for putting so much useful information on the website.