unSquare K5 Floor Repair DIAMOND PLATE fabricated supports

First tech post hopefully pics go through

Attempting to fix my unSquare K5 project. Body Tub is ROTTED but upper 3/4 of Body is acceptable to save.

I understand these bodies are like wet noodles once the supports rot away.

I am attempting this repair in my gravel driveway which is seriously inadequate for leveling and jacking but its the only place I have to let this truck live long term while I fix it.

I have welding experience and some Fab experience.
I am a Auto Mechanic and Machinist by trade so I understand how things work. This is certainly not a beginners body man project (which I am) but I am determined to get er done.

I envision using some UniStrut run under each bedside top rail, making a lifting device (similar to a bed lifting tool).

I need to rebuild the lower A-Pillar and lower B-Pillar first and foremost, so I can also use these points to jack or to fit rockers so doors shut properly.

I am using lower door hinge bracket as a front jacking point as this is reinforced.

I need the B-Pillar rebuilt so I can maybe jack here.

I figured if I built a bed lifting device, I could rebuild B-Pillar if I ran jacks to ground somewhere in the front floor area; no pans installed. And my other jacks just outside the rear bumper where the tailgate would be. This way doors will open and close for testing.

Idk, I don't see them move all that much really. Not considering how much adjustment there is in the panels and body mounts anyway.

If it were me, on a K5, I'd probably take the top off, and lift from the bed. Get any bow out of the fender/door/cowl area, have that all line up and equal, then pull the doors with it hanging, and brace A pillar to B pillar on each side, and B to B cross car.

Then make my repairs.

Hi - awesome project ! just having the determination to see it through to the end deserves a medal in itself - your Blazer will thank you !
I have one the same ( condition ! ) - some suggestions :

* if the frame is solid ( ie. not snapping in half from rot ) - use that as an acceptable "jig" for your repairs - the suspension will help to take out any distortion from your driveway.
* Remove the front sheet metal, doors and roof to get weight off the body.
* Don't try and lift the body off, as the firewall section is heavy, and with all the floor and bracing gone it will tweak you windshield frame and bust the glass etc.
* replace the rubber body mounts with solid ones temporarily ( can be made up with aluminum pucks from harbour Freight / Temu tool section etc. )
* repair the A and B pillars first as they are not attached to the floor yet, so will not mis - align the door shuts
* make sure to match the original sheet metal thickness ( eg. 20/ 18ga. ).
* Dont' try welding on super heavy diamond plate etc., as it will only cause fractures in the thinner sheet later on
* clean up all your floor area and test fit the new floor ( suggest getting an original cut from a wrecked suburban if you can, otherwise repro panels are available )
* level up across the bed floor and along the bed sides using this metal as shims under the body mounts and spirit levels, to get the rear body square as a reference.
* re-hang the doors and tweak / shim the front firewall / A pillar area to adjust the front windshield and read door gaps as best you can ( they were never perfect from the factory ).
* fit the floor and tack weld in, whilst checking the door gaps as you go.
* once fully welded in floor, replace any under floor bracing
* replace outer sills
* remove and replace solid body mounts with rubber ( I don't like the urethan ones - they don't hold up over time and lead to body sagging )

Your photos and profile show an '88, so am assuming it is a "half roof" blazer, so upper bracing across bed or doors is probably not necessary, and rear roof misalignment is unlikely to be an issue once replaced - although you could check as you go by replacing it and checking gaps - but it is heavy.

- Good luck and keep posting pics ! ..