rear frame repair

[pwdcougar]

Posted this on my project/build thread in the 67/72 Suburban forum and though I'd post it again here in hopes that it would get more response. The ends of the K10 frame were cut off and the body mount holes are badly rusted.

The truck is a 70 K10 Suburban and the patch piece is from a C10 Suburban.

Cut the rear frame portion from the 68 today in the pouring rain so I can repair the rear section of the 70.

Any recommendations on welding this on? I was thinking of the following steps:
1) remove the rear shackle mount

2) make wood braces under the existing frame in 3 or 4 locations to orient the frame for alignment. Locations for the braces approximately where the yellow X's are.

3) cut the original frame and replacement frame at the same point.

4) butt weld inside and out

5) use my extra steel to fish plate inside the frame

6) re drill the shackle mount and bolt back into place with grade 8 fasteners.

Any suggestions? Should I post this on the truck section or someplace else?

Thanks

Paul

[pwdcougar]

Hmmm no takers on my plans. Time to change them then!

Been thinking about cutting the frame and putting it back together at a suspension load point. Now I'm thinking that it will be better if I cut and patch behind the rear spring mount so it is not a stressed suspension point. New cutting location will be at the red line in the picture. My fish plate will now be longer and I'll run it past the spring mount. I'll drill out the rivets and drill through my fish plate and also weld around the whole plate.

I really wish that someone would give me some feedback. I've never done frame work before. My past restoration projects were unibody cars.

Paul

[dwcsr]

I would only replace whats bad. If the area in the box is the only bad spot replace just that area. From the patch frame cut 4 squares like in fig A. weld them at the patch seam on both sides of the rail just as they are positioned, in a diamond shape. That's it your done in 2 hrs. max

[NEWBIEC10]

X2! Don't take more than you need to.

[pwdcougar]

Thanks guys that makes sense. How about the repair on the left side with the rusted body mount hole?

Paul

[dwcsr]

Cut that area out and replace it as long as the frame under it is not rotted or badly pitted

[pwdcougar]

Got it! Thanks Dave

Paul

[chevyguy_72]

I have always read you should do a Z shaped cut vs a straight butt cut and weld... then welding the diamond shape on for extra support as well... I have seen this when several are doing a lwb-swb conversion... makes sense though... spreads out the area and angles of pressure... and agree with all above... do as little as possible... unless its badly pitted or rusted and I would try at all costs to stay out of that rear suspension...

[CURSED GEARS]

Hey PWDCOUGAR! Old thread I know, but how this turn out? I'm looking at repairing or replacing my frame, and was googling frame repair. How it turn out?

[pwdcougar]

It turned out really well. Decided to cut the frame at an angle on each side. On the right it us just butt welded (from each side) and on the left it has a gusset or fish plate on the inside. The left was cut in the middle of the leaf spring support. The spring support got bolted back on with grade 8 bolts through the gusset/fish plate. Old school truck drivers told me that welding straight up and down on a frame isn't a good way to go. The gusset plate went on the inside of the left and was shaped like a trapezoid. /_____\

I got the frame set up level in my garage with a concrete block and wood support and took lots of measurements for alignment.

Paul

[CURSED GEARS]

Looks good. thanks for replying!