Crossmember over rear coil spring and frame rust

[Atown]

Hello all-Recently got a 1971 c10 longbed that I’ve since converted to a short bed. While it’s been apart I’ve noticed some heavy rusting where the rear crossmember and the bottom frame rail are riveted together. It’s also bad where that reinforcement piece inside the frame rail sits. Ive tried doing some searching on the topic but haven’t found anything definitive on the subject. Does anyone have any suggestions on the fix? Is it better to find a section of frame to weld in or can I replace sections of the fram rail? Thank you in advance.

[AussieinNC]

Rust outs in this area are fairly common...

Post some pics of the areas of concern so we can see what you are facing...

[Atown]

Both sides pretty much look like this.

[AussieinNC]

That does not look all that bad....not the worst I have seen...

Jack up the rear of the chassis until shocks are fully extended and place jack stands under the chassis rails in front of the rear axle.
Place jack under differential and take load off of shocks...remove lower shock bolts
Remove the upper spring bolt and lower spring retainer bolt...these will test your patience....

Drop rear end down and remove springs

Grind off all the rivets holding the spring perch plate to the chassis and remove the plate...

Grab a wire wheel brush and clean up the entire area and the spring perch plate...then grab pics of the chassis area inside and outside,,,,and the spring plate from both angles, then post them back here...

The chassis will most likely be rusted away on the lower flange inside area...which can be plated with flat bar....

The spring plate will most likely need a new external lower surface repair...again, with flat plate...

Note...whatever you buildup on one spring perch plate lower area MUST be replicated on the other side to keep the support / ride heights the same.

Reassemble with grade 8 or better bolts, hardened washers and locking nuts in place of the original rivets.

[Atown]

Thanks I’m going to tear into this on Friday and I’ll post some pics.

[AussieinNC]

Take your time...especially with the upper spring retainer bolts and nuts...