New to me '85 359

You could replace the frame rails. I replaced the frame rails on a 77 Pete years ago. It was an interesting project. The company bought the new rails from Freightliner. Saved a lot compared to rails from the Peter built dealer.

 

More than we want to tackle. Next guy can explore the options...

 

Frame stretches need extra cross members. That is nowhere near the cost of rails, would help but is likely to late it yours are already cracked.

 

If any of you remember the KW torsion bar rear suspension, although they were comparable to an air ride and lighter weight, the cost of parts to overhaul them was so high that I was able to install Reyco four spring suspension at a lower cost. I was also able to install the three Reyco cross members without removing the original torsion bar's cross
members. The strength of the frame was increased substantially.

 

My '80 W900 had a factory double framed portion where the rear suspension bolted up for extra strength. It was rust jacked so bad that it cracked the left rail on the curve between the upper flange and the web. I kid you not there was at least 1.5 inches of rust flake between the lower flanges. Wasn't a bad deal to torch the bolts off and beat the inner rails out. In my case I could have easily just welded the rail, sandblasted the rust off and installed a new reinforcment sleeve. Would have probably cost me maybe $3k to do it myself. I decided to replace the rails from the cab back because the original rails were full of holes from previous owners.

 

Very nice not often you see budd wheels on Peterbilt steers.