View Full Version : Out, OUT, foul rot!!
Had a fuel tank strap come undone on the 88, 3500. Turned out that the strap fits though a keyhole in the crossmember and it had pulled right through and not just rusted off. Here's the hole in the crossmember where there once was solid metal. This is the left end of the crossmember where it hooks (used to) to the lower frame rail
The other side was just as tender. I ground the rivets off and when I tried to punch them out the whole crossmmeber crushed down at the bottom instead of the rivets punching out. The gap between the top of the crossmember and the frame shows how far the c'member crushed from just a hammer and punch.
The rear c'member, where the spare tire winch is mounted was as bad. Good thing I didn't have a spare hanging on there or it would have been on the ground. There's a major hole where the outline is and a worse one on the other side.
A junkyard run snagged a section of frame with good crossmembers. A little time grinding out rivets and chipping rust got me two sound c'members. I sprayed them liberally with rustproofing and let them set in the sun for a day to tack up some.
The new (newer) c'member is in place over the fuel tank and everything is coated with another layer of rustproofing, especially the sending unit area. Now I know it will come apart, if it ever needs to, without wrecking the tank. I reamed the rivet holes to take 1/2" bolts, no way I would mess with rivets, even if I could find them.
With a solid rear crossmember in place I'll finally be able scrounge up a spare tire winch and have a spare with me all the time.
The right shock support was also trash, a victim of rot and too many heavy loads. You can see where it came apart in the picture. It had torn completely in two and was too thin to even consider trying to repair it. I had one out of the donor frame but they changed the design along the way so it wasn't usable.
Being a bit of a fabricator I made one. It's all done in 3/16 plate and many inches of weld bead. I tacked the pieces together so I could make a jig to locate the shock mounting holes in the correct places. I primed it right after I took the picture, tomorrow I'll hit the mating surfaces with rustproofing and bolt it in.
Working between showers (it has rained five times today, not counting sprinkles) this job is dragging out way longer than I had planned. Oh well, it will be sound for this winter. While the box was off I have also installed new cab corners on both sides. I also took the time to chip the rust scale off the frame and rustproof that completely.
I had to drop the running boards to get at the cab corners. On the drivers side I happened to look at the bottom of the frame and found this. I had fixed cracks in the top of the frame last winter but I never stuck my head underneath to check there.
Should have!
I'll play some games with clamps and jacks to get the cracks to close up, then weld them, grind them smooth and plate the whole area. I think I'll also be coming up with braces like Fisher used to run that will take some of the flex out of the frame. I may get a jump on the other side and plate it now, before it starts cracking.
I do love my GMs, but there's not much excuse for the frame being as thin as this one is. It's a bigger section but the material is not much thicker than the frame on an S-10.
Alan,
My fuel tank crossmember is doing the SAME thing. Mine is probably worse! Me seeing this prompted me to get a new truck. Still have the '90, but will need to do what you did sometime soon.
Any other suggestions as to finding a c-member other than a junkyard?
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