Originally Posted by Gordon Nichols - Massachusetts 1993 CMC:
Actually, you're looking at adjusting the wrong end. The front trailing arms are probably fine. You adjust the fender height (even in the front) by adjusting the REAR height by moving the spring plates on the torsion bars. There mit be a write-up in the knowledge section on here. If not, email or PM me and I'll send you complete instructions.
gn
To add to that, if the ride height was set level with simulated driver's weight in the seat by reindexing the rear torsion bars, it can sit a little lopsided (left rear high, right front low) without anyone in the car. Jack the front end up in the center of the beam to create a balance point, both front wheels off the ground, and see if the rear is level left to right. It's a quick check to see if the rear is indexed close to even without needing to disassemble things.
As Wolfgang said, if the sagging problem is actually with the front torsion bars, it's most likely a broken leaf. The grub screw on the arm only prevents side to side movement. The trailing arm itself is shaped internally to fit the stepped shape of the leaf spring pack so the arm cannot rotate around the spring pack even if you remove the grub screw. (Not enough to visibly affect the ride height anyway, unless the hole's horribly wallowed out.)