I followed this video:
Here are the numbers:
Neutral height - Fender to center of wheel
FL: 19.5
FR: 19
RR: 19.9
RL: 20.2
Pressure test in Neutral
Attempt 1
Front: 8.6
Rear: 7.7
Attempt 2
Front: 8.8
Rear: 7.4
Attempt 3:
Front: 8.4
Rear: 7.7
Height control sensors at N: 0.0 (for all)
Gradation check between H and L: 8 (I didn't add the fluid back)
I didn't adjust the torsion bars but the high front pressure indicates I need to do that. The heights in the front are pretty even though. What should it ideally be, after adjusting the torsion bars?
The rear pressure is also high, and the gradation check seems things are within spec. So that leads me to believe the globes are fine but I need new springs in the back? That's what creating the crazy bounce? One more thing, both the swaybar end links in the rear are broken Dunno if that's contributing to the bounce.
Your post #17 and later posts shows that you are on top of things -- great work!!
Suggest cross-level a little more to equalise Left front and Right front using torsion bar adjusters, then make large adjustments clockwise (looking up from below) to both torsion bars to bring front pressures back into FSM range. They are way high -- expect a lot of turns on both sides at about 0.2Mpa per turn.
Rear AHC pressures also are way high -- probably will need replacement springs -- it is unlikely that pre-loading with spacers will cut it.
Torsion bar adjusters do not change heights on an AHC-equipped vehicles but only affect pressures - only the Height Control Sensor adjusters cause heights to vary -- because the self-levelling design of AHC system means that the ECU will cause the system to seek the position at which Height Sensor readings are near zero (inches or millimetres) at "N" height setting (provided the Sensors are healthy). [Actually, the signal from the Sensors to the ECU at "N" height should be about 2.25 volts but you don't need to worry about these details unless chasing down Sensor problems].
With AHC pressures corrected, an improvement in the HI/LO test could be expected -- there may be some life left in the existing 'globes'!!
The high AHC pressures Front and Rear mean that damping is heavily compromised -- damping usually is best with Front and Rear AHC pressures below mid-point of the prescribed range -- and the ride will be rough and abrupt until these are corrected and decent damping is achieved.
DEFINITELY sort the broken sway bar links and other bushes -- this situation cannot be helping. Also have a close look at the bushes in Rear upper and lower control arms and Rear shock absorbers. While thinking about bushes, also scrutinise all Front bushes -- control arms, sway bar, shock absorbers, everything.
There are few challenges as mentioned above but nothing out of the ordinary for a 17 year old vehicle -- seems like you have a great truck in the making!