The lower control arm bushings work within a certain range when locked down. The torsion bar is connected to the lower control arm via two bolts and provides tension on the lower control arm. If the TB is adjusted without loosening the lca bushings at the time of adjustment, you are dealing with opposing forces. The TB is is pushing the arm downward and the bushing is counteracting it because it is not in a resting state. It is torquing the arm upward in order to achieve the resting state of the bushing. It will wear prematurely because it is binding, in addition to squirrely handling.
When I adjust my TB's, I loosen the lower control arm bolts while in the air, adjust the TB's, lower the vehicle (the lca bushings will move into proper position at this point), then lock down the control arm bushings on level ground once the height has been achieved. The bushings are now in a "zero" state with no pre-load. Then the alignment can be done.
Apologies in advance for digging up an old post, but I cross levelled the front of my 2000 LX470 today and this part really confused me. The driver's side was a bit low (not much, only about 1/2") so my plan was to only crank up the driver's side torsion bar until they were even. (Tomorrow I'm planning to connect the VCI cable and read out the neutral pressures in Techstream and adjust both torsion bars evenly until it's in spec).
After first soaking everything in PB Blaster, I tried loosening the 30mm hex nut on the rear bushing. 3 foot breaker bar...nothing. Snap-On MG725 1/2" air impact...nothing. So I tried the hex nut on the front bushing...exact same result. Then I tried the impact on the front bushing bolt instead of the nut, and it loosened instantly. It threaded out very smoothly. I went back to the hex nut, and it STILL wouldn't move. Both of them are acting exactly as if they are welded to the lower control arm. I can't see any visible welds, and the 2004 Land Cruiser factory service manual (I don't have the 2000 LX470 manual) shows these hex nuts are separate pieces. Maybe they have lugs or some other type of interlocking feature that keeps them from rotating, but allows them to come off once the bolt is completely unthreaded.
But in either case, how do you loosen the REAR bushing when the head of that bolt is covered underneath the torsion bar? I can't find any reference to torsion bar adjustments in the 2004 LC FSM, but it does specify that the torsion bar is to be removed before removing the lower control arm, for what little that's worth.
Anyway, I tightened the driver's side torsion bar 4 rotations, measured, and then 4 more rotations. After tightening the front bolt back up, lowering it to N, and driving it, I remeasured the front ride height and now the driver's side is only about 1/8" lower than the passenger side, which I'm quite happy with. I took it for a 34 mile test drive afterwards and it felt great, no odd handling behavior, but I'm still a bit concerned about that rear bushing. Plus, I'm going to be adjusting both sides again tomorrow.
Certainly I could remove both torsion bars, loosen all four bolts, set the cross leveling as close as humanly possible with hydraulic jacks, then tighten the bolts, reinstall the torsion bars, and set the neutral pressure with Techstream, but that sounds like an insanely overcomplicated way to cross level the front end and nobody else has mentioned anything that involved.
torsion bars are original. However instead of conventional dampers I installed coiled shocks for the reason that I won’t have to replace torsion bars. Vehicle already had them when I bought it so I replaced them with the same ones. Height was okay after the replacement as well but I screwed up by touching the torsion bars now I’m just trying going back to the same height. Since there’s too much tension on the shocks/squished too much they aren’t performing well
