Vehicle is 1983 300TD on which I just finished rebuilding the front suspension, from anti-sway bushings to new UCAs, new LCA ball joints and bushings, brake rod supports and shocks. Also, tie rods, drag link, and steering shock.
I first installed the new brake rod supports on the frame to the identical lengths of the ones removed. When I then installed the LCAs, putting the eccentric washers in their previous orientations, the bores in the end of the brake rods were far from concentric with the bores in the LCAs, so I shortened the guide rods by two or three turns each until the bores were concentric, installed the conical bushings and discs, and tightened things up--the LCAs had free unimpeded motion through what appeared to be their range of travel.
This is probably a stupid question, but it is not clear to me how the brake rod can now also be used to adjust the caster since it appears to me that lengthening or shortening it will place a front to back bending moment on the LCA bushing mount which, tightened to 180 Nm, does not move much, if at all, in that direction.
I ask this question after taking the car to a shop for alignment and being advised by the tech that he could not get the camber to 0 degrees, both sides being slightly positive with the eccentric washers locating the bolts in their far outboard positions. The tech thought this was because the rear end was too low--admittedly, it was sagging badly because the sls valve is leaking down which I have ordered a repair kit for. So I have now read enough in the FSM on caster and camber to be somewhat confused, and wonder if my shortening of the brake guide rod may be contributing to the problem since in doing so I reduced caster and increased camber. The FSM shows a special tool for doing a basic adjustment of caster by setting a 14mm gap at the guide rod support--I suspect that mine are at less than that since I shortened them.
The shop offered to re-do the alignment for free when I get the low rear end fixed, but I would like to understand the issues better before I go back.
What am I missing about adjusting the caster using the brake guide rod?
Peter Ferguson