Quote:
Originally Posted by Derek UK
A good explanation from 142. With the 240, the lower outer front suspension joints are different for PAS and non PAS. This makes the caster different as mentioned. Any car that was not originally fitted with PAS might have it optimised for that. "Our" cars which have models with and without PAS may also have different joints. There aren't many of these and maybe Volvo didn't address this until the 240. Exploring the parts books might find something. It could be that different lower A arms could use the same ball joints to do the same thing but different ball joints would be simpler and cheaper.
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The 240 is a slightly different kettle of fish with the Strut front suspension. Caster is technically not adjustable so perhaps Volvo had alternate lower control arms with less 'designed in' caster to reduce steering effort. I have never driven a 240 without power steering and wasn't aware that they were produced.
The 140 parts book does list different lower A arms; but, they are associated with bias ply or radial ply tire fitment. 648765 / 648766 are for bias ply and 648767 / 648768 are for radial fitment. The only reference (non Volvo) that I have found indicates that the bias ply versions were fitted up to 1969; but, the parts manual does not indicate a change by chassis number so who knows? The references that I can find indicate that the recommended alignment settings did not change during the production run (at least up to 1972) so I don't know what the change in A arm for bias versus radial was to accomplish. The steering knuckle did change twice during the production run; but, these were all early changes before the production numbers got past 5 digits.
The parts manual does include the power steering option for the 140; however, as far as I could determine there were no suspension component changes associated with power steering.
Unlike the 240, the 140 with upper and lower wishbones and the shim adjustments on the upper wishbones is adjustable for both caster and camber. The service manual does not specify limits on the adjustability; but, I have seen pictures and read first hand reports of some pretty extreme stacks of shims, mostly in aid of increased negative camber. I went back and looked at my notes from my wheel alignment that I did on the car. Unfortunately, as much as I can decipher from my chicken scratches, I do not have a record of total shim thickness. I just recorded the initial camber and caster and the change in shim thickness required to get the results I wanted.
From my final scratches it appears that I ended up with a camber of approximately - 0.5 deg and casters of 1.6 deg (L) and 1.8 deg (R) with a final toe in of what looks like 2 mm. My stack of shims is modest compared to what I have seen which probably reflects my rather modest -0.5 deg of camber. At the end, I know I was fiddling with 1/32" shims to get the alignment values in the correct range.