Originally Posted by mad55chevy
I have a '55 210, and I use the stock control arms, upper and lower. I have done my homework here, and have all new poly bushings, a pair of offset upper control arm shafts, new heidt's spindles, stock new springs, and a nice new rack & pinion.
Currently, my castor is maxed out at -2.5 degrees, both sides. I have stuffed in as many shims as I can, and at least it's matched both sides. the offset upper shafts only gave me a degree. Obviously, this is why the car handles poorly at high speeds, and bumpsteer is real bad. It is my quest to get more castor, and a lot of it. I just ordered new upper control arms (tubular) that have 6 degrees built in..hooray.
what in the world can be sagging?? front crossmember? front half of the frame? All looks OK on the frame, looking for clues as to why this came to be.
I had the same issue (lack of caster, much bumpsteer) with my '56 Bel Air. The upper offset arms helped however I found the lower control arms had been moved out an inch and the crossmember drilled for the control arm bolts.
Perhaps the lowers were relocated on your '55 and the original holes were welded shut. I caught mine by sighting the imaginary line from upper control arm bushing to the lower control arm bushing. In that line the inner tie rod joint should fall and mine didn't. Fortunately the original holes for the lower control arm were there.
A higher ride height in the rear will reduce true caster. Might be a consideration.
An old time alignment guy told me these cars had the same problem when they were new. He'd go to NAPA and get the off set uppers for $15. Way higher now aren't they?