Thanks; so when I look at the W124 alignment specs and see caster listed at just over 10 degrees, that's assumed to be negative? I think mine measured at just under 10 degrees (9.7 or so as I recall) after my last alignment, and I am having centering issues. I have tried loosening the steering box already, and while there is now more play, it still doesn't self-center.

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

mine centered very well until I put wider wheels and tires on, do you have stock tires and wheels?

__________________

1982 300CD Turbo (Otis, "ups & downs") parts for sale
2003 TJ with Hemi (to go anywhere, quickly) sold
2001 Excursion Powerstroke (to go dependably)
1970 Mustang 428SCJ (to go fast)
1962 Corvette LS1 (to go in style)
2001 Schwinn Grape Krate 10spd (if all else fails)

Mine are a bit wider, but it did the same thing with the previous (stock) size tires. Does yours not center at all now?

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

it centered perfectly with my previous ones. now it get close but is usually off to one side or the other depending on which way it is returnng.

__________________

1982 300CD Turbo (Otis, "ups & downs") parts for sale
2003 TJ with Hemi (to go anywhere, quickly) sold
2001 Excursion Powerstroke (to go dependably)
1970 Mustang 428SCJ (to go fast)
1962 Corvette LS1 (to go in style)
2001 Schwinn Grape Krate 10spd (if all else fails)

Thats pretty much what I have as well. I assumed it was time for a pump rebuild. Happened like this before and after alignment.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

I should have said "positive" caster in my original post, which has now been corrected.

It's the caster angle that is primarily responsible for steering wheel return. There is no other mechanism that causes it to happen, although there are plenty of opportunites for problems in the steering system that could interfere with the return to center.

Makes sense -- thanks for the help, and for the follow-up!

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)