Am getting a new upper control arm, just one, for an 83 300 D.

I assume that I'll need to get an alignment after this, right?

Can I get by without getting a four wheel alignment and just a 2 wheel job?

There is no such thing as a 4 wheel alignment on the W123, unless you happen to have adapted a GM Quadrasteer axle.

Not exactly accurate, but it's true that there is no such thing as a 4-wheel alignment on a W123 chassis. The rear end is bolted together with not options for adjustment. If it's out of whack, it's because something is bent, or the bushings/mounts are in need of replacement.

The same usually applies to almost all front engine / rear wheel drive vehicles to some extent. Most front wheel drive vehicles, on the other hand, do have 4 wheel adjustment provisions.

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- K.C.Adams

'77 300D Euro Delivery
OM617 turbo / 4-speed swap
404 Milanbraun Metallic / 134 Dattel MB-Tex

Current status:
* Undergoing body work

My '77 300D progress thread

Ok, I oversimplified. Still, there are no adjustments on the W123 rear suspension. Only replacement of worn/damaged parts.

There is on my W124

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Current:
05 E320 CDI
07 GL320 CDI
08 Sprinter
05 Dodge Cummins
01 Dodge Cummins

Previous
2004 E55 AMG
2002 C32 AMG (#2)
1995 E300
1978 300D
1987 300D
2002 C32 AMG(blown motor :[
1981 300SD
1983 300SD
1987 300SDL
2002 Jetta TDI
1996 S420
1995 S500
1993 190E 2.6
1992 190E 2.3
1985 190E 2.3 5-Speed

OK, on a 126 as well, but a 123, I'll go with FI on this.

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83 SD

84 CD

One can replace the rear trailing arm bushingfs w/ concentric ones, allowing adjustment. How you would figure out which way to install them is beyond me. they are pretty much only to correct bent or broken things which should prolly be replaced if bent or broken.

the main difference in 2/4 wheel alignmentt for our cars is how much of your alignment guys boat payment you want to make...

on a live axle RWD car, the axle can become out of alignment w/ the front wheels, usually the r side will get pushed back from running over curbs to many times. not very common, but can happen.

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.