Upper control arm replacement on '80 300D
 

I need to replace the driver's side,upper control arm on 1980, Mercedes Benz, 300D. My technical info is fairly complete (CD from Mercedes), however, it recommends the use of an extractor to separate the ball joint and the use of a 'spacer' to install the new control arm. I have a fork type ball joint separator (used with a hammer) to force the ball joint appart and wonder if this would not suffice. I don't understand the need for the 'spacer' to install the new ball joint. Can't I just tighten the ball joint nut to seat the ball joint properly? I also need to replace the bushings (rubber all broken out - metal rubbing against metal) on the mount (perhaps not proper term) that connects the control arm to the body and the torsion bar bushings. How hard will these bushings be to get out? To replace? Any suggestions/tricks? The torques for these three fasteners (ball joint nut, torsion bar bolt, body mount bolt and nut) seem rather low? Any lubricants (e.g. anti-seeze) needed on fasteners or rubber? I've been saturating the fasteners with penetrating oil for the past couple days.

I only need to replace the driver's side control arm but also plan to replace passenger side (marginally bad). Any problems with replacing upper ball joints and not lower ball joints (they are OK)? Is it recommended to replace the body mount thru bolt and the torsion bar end bolt. I was not planning on replacing these, however, I have not exposed these so at this point I'm assuming they are OK (they are probably original and mileage is 250K).

Parts ordered:
Two upper control arms
Four body mount control arm bushings (one on each side of of each arm)
Four torsion bar bushings (one on each side of each arm)
Two ball joint nuts

Tools:
Fork type ball joint splitter.



Any and all pertainent suggestions/tricks would be greatly appreciated?

Somewhere in the archives are some posts on replacing the upper arms. I did them on my 83 a few years ago, without any special tools. The fanciest that I got, was two floor jacks.
The new bushings in the arm may want to fight you when the time comes to put on the big bolt and washer. I have not done the bushing for the stabilizer bar, but from what I remember reading, it's a bear.

Good luck!

I've done quite a few of these, a floor jack and a support jack should serve you well.

I've even replaced one on the side of the road (on GRAVEL!) with only two MB jacks to assist me, don't ask me how... I don't recommend trying that :rolleyes: