W124 Front End Rebuild

[Chris Blanchard]

One of my front susp. springs has broken down near where it mounts into the control arm, so I must replace it (and the other side as well).

I am considering replacing the entire front end myself, as having my good mech just replace both springs would set me back about $500. I've priced out the parts (ball joint, spring, strut mount, bilstein strut, control arm, eccentric bolt kit, control arm bushings, bellows, bump stop, - the whole nine yards).

I am debating whether to replace the control arm completely, or just replace the ball joints and bushings. Considering the paid labor to do the ball joints (I estimate $60 total) and the work to replace the bushings, I am considering spending just a bit more money and getting all new control arms which already come with that stuff.

It would cost a bit more, but would save me a good bit of work and two trips to the machine shop.

Are there OEM control arm manufacturers to seek out? Avoid?

Please advise. (Yes, I know I have to rent the MB spring compressor).

Any thing else to consider - tie rods? what else?

How much extra would going "sportline" add to the total bill. I do plan on replacing the rear end this fall.

(Also am considering rebading my car as a 250D, as that would be the correct euro badge - maybe after I install the Euro lights later this year).

Chris Blanchard
1992 300D 2.5 Turbo 160,002 miles
Cincinnati, OH

[md21722]

New dealer control arms are convenient, but most costly. Folks have borrowed the AutoZone ball joint tool and got it to work for the most part. Bushings can be chiseled/beat out or burned out. New bushings can be pressed in with a vice or creative use of threaded rod and sockets.

I divide suspension work into (a) needs springs compressed and (b) does not need springs compressed. The steering linkage - tie rods, drag (center) link and idler arm do not require springs compressed. However, it does require and additional alignment and the parts are only about $150. If your steering linkage is looked tired (loose, busted boots) I'd replace it to save an alignment later.

[csnow]

Up to you on the whole arms. $$$ vs. convenience. Time vs. money.

Honestly, if you have a decent vise, you can avoid the machine shop.

The balljoints knock out easily with a big hammer.

If the bushings give you trouble, you can drill a hole through the face of one bushing, and use a punch to knock the other one out from behind. The second bushing is always easy enough.

I use a big hammer and a pipe fitting to install the balljoints. Helps to put them in the freezer first.

I use a pipe fitting and the vise to install the bushings. Be certain to orient the bushings properly, as specified in the shop manual.

I would have to look, but I believe my special "bushing install tool" is a 2in steel pipe coupler with some of the female threads ground out. I put a steel cap on the other side to give the vice something better to press on. Anyways, just a few dollars at the hardware store.

CA rebuild is quick once you know these tricks.
Best of luck.

[Chris Blanchard]

Ok, I think you guys have convinced me to deal with the ball joints and the bushings myself. I've put together several home made "tools" to do various jobs on my old W126 (trailing arm bushings, subframe bushings, etc) so I'm sure I can scab something together for the bushings.

It's just that the ball joints on the W126 are such a ***** to deal with. Does the W124 have the same "angle/offset" to deal with that makes regular ball joint tools not work? For me, that's the
real deal killer in all of this. My machinist reamed me for getting those old ball joints out in my old W126.

Please assure me that we are dealing with a different way that the ball joints are mounted and I'll be sold doing the job myself.

I do have really heavy vise (30lbs or so) and that could be useful.

Thanks!

Chris

[csnow]

Yes, they have an offset, probably similar to the one you describe. While I'm sure it can be dealt with, the big hammer works so well for removal that messing with anything else is a waste of time IMHO.

[samiam4]

If you want an improvement..

You can add sport line swaybars to your list=) There are a few dozen spring compressors in group member's hands. Maybe you can find someone on the list in your hometown(?).

Yep, sometimes the lower coil breaks off. I have yet to tackle this job on my newly acquired W124, but I'm not scared. The rear suspension gets done first, right after the cold start, new headlights, seat, carpet cleaning, wiring, cruisecontrol by August, and tinted windows before it gets hot!!

Funny how these nearly free perfect cars can take $$$=)


Michael

[dtf]

If your front suspension is the same as my 1994 the ball joints are part of the control arm and can't be done independently. I'm probably wrong though (ask my wife ):p

[samiam4]

On the lowering thought...

If you decide to use shorter springs, consider the factory sportline stuff. They also make a different parts so you don't endup with the bump steer feeling.


Michael