Steering / suspension advise needed - Page 2 - PeachParts Mercedes-Benz Forum

Maxbumpo · #16 04-07-2015, 03:51 PM

If the ball joint is bad, odds are good the other side will fail shortly, especially if you've got some bad tie rod ends.

MB says if there is any play in the ball joint, or if the grease boot has been compromised, the joint must be replaced. Ignore this at your peril. If the ball joint fails, the entire front wheel assembly can come off the car and the car crashes. This crash may injure or kill occupants of your car and any other cars or pedestrians that may be involved.

One philosophy is to replace entire assemblies, and the more I work on suspension, the more I am moving toward this philosophy.

There is a related school of thought that says when you do any major suspension work, do ALL of the suspension wear components and rubber at the same time for that end of the car, which will savee you some labor hours and potential grief down the road. Only pull those suspension springs once, only pay for one alignment.

Ball joint bad? If the rubber parts of the inner bushings are cracked, and you're going to get an alignment, try adjusting the eccentric bolts (I'll bet they are corroded in place). Any suspension / engine mount rubber with more than ten years / 100k miles of life is suspect. If your inner bushings have issues (and I'll bet that they do) then consider purchasing new lower control arm assemblies from MB, which come with new ball joint and new bushings installed. I know the Northlake dealership in Charlotte NC sells them for about $300 each, and you won't have any quality worries about chinese-made stuff. The original parts lasted over a decade, why buy something that is probably inferior and may only last a few years?

I've replaced the inner bushings on two 124 cars, and it is a lot of time and requires more special tools (chiefly a REALLY big C-clamp and a saw-z-all). One both cars I found corrosion inside the bushing hole(s), and so had to spend significant time grinding out the rust and then painting and letting that dry. How much rust until the strength of the control arm is compromised?

Replacing just the ball joints also calls for special tools to remove the old joint and press in the new.

Save the cost of renting or purchasing the tools, just get new control arm assemblies from MB. I've heard some horror stories about the assemblies from Febi, no experience with Lemforder assemblies but why risk it? I hate suspension work, don't want to repeat it any sooner than necessary, so now I buy all my suspension parts from MB unless there is some overriding time constraint that forces me to purchase from FLAPS.

There are similar issues with the tie rod end vs. complete assembly - save the time / money and get assemblies. If you want to keep what appears to be good, take the time to ensure the adjustments are not corroded in place; you don't want the alignment shop to call and tell you they can't align your car without replacing the other tie rod assembly or joints. In your place, I'd do all of the following:

- Complete lower control arm assembly with bushings/ball joints installed (get all new hardware too: eccentric pins, bolts/nuts for ball joint pinch joints)
- Rubber shims on top of suspension springs
- Left and right tie rod assemblies and center drag link
- Steering shock
- Idler arm rebuild kit
- Sway bar rubber bushings

While you have the control arms off, great time to also pull the struts out and test them in accordance with the factory test in the service manual, which basically is compressing them a measured amount on a bathroom scale and reading how much force is required. If the reading is too low, the strut is bad. Might as well replace the strut mount (rubber) while your there, and don't forget the accordion boot and bump stop for the strut!

Before you know it, you've dropped an easy grand, all for a squeaking ball joint...