Replacing Track Rod Mount

[dieselnewbie]

Hello all,

This is my first time posting so please bear with me. My 1982 300Sd (203740 miles) recently started to pull hard to the right while driving. The left front tire had signs of severe wear on the outer edge. I have switched it already with the spare due to my concern for tire blow out/failure. At first I thought it had to of been an alignment problem, but the severity made me think it might be something more. I took it to a trusted alignment shop where they inspected it for me. They told me there was too much play in the track rod joints and I would have to replace them. They wanted $500 for parts and labor (which is ridiculous), so I’m going to try and replace them myself, possibly with the help of my dad. Now I am not an experienced mechanic (unlike my dad), but I'm trying to learn as much as I can about my beautiful 300SD. I recently changed the oil all by myself, which to most isn't that big of an accomplishment, however I see it as a step towards my personal growth as a mechanic. So my question is: Does anyone know the steps involved in changing out track rod joints? I would appreciate any tips from you all very much. Thanks so much! I can tell this message board will be a valuable resource!

Alex

p.s.

I have attached a photo below. I am going to replace part #13 on the chart.

[engatwork]

The easiest way to do it is with a coil spring compressor but it can be done without removing the coil spring. After you remove the fasteners from the track rod mount you are going to have to use something big and strong (hydraulic ram or really long crow bar comes to mind) to ease item 14 toward the front of the car to get enough clearance in there to remove/replace the mount. Just take your time and make sure whatever is holding the car up is secure prior to doing this work.

[leathermang]

Where did you get that pretty drawing ? Are more available for the rest of the car / engine ?

[MikeTangas]

Leathermang,

those drawing are from the Performance Products online catelog, the one really nice thing they have.

DieselNewbie,

A come-a-long around the lower control arm will work fine, just make sure it is anchored to something solid and work slowly. I found when I did mine a couple weeks back that once the two main bolts holding the bearing bracket to the chasis were out, the whole assembly would drop down about an inch. At the same time it drops, the complete front assembly, on the side you are wokring on, will shift toward the rear.

I only attached the come-a-long after everything had shifted and I couldn't thread out the rod any further. What happens is the rod on the mount is approximately 3 inches long, and as you unthread the bearing bracket assembly moves back until making contact with the chassis. At that point I would pull the come-a-long one click, then unthread some more. I think it took me about 4 or 5 clicks on the come-a-long to get the mount out of the rod. Like I said, work slow - one click at a time. You don't want to suck your car right off the jack stands.

[william rogers]

I also used a come along when doing track rods on my 81 SD and 86 SE I attached it to the tow hook on the passenger side and can't remember where on the drivers side ,but make sure you got a good hook up and be carefull as it's a job with some potential danger.........
William Rogers.........

You really need to get the manuals from Mercedes if you're going to do work on your car. Please be extremely careful working around MB springs. They can be fatal if you aren't careful. Don't even try to remove one with those cheap aftermarket hook type spring compressors. As was said, you can do this job with the spring in place, but it is easier with the spring out of there and I bet there are other parts in that front end that need to be replaced too and the spring needs to come out for them.

Len

[wbain5280]

You may want to replace it's friend on the other side as well. It's best to do suspension work in pairs. I've learned this the hard way.

[MikeTangas]

Shouldn't be any worry about the springs - as long a sthe steering knuckle is still attached at the upper and lower ball joints. That will keep the spring confined within the perch and seat. I would also replace both mounts as was suggested.

[dpbrowne]

Great picture. I had a personal question. I do not want to take away from the help you are getting but I noticed that on the part labeled #3 on my car the bushing seems crushed. Should it be like that. 1983 300SD

[engatwork]

Part #3 is the upper ball joint rubber cover. If it is crushed I would seriously consider replacing the upper ball joint. It includes the complete arm and is pretty easy to replace.

[dmorrison]

This is what a new upper ball joint looks like in a 123.

Dave

[dmorrison]

Photo 2 of upper ball joint, brand new.
Does your ball jont look like this? Is the rubber boot torn or cut?
If the boot is fine and the ball joint looks like this then its probably ok.
Dave

[jcd]

Both guide rod mounts on my 1977 300D are shot, as well as the bushings for the attachment of the guide rod to the lower control arm.

As a result, I am going to rent a spring compressor and so a semi front end rebuild, new guide rod mounts, upper control arms, lower control arm ball joint, new drag link, bushings, etc.

I have also read the "replace the springs or not" thread and that is my quandry. My sense is to check the ride height, based on manual specs, and see if they are needed. However, the springs are original and for the $ I might just make the plunge while I have the spring compressor rented.

Any thoughts or advice is appreciated on this effort....but I have gained alot of info already via this thread and others that I have picked up via searching.

Great site.

JCD

MB springs last a long, long time usually.

Len

How can you tell if the spring need replacing? How long do they normally last?