Home-made $15 W124 LCA Bushing Tool

[Jeremy5848]

Sixto has written an excellent guide for replacing W124 LCA (Lower Control Arm) bushings here. I was replacing the Lower Control Arms on my '87 300D Turbo (W124, OM603) because one of the inner bushings was bad. I discovered that I also needed to replace the outer bushings, which are pressed into the wheel carrier. Unfortunately, I did not have the expensive tool needed to remove the old bushings and install the new ones and decided to build my own tool. This tool, or something similar, probably will work on other models of Mercedes.

Sixto's thread has excellent pictures of the commercial tool. I made a trip to the local hardware store and managed to make my own tool from three galvanized steel pipe fittings and several 1/2 inch bolts, nuts, and washers. The total parts cost was about US$15.

Parts List with cross-reference to part names used by Sixto to describe the commercial tool

A. 1 each 1-1/2" x 2" nipple (dual-purpose "removal receiver" and "installation receiver" Note: see text)

B. 1 each 1-1/4" x 2" nipple ("installation drift")

C. 1 each 3/4" coupling ("removal drift")

D. 5 each 1/2" bolts in sizes from 5 to 7 inches (Because the bolts at the hardware store were not threaded all the way, I had to change to shorter bolts as the bushing gradually was pushed out or in. With a bolt threaded all the way, only one is needed.)

E. 2 each 1/2" nuts (one to use and one to lose)

F. Assorted 1/2", 5/8" and 3/4" washers (they bend if you use only one)

The head of the bolt and the nut both take a 3/4" wrench. I used a 1/2" ratchet and a deep 3/4" socket on the nut plus a 3/4" combination wrench to counter-hold the head of the bolt. I put some anti-seize on the threads of the bolt(s) to reduce friction. These were normal coarse-thread bolts (13 threads per inch, I think).

To remove a bushing from the wheel carrier you need parts "A" and "C" plus two or three of the bolts, some washers, and a nut. In the next two pictures, the parts are pictured individually and as they were used, with the old bushing in the middle. Part "C," the 3/4" coupling "removal drift" was just small enough to go through the hole in the casting. That was just luck. As you tighten the nut, the head of the bolt pulls part "C" and the bushing out of the wheel carrier and into part "A," the "removal receiver."

Note that part "C" is not as slender as the real "removal drift;" it can damage the bushing as it works since it presses on the inner part of the bushing as well as the steel outside. Since the bushing being removed is presumably bad anyway, this does no harm but I do not advise using this tool to remove a good bushing. It might damage the bushing, it might not. Yours is the risk to take.





The next picture, a double image, shows the front and back sides of the casting in which the bushing mounts. The casting is part of the wheel carrier and the pictures show the tool in the process of pushing the old bushing out.



With the old bushing out, I cleaned the hole in the wheel carrier with steel wool and lubricated both the hole and the outside of the new bushing with anti-seize compound. Oil or grease, anything slippery, would probably work just as well to ease the bushing into its new home. Here is a picture of the installation tool.



The installation tool is made from parts "A" and "B," plus the bolts, nut, and washers. Part "B" is another lucky piece - it's the same diameter as the outside of the bushing so it can push on the bushing without damaging it. Unfortunately, it's just a bit too big to go through the hole in the carrier or it could be used for removal also.

When I tried to use the installation tool, I discovered why the "installation receiver" in the commercial tool has an edge cut off (see the pictures in Sixto's thread). It turns out that the front side of the wheel carrier has a reinforcing boss that gets in the way of the receiver. My receiver (part "A") was too large; I needed to cut about 1/3 off of its length and then cut an edge like the commercial tool.

Rather than do that, I decided to use part of a 1-3/4" chassis punch as a substitute "installation receiver." It fit well enough that I was able to use it without modification, saving me some time. This assembly is shown in the next two pictures. The piece from the chassis punch is on the left side. You may not have such a thing, in which case you will have to use a hacksaw on your part "A" to make it work.





Since the home made tool does not center the bushing as well as the commercial tool, you have to make sure the bushing is going in straight. My first try was cock-eyed and I had to stop, remove the bushing, and start over. The second try everything went well. Here is the newly installed bushing.



With the new bushing in place, it took only a little more time to install the new LCA and button up the suspension. Tomorrow I'll do the other side. Wish me luck!

Jeremy