Thanks to Anthonyb for documenting the W124 shock replacement. It really helped me get a better idea of what I needed to do before doing it. I am going to take his original write up and modify only the parts that I did differently. Hope you don't mind, Anthony
Tools:
Floor jack + jackstands (2)
1/2 rachet and 17mm socket
17mm open end/box end combo wrench
3/8" ratchet and 10mm socket
Grinder with cutting disc
Screwdriver
Vaseline
PB Blaster
1. Yank out the trunk liner panels. For the side panels, I found it easiest to start by pulling on the far (cabin) side first and bending them back. Remove them out of the trunk to give yourself some extra space to work
2. Loosen the lugnuts and jack up your car at the differential. Remove the tire. This will give you more room to work. It's worth it, trust me.
3/ Place your jackstands underneath the two rearmost rubber jack points/mounts. I went two notches high on the jack stands to give myself more room to turn the rachet/socket wrenches (a lesson learned). See pictures
4. Lower the jack and then position it under the lower control arm. Jack up the control arm to compress the spring and the shock. This will allow you to easily remove the shock's opposing nuts (inside the trunk). I believe Anthony had to put a little more elbow grease into removing the nuts because there was tension on the shock and nuts.
4. Remove both 17mm nuts, washer, gi-normous washer, and rubber bushing. You may need to pry off the rubber bushing with a screwdriver.
5. Now lower your jack to release the tension on the shock shaft. This is crucial because it takes the tension off the entire shock for safety reasons
6. Cut the existing shock boots off and then take your grinder with cutting disc and cut the exposed shaft in half. Now I've read plenty of threads here where people are trying to muscle it off, but why bother...it's an old shock you're going to replace anyways! It will just be a waste of time, unless your shocks are so worn that compressing them by hand is easy. My grinder cut the shaft in half in about 5-10 seconds
7. Remove the 10mm nuts securing the plastic cover under the control arm. Remove the 17mm bolt and nut from the lower shock mount. If it does not come off, a spray penetrant is your best bet.
8. Adding insult to injury to our hapless shock, use the threaded top half to push out the bottom half
9. Insert the bottom of the shock into the lower mount, making sure the bolt holes line up, insert the lower bolt (this is important to do FIRST!) and then loosely thread on the nut about 1/2 way. The Bilstein kit came with two washers. I put both on either side of the nut and inside of the bolt head. At the top end of the shaft, put a teeeeny amount of Petroleum jelly on the shaft of the shock. This allowed me to push on the supplied bushing quite easily.
11. Jack up your control arm again to push the shock shaft higher---this will allow you to easily thread on the hardware. Also, here's where my order of hardware differed: Anthony says "Insert the other rubber bushing on the top mount, inside the trunk. Add the washer, then the first nut (15-18 Nm). Counterholding the bottom nut, install the lock nut (30 Nm)." On my Mercedes, the order was (from top to bottom) as follows:
- Lock nut
- nut
- washer
- Gi-normous washer
- Rubber bushing
That's the order I did it because thats how it was on my old shocks. Again, put a teeeeny amount of Petroleum jelly on the shaft of the shock. This allowed me to push on the bushing quite easily. Install hardware as shown above.
11. Now here's something I did to make it a one man job: I used my 1/2" drive rachet to lever/compress the shock downwards. First, push the shock to the left. the reason for this is that the shock will naturally want to wander back in the direction of the hole. Second, put the handle end of the rachet in betweeen the shelf of the car and the top of the shock bushing. Pushing downwards, you'll catch the lip of the body. Once you compress downwards a little, flip the handle towards the shock. All the while, push the shock inwards. Once youve flipped the rachet handle, then you can easily lever/compress the shock downwards. You just want to get the shock shaft compressed and pushed into the hole. This method is 10x easier than trying to muscle it downwards.
12. After securing the hardware, lower the control arm. While you have the jack in your hands, move it under the differential, lift up the car a few strokes, and then remove the jack stands. Lower the car and let the shock settle.. I like Anthony's idea of driving it forward and backwards a few feet to settle the shocks.
13. Tighten the lower bolt to 55 Nm, and reinstall the plastic control arm cover.
The first one took me about an hour and a half. The second on easily under 30 minutes. If I did it again and had a good sized garage, I could do it easily in 20 minutes.