300 SD front shock change question
 

Purchased two new front shocks for my 83 300SD. Got the front all jacked up and noticed the 12 sided bolts securing the lower shock body. Trips to NAPA stores -across town of course-netted the proper metric socket.

However, I can only remove the 'outside' bolt. The shock body is in the way of the inside bolt. After removing the upper nuts, I lowered the jack, hoping to free the top end of the shock. No luck.

I thought of torching the shock body in half, but was afraid that replacement would be stymied.

What is the proper manner to change out SD front shocks?

BTW, control arm bushings are shot. Is replacement a big deal?
Thanks.

You are trying to remove a permanent bracket - put the bolt back in and leave it alone. Take out the single horizontal bolt at the bottom of the shock.

The top of the shock is secured by a double nut or 2 nuts jammed together. If you took out both of them the shock should have pulled out when you lowered the wheel.

Not to be smart but if you are having difficulty removing the shocks you should take the control arm bushing job to a mechanic.

Be very careful, the shock is all that holds the front suspension up. If you let it go down too far the spring could go flying. It packs a mean wallop. I have seen good mechanics lose teeth for less.

Don't try to remove the shock by lowering the wheel beyond it's normal travel. Support the wheel securely at the bottom of its travel. Take out the bolt, remove the nuts and push the shock down or drive it down with a hammer and punch.

You probably won't be able to get a socket on the inside bolt, but a 12 point box end wrench should work. You might have to jack up the lower control arm (or put the wheels back on the pavement) to change the angle of the shock so you can get access to the bolt.
The lower control arm bushings are a big deal primarily because you need a Mercedes specific spring compressor to do the job safely.

I've done the exact same job recently and had the exact same difficulties.

You can get a 12 point box wrench in there, but just barely. It took me over 1/2 hour to get that damn screw out and another 1/2 hour to get the new screw back in.

A better solution, which I have subsequently found out, is to force the piston down below the body and fender and rotate the shock outward away from the vehicle. Now the screw is out from under the shock and readily accessible.

shock
 

it seems i have done this... i think that if you undo the top first and tilt the shock out the back 12 piont bolt is accessable with an extension.

double the warning on the spring if it flys out i would think you can lose more than the teeth.

On the SDL, there is a welded bracket which will stop the downward travel of the upper control arm. This bracket has just a slight bit of clearance when the spindle and bearing assembly is hanging on the shock. I supported the lower arm when I removed the shock, but, in the case of the SDL, I'm fairly certain that it is failsafe. The spring could not escape with the shock removed and the lower arm unsupported.

I haven't checked the SD for the same bracket.

Thats what I did along with kind of turning the shock a bit once the first bolt is out of its base. Then I used a 12 point wrench but a socket would just fit once I got the bolt started with the wrench I finished with a socket.

My 10mm 3/8 drive Craftsman socket seemed to be 12 points and grab the bolts.


Like all suspension work it is a royal pita, I hate suspension work.

No, the spring will not come flying out on your '83 SD, don't worry. There are welded stops in place that prevent the suspension from ever dropping far enough to release the spring. The shock does hold the suspension off the stops, but only about 1.5 inches. If you forget to take the top nut off the shock first, it will just go "pop" and drop onto the stops. I used a small box end wrench for the hard to get bolt on the bottom, but I did have to grind it pretty thin to fit. PM me with any questions, I just did this job..

Thanks to one and all.
 

Thanks for the responses. Will try again this PM.
Will try the 'push the shock rod down' and 'rotate
the shock base methods. And try to retain all my
fingers and toes.
Jones

300 SD Shock change success
 

:D
Many thanks for all the helpful tips. I used a variety of the suggestions offered and completed this job as follows;

Secure a 10mm socket -12 points;
Loosen front lug nuts-one side only;
Jack up front of car; Secure with jack stands; I also used a jack under the wheel suspension assembly to prevent spring flight. There was some debate about this and I didn't want to take a chance;
Remove wheel;
Tap 12 point socket onto the shock mounting bolt you can reach (outside bolt)-remove bolt;
Remove double nuts from top of shock; remove bushing and washer from shock top post;
Using a socket and extension, shove down the shock post into the wheel well while pulling shock away from engine with other hand. This sounds harder than it is;
Remove other shock mounting bolt which is now easily accessible-pull old shock free;
Install new bushing and retaining washer onto top of new shock per manufacturer's instructions. I used the manufacturer's tiedown to hold the shock in compact position for installation;
Reinstall shock mount bolts with blue threadlocker and torque down;
Align shock post to upper mounting hole and cut tiedown free. Shock will slowly extend itself into position;
Install new bushing and washer to align shock properly in upper mounting hole;
Install new doublenuts with blue threadlocker and torque down;
Reinstall wheel; Tighten lugs; remove/move jacks;
Repeat on other side.
Took about one hour to change both shocks.

Thanks again for the help.
Jones ;)