I think the reason with MB springs is two fold...

One, the springs are small diameter springs, and as such, they need to compress a LOT to hold the car... Also, the coils are very close together, not much room for external teeth to grab.

Two, the springs sit inside a deep pocket up top, so the coils nearly have to touch to clear the pocket.

On most American cars with coil springs, the lower control arm can lower enough to clear the spring without compressing at all, unless it's a McPherson Strut, and they don't have much pressure on them, because the strut has a lot of pressure... So the coil is very weak.

Mb has the spring deal with the entire weight of the vehicle, and the travel rate fully loaded.

It helps to mark the shaft where the nubs are to help with aligning in the bottom plate. I marked mine after realizing that I wasn't locked into the bottom plate. Fortunately there wasn't a great load either.

Also greasing the shaft helps the tightening process very much. It doesn't take a lot of grease but I grease for every job which has been defined as 2 springs each on 2 SDs.

"Toolmarks"....
 

We might not want to overlook the possibility of improper tools causing a mark on the spring.
I once worked at a manufacturer who had to make certain that there were no toolmarks in the structure that could lead to possible future structural damage by being a location where stress in the structure could lead to fatigue cracking. In our case, this could be a spring failure at a later date, and is a possible cause of some reported W123 "random" spring breaks, where a car sitting unused has the spring suddenly break for no apparent reason.
The correct way to work with the spring is only to compress with the proper tool. There are no instructions for heavy prying, hammering, or pounding on the spring. There are no substitutions for the correct tool because of the method that is used to compress the spring, which will cause no "toolmarks".
A "grocery store" variety spring compressor cannot be used as it is not designed to do the W123, as the W123 is above and beyond the safe intended use of the tool.
I will be ordering a Klann-type spring compressor so get what little "peace of mind" I can get in just about a week. It will be stressful enough torquing that spring down. For the extra "expense", I can buy peace of mind for a few dollars, so I can return and post my survival story, without a body cast or bandaids. Priceless.:)

The right tool is worth it!

snapped_bolt

I have to admit that the first four springs (two cars) I did, were done with the outer style spring compressors. I was able to do them successfully, but not without saying many prayers. I have since purchased an inside compressor, and feel much better about it the times I have used it. Even with the proper compressor, removing the loaded spring and compressor feels like I am carrying a live land mine or sweaty dynamite . I take it out with a big pair of pliers, and set it down easy and pointed away from me.....Rich

I had to do this job on my E300. It is straightforward and relatively safe with the proper Klann tool and reasonable caution. I would never try to improvise on this job as there is just too much stored energy.

It's perfectly fine to grasp the compressed spring in the center of the coils so long as you are using the proper tool, the tool has not been abused, and the tabs are properly locked on the disks.

Just be sure to never point the rod towards yourself or others.

Always set the spring down gently (never drop or throw it) with the rod pointing in a safe direction away from the work area.

When initially loading up the tool, stop cranking when the tension starts picking up. Inspect both top and bottom, with a mirror and flashlight if necessary, to ensure the tabs are locked correctly in the disks before proceeding.

If the spring compressor lets go all the energy will go out along the axis. Treat it like a loaded gun.

Great info Jay Bob. :thumbsup:


Charlie

See post #15. On a W123 there is plenty of space to use generic spring compressors but you can see the bending.

In the thumbnail pic is one I made from 1 inch threaded rod that worked OK with the exception that the hook that slides tends to flatten the threads on one side. It is likely ACME threads would be a better choice as the ACME threads do not come to a point but are flat on the outer surface.

I made the big hooked Spring Compressor so I could use it on non-Mercedes vehicles.

ACME, that's what coyote buys to use against roadrunner.

Thank you all for the responses! It's all very helpful and interesting... and gives me more respect for the car and the tool.

Sorry in post 22 I was supposed to have posted a link showing the generic spring compressor bending. Now I don't know where the link is.

And he always looses. :D



Charlie

you may still want a standard exterior spring clamp around when you do the job as it can be helpful to straighten the spring out a bit for removal for the front.
this thread has a pic of what im talking about on the last page

http://www.peachparts.com/shopforum/diesel-discussion/291932-front-coil-spring-snapped-1983-240d.html