W124 strut life expectancy? Replace while I'm in there or no?
 

I know it's never going to be the same number from car to car, but i could use some thoughts on this ...
I discovered some bad rust on one of my upper spring perches, and need to repair that. I decided to do as much as I can while I have the springs out, since taking those out has been a looming fear of mine for years and I don't really want to have to relive the stress anymore than I have to.
The ball joints and LCA bushings, as well as the strut mounts and bumpers, have about 125,000 miles on them, and almost 15 years, so I decided to replace all those things. I think the springs are original and I am replacing them as well (one has a break at the bottom).
The struts themselves (for some reason not the mounts, bumpers or plastic covers), however, were replaced 50,000 miles and 6 years ago by a shop, and I'm torn on whether to replace those. They are Bilsteins. Neither leak and the ride feels great, though one has made an odd creaking sound when the wheels are off the ground the and steering wheel turned (it's the same wheel that was hit in an accident, so I've wondered if this was related). Still, haven't had any performance effects. I hate to be wasteful, since they aren't cheap, but I'd also hate to have to replace them in 10,000 miles, given that I'm not real keen on dealing with the springs again. I'm thinking I can put them back in and reasonably hope for another 40-50K ... does that sound realistic?

FWIW I have original struts on my 91 at 117k miles. I've been told for several years now that they are weeping but don't need to be replaced yet.

Put them back in and ride. The struts on a w124 car can be changed without having to mess with the springs.

I replaced mine on my 87, 3 years ago, one was seeping oil a bit, but they did seem to work fine, as no difference was noted when putting in new billsteins.
I probably could have saved the mony and ran them another 10 years.

Yep. this one.


The only way I'd change them out is if I consistently drove on poorly maintained roads, gravel roads, or headed out to the woods on forest service roads often.


...or, I wanted to get a heavier duty shock.

Run 'em!

Just me being nitpicky... if I'm correct, I think you guys are talking about dampers/shock absorbers, not struts. A strut is defined as a load-bearing component that resists longitudinal compression, whereas the shock in a W124 just damps the oscillation of the coil spring (which actually supports the car) so that the car doesn't bounce up and down repeatedly after hitting a bump.

Some cars (almost all FWD, for example) do have MacPherson struts, a combination coil spring and shock that bears the weight of the car. It looks like this:

http://www.importautoexpert.com/web_images/strut350.jpg

I always thought they were shocks before, but called them struts because the FSM refers to them as "shock absorber struts". So it's MB's fault.
Whatever the name, I will put them back in ... thanks for the advice, all. One less thing to worry about on a job that I feel like will take me forever. :eek:

Wow, you're right... and they do it over and over, too. It doesn't look like they serve a load-bearing function, though? Interesting.

...the thing to remember about these "struts" is the top mountings. Once they crack and go soft the handling goes a bit gooey - if anything replace the top mounts before the "struts" but then again age as well as miles is going to have an effect on the damping.

If you look in ye olde FSM there's actually a test with bathroom scales bricks string and paper cups to check if they are still good.

(disclaimer => not all items mentioned are necessarily necessary for this test - "comedy" is being used to encourage reading of said book!)

To be clear, they are struts because they locate the upper part of the suspension (instead of an upper control arm). They are not MacPherson struts, which are inside the coil springs, just struts. The rear suspension on the 124 does not have struts, just dampers (shocks).

I went ahead and ordered the mounts, bumpers and boots on principle ... the shop that put the shocks in 50k ago didn't replace any of that, and I figured it could use a refresh. :cool:

This! Test them, and know what you have.

Unfortunately the paper cups specified in the FSM are NLA at my dealer. Does anyone know where to source these parts? Perhaps they can be found in the special tool rental postings?

Struts.

They certainly are struts.

Shocks mount to rubber on each end... 124/201 struts mount to a bearing mount and steel... they definitely locate and function in steering...

Shocks can be removed and the car will drive.

Don't try it with a 124!