300 TD suspension question

[Francois007]

Hey guys hoping to find some help/advice. Recently got a 300td passed down to me and took it for service to get an inspection and was told there is a heavy oil leak from the suspension pump. I know these cars run the SLS system do I have to repair the whole SLS system or is there any way to delete the SLS as a whole and run normal shocks that I can just bolt in ?

[shadetreemechan]

Rebuilding the pump is cheap and easy. Deleting the SLS is a lot of work, expensive, and ruins the value of the car.
It is most likely not the pump itself leaking, but the high pressure line coming out of it. There are lots of threads on here on how to do that.

[sgnimj96]

There are enough discussions about putting in normal rear springs, you can find them. I don't know if it's really hard to do, but the rear springs are a lot easier to remove than the front ones. Unfortunately, the SLS system's simple replacement parts aren't as easy to find these days so I don't think going mechanical suspension will lower the value unless your trying to keep it a vintage classic. I got my wagon cheap because it had a leaking rear shock (hydraulic ram), if I had known how much work it was going to be for me to fix, I would have wanted to pay less.
The pump is probably the easiest to replace seals on, after you find them. After that, change the filter in the reservoir and flush it good. If you're lucky nothing will start leaking when it pressures up. The control valve in the back just needs a few o-rings to rebuild it. There was a member that sold a kit many years ago that I fixed mine with, but he's long gone. If the hydraulic shocks leak, it's rumored to be simple, specific repair, but hardly anyone knows how to do it. I was lucky enough to have junkyard ones when mine started leaking - new ones are like $1000 bucks each, so there's that. Even the SLS fluid is expensive, I bought 5 gallons of shell tellus t-22 to flush and run. Works good.

If the fluid in that system is clean (and correct), it's relatively trouble free. The fluid in the reservoir of my 300td was black, and ruined everything EXCEPT the hydraulic pump. So fix that leak then figure out where you're at and how you want to proceed. Also, the gas pods in the rear have to be replaced after so many years because the nitrogen gas leaks out. There are lots of good reasons why people get rid of the SLS and why people keep it.
Here's a (rare) w123 pro giving his opinion.
https://www.youtube.com/watch?v=GT2HgZ62ZYo
I know, for me, it was really helpful when I used my wagon to put pavers down at the back of my house (a lot of them). Loading cheap bricks from home depot and got fill dirt from a local quarry. The only alternative to that is to have a truck,
but shovelling stuff into the back of a wagon is as easy as it gets, nice and low, just put a tarp down. I'm pretty sure
it will hold 1000lbs no problem.

Unfortunately, my wagon has taken a beating in the florida rains and has been rigged and rust patched a lot so it's never
going to be worth a lot, just runs good. So if you have a nice looking wagon, it's probably worth saving the SLS.
If you aren't planning on being your own mechanic, that's a different world.

[Sugar Bear]

Try to thoroughly clean and examine the system for the exact location of the leak. Depending on what is wrong with the SLS it may cost less to fix it vs. a conversion. If the car is a clean keeper do your best to fix the SLS it is really nice when working properly. No matter what you find plan on replacing the nitrogen spheres, they are the shock absorber of the system. The hydraulic struts that look like shocks are not the shock absorber rather the device that does the lift/lower when pressure is added/lowered to them.

[jsb357]

Originally Posted by Sugar Bear

The hydraulic struts that look like shocks are not the shock absorber rather the device that does the lift/lower when pressure is added/lowered to them.

The struts can develop leaks, are NLA and expensive to rebuild...

[Francois007]

Thank you so much for the replies going to keep SLS system after all the advice. Any tips on removing the high pressure line without making a mess. Also when removing the pump from the engine do I need to drain the oil first.