Hi,

I have a 1980 W123 280E sedan with SLS. The car has always sat low in the rear and only when you start the engine does it lift to semi normal height, however it is always lower than the front. It does not lose any power steering fluid.


The rear suspension is also extremely hard and bouncy, to the point when a slight bump in the road makes the car bounce up and down like a pogo stick.


Thanks

You need to replace the accumulators, the round black things near the rear shocks. That will ease the bounciness/hard ride. They run about $100 each from online parts suppliers.

It also sounds like your SLS control valve is leaking down internally. I'd change the accumulators first and see if the condition persists.

Hard and bouncy rear is bad accumulators. They are easy to replace. A couple 13mm nuts and a hydraulic fitting to remove. Be ready with a catch pan the accumulators have fluid in them so you will loose some. Make sure to get the Febi/Bilstien fluid to replace what you loose.

The saggy rear that lifts when the car starts is caused by a leak in the SLS system. The most common place is the SLS valve. The valve is in the rear near the differential. It can leak internally, or it can be leaking out of the valve. I have kits for re-sealing the valve. See the link below. The leak could be in other places so make sure you look over the system to make sure you're not leaking anywhere else. But like I said it's most commonly the valve. Also make sure the fluid reservoir is full.

Here is a link for more info on the kits-
DIY: Rebuild the self leveling suspension SLS valve on w123 300TD wagon sagging rear

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Thanks a lot, I think the control valve is leaking since the diff cover is covered with oil, but I'm not losing fluid out of the resevoir, could it be sucking it back in?

I am in Australia how would I be able to get the o-ring kit?

Thank you

The oil on the diff could be coming out of the differential or one of the axle CV boots as well -- have you checked them? And motor oil, ATF and even brake fluid can migrate aft while a car is moving.

If the SLS valve is leaking externally you should be able to see the level decline on the reservoir dipstick as it leaks. It circulates under fairly high pressure and will exit fast.

I still suggest you change the accumulators first and observe the effect before planning further surgery. I have a hydronic heating system at home. The overflow valve leaked chronically until I replaced the expansion tank (the rough equivalent of sls accumulators). New tank--no more leaks.

I also have a W123 300td that seemed to level out once I changed the accumulators. It's a subjective observation, so YMMV. My observation is that a working gaseous buffer is critical to a hydraulic system that's designed to have one.

BTW, I also replaced the old rear subframe bushings on the TD, which also can make a W123 car sag. I'd put that at No. 2 on the project list after accumulators if the bushings are looking bad.

BTW, Biodiesel 300td, if you're subscribed here, I saw the writeup you posted on another thread regarding the SLS valve rebuild. It's outstanding. I just replaced a bunch of SLS lines on my car, so I'll keep you in mind if the valve is the next thing to go.

Sorry I didn't see this sooner. I've shipped to Australia and Canada. If you give me an address I can see what shipping will be. It might add 4-5 dollars to the price. PM me if for more info

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