Hi,

Well the car is just about where I need her to be... and I have only one thing left that I HATE about the car...

The rear end... here's the story:

If the car is parked overnight, the rear end drops down -- this is noticed because when I start the car, the car jumps back up (I can actually see the rear of the car 'pump' up)...

Now... the problem is that when I go over pumps the rear end bounces up and down like a crazy bastard to the point where I can't stand it!!! --- so, I just want to know what I should be looking at.

I'm thinking 2 struts and 2 of those "black pods" that I see under there... but let me know what I should be thinking...

Thanks again,

Pete

There are lots of posts about the 300TD rear suspension. Check the archives for "self levelling suspension." Hopefully yours might just be leaking. To replace all the junk back there, as I understand it, is very expensive.

Good luck!

Chris

Sounds like the struts aren't doing any damping. Before changing anything out, check and make sure you have the proper amount of fluid in the SLS reservoir when the car is at the proper ride height.

FWIW, back in the fall, the struts on Thing One's wagon were leaking like sieves. I couldn't justify replacing the fluid with that $9.00/liter liquid gold that MBZ sells so I went to an ag supply house a bought a gallon of high-end (name brand) tractor fluid.

I fixed a leak at the reservoir, topped the system off and sent him on his way. 2000+ miles later, I'm in New York driving the car and realize that, not only did the struts stop leaking, but they worked pretty darned well too (we had seven people in the car at two different times!).

__________________
Never a dull moment at Berry Hill Farm.

R Leo -- you just answered a question I was JUST preparing to post! Ah, serendipity! What oil did you buy to use in the resevoir? I don't have access to the MB stuff locally, nor do I want to shell out the $$$ for the fancy stuff just in case my "fix" didn't really fix my leak. Tried that once and out it all went onto the ground...

Thanks!

Chris

Pete:
The sagging when the car has been sitting is usually a tired actuator valve in the rear. MBZ sells rebuild kits and I've been told it's not too hard a job though I've never done it myself. The hard ride/bouncing is usually the black spheres. They are supposed to be half fluid/half nitrogen separated with a rubber bladder. Over time the bladder lets go and the sphere fills full with fluid and you loose the cushioning. Neither of those jobs is terribly expensive. The struts are usually the last thing that fails but also far and away the most expensive to replace. If they aren't leaking then worry about those last. There are lots of threads here that will give you good step by step details on all these repairs.
LRG

__________________
LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

It was a dirty job, but it makes a huge difference! No more bouncing!

If you complete a search on the forum, you will find lots of information.

Good luck!

Ahhhhhhhhhh! I have no leaks in the system... so that sounds like it is a good thing!!!

Is there a way to test the spheres? Or is this just such a VERY obvious thing that I should just change them and that's that?

Search for "accumulator" and get ready to read for a while. I don't remember seeing a test, but there may be one. Everyone says if the ride is bouncy, change them. Probably been said here 20 times or more.

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

I'm not aware of any test other than the "gee my car sure is riding hard in the back" test. I could tell mine were bad when I jumped up and down on the back with the engine running and got little or no bouncing. If in doubt replace them since if they are old and not bad now they probably will be soon. By the way, I strongly recommend you use a flare wrench on the brass hose fittings because they are easy to strip. Also wear an old shirt because you'll be throwing it out afterwards.

__________________
LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

I did the search -- the problem is I'm getting two different stories...

First I'm hearing if the spheres are bad the car DOES NOT bounce, and then I hear if the spheres are bad the car DOES bounc (like crazy) ------- SO which is it?

My car bounces like MAD -- BUT I just got back from inspection, and it didn't fail!

Explain that one!

Pete

Passed inspection = inspectors who have no idea how a MB hydro suspension works. Imagine that. Luckily, here in the sticks of IL, we don't have inspections of ANY sort! Good thing, considering the amount of rot on some of the cars I've owned, and I can't remember the last time I had a crack/chip-free windshield.

Good luck getting it all sorted out. Not sure about bounce vs. no bounce... I'm sure someone will reply!

In my case it was no bounce and very limited dampening. Take a speed bump at a slow speed and it was a hard thump. At faster speeds I could get oscillations going as the fluid system tried to regulate the ride height with no dampening. This made it feel a lot like it had bad shocks. It did not bounce like a ride at Disneyland however. The system is pretty simple as there are really only 4 parts of any consequence.
1. pump
2. actuator valve
3. spheres
4. shocks

Your pump is obviously working. The actuator is working too except that it is bleeding off the pressure when it sits. A rebuild should fix that. The spheres are probably bad if the ride quality is hard (as opposed to firm). If the hyd. shocks leak or allow the car to bounce uncontrollably (as opposed to the actuator valve pumping up and down) they may be bad. My understanding is that the shocks seldom fail except to leak around the seals. If it were me I'd rebuild the actuator, replace the spheres and then see how it is before going further.

One last thought. It might be possible that somehow you have gotten some air in the system such that there is no fluid in the shocks and therefore NO dampening. The system is supposed to be self bleeding but just for grins you might want to crack open the bleed nipple on the actuator (with the engine running and the car VERY well secured on ramps at the rear) and bleed off some fluid to see if it makes any difference. It should flow out by itself fairly gradually, at idle the pump doen't produce a lot of pressure. If the fluid has never been changed in close to 200K miles it may be so gummy that the system just isn't working right. Good luck!

One more last thought, obviously you should also check that the drop links, torsion rod, etc. connected to the actuator are in all connected properly and in good shape.

__________________
LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

My ride is very bouncy. If I push down on the rear buper it wils bounce like it's riding only on springs, much like having dead shocks. I have been told a few times just to replace the spheres.

The only way I can think to test them is to remove them, fill it up with fluid, pour it out and compare how much it holds with the oerall displacement of the sphere. I don't know what % of the sphere is the nitrogen bladder, but I'm sure it's quite big.

If you can have the car offline for a few days, go ahead and pull the spheres. Once laying on the floor, if the spheres are good, you won't be able to get any fluid into them. The bladder (and the nitrogen behind it) will push all the way to the port on the sphere. If they are bad, they will be full of fluid and when you remove them, you will be able to dump out 250-500ml of oil (a lot, makes a mess on floor). Real go/no go sort of thing. They are not too hard to remove, just takes a few wrenches (flare fitting wrenches are best for connections) and a socket on long extension to take the mounting bolts loose. Just remember to bleed off the residule presure from the system first. There is a bleeder screw on the actuator. (hint: if the the car is supported on jack stands and when you open the bleeder screw, only a little fluid comes out, spheres may well be bad). One more thing. If you have to take the actuator rod loose, be sure to mark which hole it came out of. (You will understand when you get there.)

Hi all.

I agree with "lrg".

But one other thing that hasn't been metioned
before is,that there is a filter in the reservoir.

Pete, If you don't know the extend of the maintenance
on the self leveling system,then replacing the fluid and
filter is recommended.
If memory serves the system takes 3.5 liters of fluid.



Louis.