Hello -
I have a 1980 300TD that had the rear hydraulic suspension completely removed before I bought it. Not a trace of the original rear suspension remains. The car currently sits and drives level with new shocks all around and adjuster blocks in the rear springs. However, I am contemplating having the hydro suspension reinstalled and I'm wondering if anyone has done this, had this done and/or has opinions on this idea. The car runs great and is otherwise in decent shape with just a miniscule amount of surface rust.
Thanks for any help.

To be honest with you I would leave it alone. You don't need the SLS system. I know people on this webiste that with argure that it is a great system. From my experience nothing beats standard suspension. I have a 560 SEL with suspension problem and I have spend $$ with no results. I have 84 euro 500 SEL that have reqular shocks that ride and handle much much better. I was not wise enough to get rid of the system before I spend the money trying to fix it on the 560 SEL

Alseim,
Thank you for your reply. Did you remove the SLS on your 84 euro 500 SEL?
I'm thinking that the removal of the SLS is the cause of the considerable handling issues I'm having with my 300TD. This wagon handles very poorly. I installed brand new Bilsteins all the way around but you'd think the shocks were old and worn out. The handling is very bad; makes my Camry feel sporty. I'd like nothing better than to find a solution to this handling problem that doesn't involve spending lots of money to reinstall the SLS but I'm not sure what that solution is. If you did remove the SLS from your 84 euro 500 SEL, did you perform any other modifications to improve its handling?
Thanks again.

You would need to round up all the parts, but installation should be pretty simple. Worst part will be getting the level set properly at the controller.

However, the main reason it's missing may be an engine swap -- on most W123 engines, the hydraulic pump is on the engine, not the PS pump, and getting one with the pump is difficult (not that many wagons sold compared to sedans). If you have the pump attachment plated over, you can go ahead, but otherwise you must find a PS driven pump (it goes on the front on later models, under the pulley).

The parts, unless you happen on one in a junk yard, will be VERY expensive.....

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I think I wouldn't recommend reinstalling the self-levelling suspension. I have an 89 300te with the hydraulic self leveling system and the car doesn't handle well, even though the SLS was perfectly adjusted. I recently replaced the front struts with Bilsteins and replaced the tie rods and tires, and most importantly, I had the dealer perform an alignment. Nothing worse than taking the car to multiple tire/alignment shops and not getting the job done properly. Suspensions are complex to adjust, and anybody who claims to be able to perform a good alignment on any type of car for $99 is full of BS. A good indy with an alignment rack would have been better, but I'm not aware of any in my location. Now it handles considerably better, but still nothing like my 300E sedan. I occasionally think about removing the entire SLS, but I use my wagon to tow a small ski boat, and load it up all the time with tons of stuff, at which point it's nice to see the rearend level-up. Overall though, I think some decent coil-over shocks would be good enough and a lot less hassle. There's no such thing as just replacing the back shocks. THere's nitrogen canisters and the hydraulic cylinders, everything adding up to $$$ to replace.

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89 300te 222,222
92 300e 190,000

I would definitely NOT reinstall the Self Levelling Suspension. Leave the T as it is right now.

When I had my W123 300TD it gave me so much trouble, I finally asked the dealer to adjust the weight sensor on the rear axle as so the system will level the car ONLY if it was fully loaded.

The W124s T's I have owned did not gave as much trouble as the 123 did, but still, I did not like the system very much, especially in terms of maintenance.

My S 500 L, not being U.S. spec, thankfully has regular shocks all around.

__________________
A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]

Funny, my TE handled better than the 300D until I replace the torque and thrust links on the 300D -- have the thrust links done on the TE, still need to jack it up and do the thrust links.

Bad bushings in the rear suspension links (and bad subframe mounts!) will cause the car to handle terribly, lots of "darting about" on turns, serious instability on wet or icy pavement, etc, all due to rear wheel steering under load.

Check out the links and rear subframe mounts -- the hydraulic suspension shouldn't handle WORSE that steel spring, quite the contrary.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I have a 560 SEL that still have the SLS system. Too much money and time spent but the car still handle bad. My Euro 500 SEL did not have the SLS system ( thank god. Anyway I would not have bought it if it did have the SLS system) and it ride and drive great. Your best bit is to check the subframe mounts, check the springs and ensure that they are good. Re-installing the system is not going to make the car handle better. Also check the rubber on the top of the springs and make sure it is good. Worest case is new springs, new subframe mounts which probably cost half of the SLS pump alone.

Thanks for this tip psfred (and Alseim too). I will definitely check out the rear bushings and subframe mounts.
"lots of "darting about" on turns, serious instability on wet or icy pavement, etc"... this is exactly what is happening with my wagon. I'll have these items fixed first if there is a problem and go from there. I don't think there is a problem with the springs because the car isn't sagging... it would sag, right?
I very much appreciate the opinions and tips I've read in this forum. I wonder if my Benz is ever going to handle correctly without the originally designed rear suspension. Doesn't the SLS do more than just level the car when you load it? It is frustrating to know that people have had so much trouble with handling even with the SLS installed, however, I'm not certain that means that not having the SLS is a remedy. I guess I'll have a better idea once I have the bushings and mounts checked. I will say that the way my wagon drives right now feels like the front is fighting with the back and it isn't much fun to drive. I can't imagine that it is anywhere near how this car is supposed to drive. Makes me wish I had a sedan.

The hydraulic suspension merely gives a slightly softer ride (note that the spring rate is actually very similar, not softer) with much greater damping. Handling should be very similar if not better due to better tire contact. Roll is controlled by an identical sway bar.

Check the links for the swaybar, too -- if one is off, you will have rather shocking body roll.

I would also bounce the rear end while watching the tires and wheels -- if the rear suspesion is very stiff and movement is mostly tire deformation, you need new accumulators, the ones in there have lost their nitrogen (2000 psi or so) charge and are preventing wheel movement -- strut travel forces the oil into the accumulator where the compressed nitrogen acts as a spring. When the nitrogen is gone, the strut cannot move, and the tires bounce. This will eventually cause the tires to come off the road on bumps, quite an experience.

I'll bet you also have completely wrecked torque links. Easy to check, just set the parking brake, jack a rear wheel up, and apply torque with the lug wrench. If the wheel moves forward or backward, the links are shot. The wheels will move an inch or more if the inner torque link bushing is missing, as mine were.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I'll have the swaybar checked.
I'll also check the torque links. Was that an expensive fix?
I don't think I have accumulators. That's part of the SLS system that was completely removed by previous owner. The tires do come up off the road over bumps though. It's an experience that has made my wagon a garage queen.
Thanks again for your help. I appreciate it.

Ah, just noticed that you have a W123. Check for wheel movement as above, but if there is any, you have bad bushings in the rear control arms (different suspension). VERY squirrely indeed (the 220D has one missing, can be quite entertaining to drive!).

There are no links to worry about.

Replacement of control arm bushings is a bear, since you have to drop the rear subframe to get one bolt out to remove the control arm.

Super hard ride and lots of bouncing may be aftermarket shocks -- stick with Bilstein or Sachs, avoid KYB and anything American, they will knock your teeth lose.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I have Bilstein Comforts all around. I'll check out the bushings. Thanks!

Got some of the lack of control worked out by reinstalling the stabilizer bar that PO had removed. However...
now the rear is sagging badly and the car sways side to side. Something is going wrong with the springs that replaced the hydro suspension. Not sure what to do and I need advice. I can't afford to reinstall the hydraulic suspension, but could replace the springs. I'm wondering if that would help. I've heard the suggestion to install 126 springs on the back of a wagon that is missing the hydro suspension to get the level right.
Could new springs give the car better handling, not just get the wagon level again? I don't know why springs would wear out. I thought that they eventually just broke.
Thanks in advance for advice.