I did a search with no results for what I'm looking for. I finished putting new accumulators into the rear of my 95 S600. Bled the system and changed fluid. I am disappointed that the ride is not as soft as I had anticipated. It seems less bouncy than before, but I'm not certain yet. I have to drive it more. I would have thought that if I had bad accumulators (which I'm pretty sure I did), the ride would be much smoother with new accumulators.
I'm looking at other components now to see if there are any additional problems. Can anyone explain the function of the damper valve assemblies in this system? They are in line between the axle height valve and the struts. I assume these are the valves that firm up the ride when firm mode is selected. Do these valves restrict the flow of hydraulic oil to provide a firmer ride? How are these valves tested to evalute if they are functioning properly?
I wonder if I'm being to critical of the ride quality. Is there anyone in the Chicago area with a W140 willing to drive me around in their car so I can compare ride quality?
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1995 S600, 1 of 618 (sold)
"Speed is just a question of money...how fast you wanna go?"
Hi Pete,
As you know oil cant be compressed, but air/gas can. The pump pressurises the system, the hydraulic fluid is in both the shock and bottom of the accumulators ince they are "td" together at the bottom. It is constantly circulated or bypassed in the leveling valve untill the arm moves the lever and oil is routed to to the hydraulic/accumulators. The rear end rises the sway bar twists and shuts off the flow (bypass). The ADS system has valve(s) in line, and restricts (firm,normal,soft) the fluid flow from the pump to the accumulator/hydraulic shocks, and gets its signal from the computer,and also provides a similar function on the front shocks by controlling the fluid flow within the shock. This system has many sensors, steering angle, lateral/wheel acceleration, and body load (which is in line with the left rear) accumulator. The default is "firm", but depending on tire pressure it could be working. MB halways had a tight ride for those autobahn spurts! I hope this helps!
I dont know how to test components,it is probably beyond the scope or equipment for us normal folks.
Can't help with how the damper valves work. I've had the same
impression with the ride, though. The ride is not as smooth as I had expected for a 5000 lb car. I still seem to feel lot of the bumps in the road. A lot of jolt seems to get transferred to the frame rather than absorbed in the springs. My great aunt's Lincoln Town Car certainly has a more cushioned ride.
I have chalked it up to the suspension being tuned stiffer for high speed touring on European motorways as Peter alluded to.
My ADS light comes on intermittently right now so my suspension might not be working completely correctly. I haven't been able to tell a difference, for example, when I have the button in firm or soft mode.
Vehicle: SEC 600 COUPE (RHD) One of the chosen few.
Location: Leicester UK
Posts: 1,358
RE: Who understands complete rear suspension?
Congrats on your work.. However It will take a little time for the sysem to settle down - I think in 500 miles or so you will notice the difference.. try riding on firm for a day .. will help the spheres balance themseves up and get a good stretch ..Did you do a complete change of oil- hydralic fluid ?
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Thanks for the congrats Merc600sec. It was a little easier getting the new parts in, than getting the old parts out. The small high pressure line going to the struts is a nerve-wracking line to re-attach. You can't start these more that 1/4 turn with your fingers. I was deathly afraid of cross-threading them as you can't see if the fitting is lined up properly with respect to the accumulator mating thread. I had to use a wrench to start them. I pulled them both out after a few turns just to make sure they were going in straight, and they were. It's unusually tight for this type of fitting. I wasn't aware that these things had to "settle" in. Is this for real? I'll set it on firm for a day. I will note the mileage, and see if I can feel a difference in 500 or so miles. I swapped out 2 liters of very brown fluid by running the engine with the return line draining into a bucket. I do not think it's possible to purge all of the old oil from the system, even when raising and lowering the car several times by moving the axle height valve arm. In any case, the fluid is clear now. One thing I noticed when testing the axle height valve...before I changed the accumulators, the car rose much more quickly when so commanded with the axle height valve. With the new accumulators, it raises much slower. Any thoughts on this?
The faster response to the control valve is due to the lack of compressed gas in the spheres. With the diaghrams ruptured they are totally full of oil and any new pressurised oil introduced into the system will imediately cause vertical motion. With new spheres the rear will rise slower as there is a gas cushion which will cause a damping effect as the pressure on the gas side increases to match the fluid side pressure. Before all of the new fluid went to the strut while now much of it is stored in the spheres till pressure ballances.
Linear Mode
