W126 Hydropnuematic suspension?
 

Hello,
My recently purchased '87 560SEC needed new gas reservoirs which I replaced. The symptoms were: lack of self leveling and a hard ride.
The self leveling problem has been solved and most of the hard ride.
My question is, there is still a harsh jolt when riding over a hole or bump. Holes and bumps that my non- hydro suspension car (380SEC) have no problem with.
I suspect more suspension or chassis component trouble. Since the ride is otherwise smooth as silk so I do not suspect the shocks. I am thinking that the rear subframe mount bushings may be worn and adding to this problem.
Any thoughts as to what I might look at?

Thanks,
Rick

I would look at the upper shock/strut mounting rubbers. Actully there is no way to look; one must replace and look at what comes out to confirm.

They are bound to be cheap 115 326 16 68 and 114 326 00 68. Ten bucks worth of rubber and a bunch of work.

Thanks Steve,
I may be wrong but I believe I can replace the rubber parts without completely removing the strut. (?)
I don't have a lift and all the work related to the hydraulic connections would turn it into a big job if I am wrong.

Rick

You need to replace the upper shock bushings. This done by removing the rear seat, opening the plastic cover, crack the hose so you can compress the shock.

This will make a world of difference. When the accumilators{ air cells} go bad the bushings get hammered, causing thumps and a hard ride. Less than hour to do both sides.

John

Thanks John,
I think I will do this job since it isn't that involved.
I did look at the rubber bushings yesterday and they look tight and in pretty good condition. The lower bushing is not that easy to see, however.
One thing that puzzles me. I replaced both reservoirs and my shop manual has nothing regarding bleeding the air out of the system.
I have designed hydraulic systems and, in pressure circuits like hydraulic pistons, etc., anytime the fluid connections are opened the air that gets in needs to be bled out.
My car is behaving like there is air in the struts.
Is this normal for these suspension systems?

Thanks again,
Rick

Rick,
The system is self-bleeding. The bushings may look ok,but when you get them out you`ll see that there mushroomed and that`s the problem.

My car is a show winner, located in Webster.

John

I have already ordered the parts.
I will do this over the weekend.
I was in Webster in early Feb. for a Little League meeting.
I know of a couple other coupe owners in Mass. Do you guys ever do get togethers?

Thanks for your help,

Rick

W126 Hydro Suspension- back to normal
 

I replaced the rubber bushings at the top of both shock/ struts over the weekend. The old ones were definitely fried. They were about 50% set of their original height.
What amazes me is the difference in ride quality that these make.

Thank you all. Now onto the ACC system.

Rick

If you only replaced the upper bushings you probably have left most of the problem. The car sets on the lower bushings not the upper ones. I refer to upper and lower, this is the upper and lower bushings of the UPPER shock mounting.

Steve,
4 bushings replaced. 2 each side.
Qty 2, part numbers 115 326 16 68 and qty 2, part numbers 114 326 00 68.

Thanks for checking,

Rick

Good job!