my boss has a 1991 sl500 n the convertible top wont go up or down. ive looked on other forums with similar problems and found out other people have had the same problem. Only differnce is the roll bar on my bosses car goes up and down. we thought the cause of the problem might be the driver side window because it also wasnt working. He just fixed it and found it wasnt the problem. If anyone has an idea of what the malfunction is please let me know. Any advise counts thankyou. Zack

 

I have a 91 500SL too. I just had some cylinders replaced by Top Hydraulics, Inc. from Florence, OR. They also replaced the tab on my arm rest and so far two of my top cylinders. Great service and very fast turn around on the rebuilt parts.
Their phone # is 541-902-3214.
They could probably give you good professional advice.