SL/R129: Convertible top problem 1990 300 SL
Thread Starter
Newbie
Joined: Feb 2012
Posts: 3
Likes: 0
1990 300SL
Convertible top problem 1990 300 SL
Hi,
After buying my 1990 300SL 129 body in 2001, I ended up changing all the cyclinders as the previous owner used the wrong fluid… yes, cost a FORTUNE!
Recently the top started to have problems only opening up ½ way through the cycle, but no further, and now when I push the button nothing happens at all. The Bosch pump is clean and looks full and I haven’t seen any leaking drops at all, so I am not sure if the cylinders are shot or if it’s the pump, or the computer [which still will open the windows], or perhaps just one or more of the cylinder sensors are misaligned.
Interestingly, even though the top is fully closed, the red light button blinks and makes a horrible beep beep noise as if one of the latches is not fully closed, [so I unplugged the computer behind the passenger’s seat and the noise stops]. Your thoughts?
Thanks in advance,
Doug
After buying my 1990 300SL 129 body in 2001, I ended up changing all the cyclinders as the previous owner used the wrong fluid… yes, cost a FORTUNE!
Recently the top started to have problems only opening up ½ way through the cycle, but no further, and now when I push the button nothing happens at all. The Bosch pump is clean and looks full and I haven’t seen any leaking drops at all, so I am not sure if the cylinders are shot or if it’s the pump, or the computer [which still will open the windows], or perhaps just one or more of the cylinder sensors are misaligned.
Interestingly, even though the top is fully closed, the red light button blinks and makes a horrible beep beep noise as if one of the latches is not fully closed, [so I unplugged the computer behind the passenger’s seat and the noise stops]. Your thoughts?
Thanks in advance,
Doug
Super Member
Joined: Jul 2010
Posts: 598
Likes: 19
From: Eastern Kansas
94 SL 600, 98 993, 89 XJS Conv., 85 Daimlier Princess 16 Hybrid Lincoln 16 Chevy crewcab
Top Hydrualics, Lighthouse is the expert I call on. Klaus has patiently taken many of use though the diagnosis. When my RST or Hardtop were not "latched" completely the warning horn and lighted switch were the signals. Where are you located?
SPONSOR
Joined: Sep 2011
Posts: 475
Likes: 41
From: On the beautiful Oregon Coast
03 SL Kleemann, 97 SL320 pano top, 95 Lorinser E320 Cabrio, Ferrari 360, Tesla X
More detail needed...
dbjacobson,
welcome to the forum! Sorry that you ended up paying a lot of money for the replacement cylinders; fortunately, it is a much cheaper and technologically better option now to upgrade your cylinders through our rebuild service. I will paste the remainder of my response in below. Hopefully, we can guide you through a DIY diagnosis on this forum.
The wrong fluid will oftentimes speed up the decay of the OEM seals in the cylinders dramatically. However, it is quite common for cars in Florida to need all of their cylinders upgraded already after some 10 years. By upgrade, I mean our rebuild service with seals that will last a lot longer than the OEM seals, and that are much more resistant to "wrong" fluids. That's why we don't limit our warranty to the kind of fluid used in your system - always read the fine print... It is important to get the wrong fluid out of your system, anyway, to protect the pump and possibly the valves. The worst enemy is water in the fluid. It makes OEM seals and similar seal material (used by other "rebuilders") swell up and crumble, and I have seen it kill a few pumps. You cannot use fluids that disperse the water in the fluid; the OEM fluid is designed to make water drop to the bottom of the reservoir.
We need more details here. Before it stopped working completely, exactly how far did the opening cycle go? Also, did it close perfectly at that time? Was any other work done around the top system before you noticed the problem? Does the controller drop both windows all the way when you try to open or close the top?
The cylinders are very likely okay. If the system has been running on the correct fluid without the pump running dry for a few years now, then your pump is likely okay. There are several possibilities with the micro switches, and the system not working at all now could be a blown fuse. Please check ALL fuses in the trunk carefully, including the big flat one on the bottom. Make sure they are not corroded where they sit in the holder, and that there are no hairline cracks in the fuses. Early models had dissimilar metal in fuse vs holder, and that lead to corrosion problems. This could also be something as simple as the micro switch in the door not having proper ground any more, so the controller doesn't know that both windows are down...
The beeping when the top is closed usually indicates that one of the latches is not closed all the way. However, we might be dealing with several issues. Did it ever beep when you were driving over a bump?
SRHsl600, thank you for your kind words. I try to help, but it certainly is not a guarantee for success when doing a remote diagnosis through a forum... Btw, "Lighthouse" is my handle on BenzWorld, where I've made some 500 technical posts so far.
One of my favorite detective stories is the following: http://www.benzworld.org/forums/r129...g-problem.html
Doug, I hope this helps, and please let us know more details,
-Klaus
klaus@tophydraulicsinc.com
welcome to the forum! Sorry that you ended up paying a lot of money for the replacement cylinders; fortunately, it is a much cheaper and technologically better option now to upgrade your cylinders through our rebuild service. I will paste the remainder of my response in below. Hopefully, we can guide you through a DIY diagnosis on this forum.
The wrong fluid will oftentimes speed up the decay of the OEM seals in the cylinders dramatically. However, it is quite common for cars in Florida to need all of their cylinders upgraded already after some 10 years. By upgrade, I mean our rebuild service with seals that will last a lot longer than the OEM seals, and that are much more resistant to "wrong" fluids. That's why we don't limit our warranty to the kind of fluid used in your system - always read the fine print... It is important to get the wrong fluid out of your system, anyway, to protect the pump and possibly the valves. The worst enemy is water in the fluid. It makes OEM seals and similar seal material (used by other "rebuilders") swell up and crumble, and I have seen it kill a few pumps. You cannot use fluids that disperse the water in the fluid; the OEM fluid is designed to make water drop to the bottom of the reservoir.
We need more details here. Before it stopped working completely, exactly how far did the opening cycle go? Also, did it close perfectly at that time? Was any other work done around the top system before you noticed the problem? Does the controller drop both windows all the way when you try to open or close the top?
so I am not sure if the cylinders are shot or if it’s the pump, or the computer [which still will open the windows], or perhaps just one or more of the cylinder sensors are misaligned.
Interestingly, even though the top is fully closed, the red light button blinks and makes a horrible beep beep noise as if one of the latches is not fully closed
Interestingly, even though the top is fully closed, the red light button blinks and makes a horrible beep beep noise as if one of the latches is not fully closed
The beeping when the top is closed usually indicates that one of the latches is not closed all the way. However, we might be dealing with several issues. Did it ever beep when you were driving over a bump?
One of my favorite detective stories is the following: http://www.benzworld.org/forums/r129...g-problem.html
Doug, I hope this helps, and please let us know more details,
-Klaus
klaus@tophydraulicsinc.com
