Beeza

Next chapter in the saga of this roof. So far I have fixed the windscreen pillar pin which makes contact with the micro switch confirming that the roof is closed and I have fixed one of the flap mechanisms which was not signalling that the flaps were out.

Next issue was a dead PSE pump which had blown its fuse that told the roof system that the boot divider was not down. I have replaced the PSE pump motor, although I do have a vacuum leak somewhere. (On the list of things to do)

I can now get the roof pump to work. In down selection, the windows go down halfway, the rear deck lifts about three inches and the top latch unlocks. The pump sounds like it's stalling. It won't go any further. Have removed the rear deck assist strut. It's quite weak, so a new one is on order. But even with a helping hand, the rear deck won't go all the way up, nor will the operation progress any further. I suspect a hydraulic pressure issue.

The question is: Is it a weak pump or do I have an internal hydraulic leak? The hydraulic lines have been disconnected. Could there be an air lock? Is there a special bleeding procedure, or does it self bleed? The reservoir is at the correct level. It did go down after a few operations and I topped it up. The level is no longer going down and no evidence of leaks from any of the cylinders.

Any tips to help diagnose?

ml320x5

With top closed, just cycle your rollbar few times or as often as needed. Should go up or down reasonable smooth.
It will tell you if it has leakage, lack of pressure...etc.
System is self bleeding. Front windows half down, rear windows all the way down....before these conditions met, trunk deck will then raise all the way back.

Frederick NL

Because in your case the pump stops, you might want to check both 118 switches on the tubular frame locks. When one sticks, shorted to ground, you land in your situation. The switches are in series, a failing cable insulation shorting current to ground tells the controller the lock(s) remain(s) closed.

ml320x5

I think 118 is working since rear deck raised about 3". Beside windows won't drop until 118 sequence is completed.

Beeza

OK. I closed and locked the roof closed. The pump continuously runs, but the roof doesn't move very much in either direction. The top latch almost fully engages, but not quite. I gave it a helping hand with the Allen key. When it was fully up, I tried the rollover bar. The pump continues to run but it won't raise. The unlocking pistons almost work. I can see the springs on the rollover bar actuator moving in, but there's not enough oomph to raise the bar.

Definitely sounds like a hydraulic pressure issue. Weak pump maybe? Electrically it sounds fine. Are there any user serviceable parts inside to check? Seals or O-rings for example? Or could there be an internal leak across the valve block or a cylinder in the system?

Edit. I did double check the valve block manual release valve. It is screwed all the way in.

ml320x5

" valve block manual release valve" Do You refer to the pressure relief valve at the hyd. pump unit area where you manually turn it to relief pressure?
Sounds like low pressure problem.
My guess is that relief screw. Take it out and have a look. There is a O-ring at the end. Check the condition. You may also been tighten the screw too hard and crushed the screw end where it does the sealing. Good Luck.

aegea

Please let us know if you solve the problem. I have invested about $3-4k in the Vario roof. The roof worked perfectly after I replaced the front latch cylinder with a Top Hydraulics rebuild. I have had subsequent leaks, working periods, replaced all cylinders, had Top Hydraulics to rebuild the pump, replaced front latch assemblies, etc. After the roof last worked for a few cycles, after pump rebuild, the trunk became stuck pointing up with flaps deployed on the opening cycle.

peterkay

If there is a leak - your pump will be low on hydraulic fluid. There isn't much of it in the system and it drops very quickly even if you have a small leak. Just check the level in the plastic container.

When you say a support strut, is it the one on the passenger side assisting the cylinder? Do you have a part number for it?

jonseal

Meaning that the seals in some cylinder are bad, but the o ring may be good so the fluid goes around the seals and out the other supply line. thus not lowering the fluid level or leaking on the carpet. I am in the process of trying to find the culprit in my 2005 SL500. In the process I was going to change the seals in the lift assist cylinders on both sides but I can't figure out ow to take them apart. So I would appreciate any help anyone can give me with that and I will report my results here. I am going to try to add a picture here of the assist cylinder.

If anyone knows how to take this apart please let me know. Thanks, John Seal

peterkay

I went through this. My car is twenty years old. The weakest seal leaks. I send it for rebuild to FL. I put it back, the system is pressurized. I wait for the next seal to leak. You cannot rebuild these at home. The endlink is pressure fitted. Takes special setup to take it off.