SL/R230: How to bleed or prime vario roof hydraulic pump?
Just a suggestion, You may want to make it with serrated internal side wall as it will gives a better grip. I would still use potting compound or JB weld since the pin is under tension load most of the time. Would like to see how it turn out. Good luck.
**EDIT**
Here's the file if anyone needs to print the dowel: https://www.thingiverse.com/thing:5142412
Last edited by cougar694u; Nov 20, 2021 at 11:57 PM. Reason: Added link
Nylon filament is in the dryer (it draws in ambient moisture when sitting, causing print inconsistencies), and will print a horizontal version, like a torpedo.
Nylon filament is in the dryer (it draws in ambient moisture when sitting, causing print inconsistencies), and will print a horizontal version, like a torpedo.
Last edited by ml320x5; Feb 8, 2021 at 11:24 AM.


Nylon filament is in the dryer (it draws in ambient moisture when sitting, causing print inconsistencies), and will print a horizontal version, like a torpedo.
The polar vortex also played with me. It was 7 degrees F here in north east San Antonio and didn't get above freezing for about 5 days, I had no electricity, no water, no cell service, it was fantastic! LOL! I did have a generator running my furnace, which is gas, and had plenty of food & water on-hand, so I actually enjoyed it. Then a week later it was 80 degrees F, go figure.
Anyway, I think that temperature swing had some impact on the car, as it wouldn't start. Turns out the fuel pump fuse became corroded during those two week. Cleaned off the spade terminals on the fuse, reseated it a couple times, fired right up, top works like a champ.
The Best of Mercedes & AMG
Bought a 2008 SL350 about 6 months ago, and has enjoyed driving it, especially with the roof down. However, problems soon arise.
I have a question that I think is related to the priming of the hydraulic pump as well, hence me posting here.
Situation is like this:
Initially I found that there was a leak in the roof hydraulic system. Oil in the reservoir keeps becoming empty, but we cant detect any leaks.
Roof can open and close without any issue when there's oil in the reservoir, but averaging after about 4 to 5 cycles of opening and closing, it will become empty again.
Numerous visits to my regular workshop also resulted in frequent topping up of hydraulic fluid, but still no sign of where the leaks are.
All 11 cylinders were physically checked and the leak wasn't there.
Finally after own monitoring, I found that the leak was within the pump block itself. Between the solenoids and the pump valve block.
I removed the pump, dismantled the components and found that the 3 O-Rings between the valve block were flat. It was also likely the previous owner had put silicon around it, and with the silicon failing, resulting in the leak.
I cleaned up the pump, replaced all 3 o-rings and pieced everything together. Plugged all the hoses back, refilled the reservoir, reconnected all the plugs and wiring, and tried to open the roof.
Good news? No more leak.
Bad news? Roof doesn't open. Like, at all.
When I pull the switch to open the roof, I can hear the hydraulic pump running, and the trunk pops open slightly, but that's it. No movement. I've attached a picture of the trunk stopped in half open state.
I usually just leave repairs etc to my regular workshop to sort out, but this time, they said their supplier for parts are facing a shortage, not to mention a rarely replaced part like the roof hydraulic pump.
That's why I decided to try doing it myself.
Have consulted the R230 bible at https://julianehehl.de/sl55amg-dach5-1.htm, as well as checked and read numerous forums, but I'm at my wits end.
Some has suggested that after dismantling and reassembling the hydraulic pump block, we need to prime it or it will not function due to air lock. Pump is running, but no hydraulic fluid is being pumped to the valve block due to air in the system. Could this be the case?
As this is the first time I'm going hands-on to do my own repairs, I appreciate any and all advice or suggestions that I can try to hopefully resolve the issue.
Details:
Model: R230 SL350
YOM: 2008
Hydraulic Pump Part Number: A230 800 00 88


I have no other input, as my pump is different than yours.
Not sure on the O-ring sizes. I brought the whole pump unit to the seal company and just let them fit them with replacement o-rings.
I have no other input, as my pump is different than yours.
Most funny thing is, my normal trunk opening runs on the hydraulic pump as well, as i have 2 extra hydraulic hoses attached to the pump. That section works fine. Just not the roof.
I'm literally pulling my hair out, trying to solve this.


Have you tried manually pulling on the trunk lid to get it to open while the pump is running?
Also dumb question, have you checked that all the lines are in the correct spot on the valve block?
Actually, I wonder if it's switch S118/1 or S118/2 not signaling the trunk is actually unlocked and ready to flip up, essentially failing during Stage 1 and not continuing. I had a similar issue where it couldn't tell the driver's window position, so it stopped with the trunk flipped up. The motor ran, everything appear normal, but just stopped.
Stage 1 of the roof opening sequence: Next (y5) energizes, causing cylinder 3 to unlock the front Vario roof locks. Switches S69/2 & /3 confirm it’s not locked. Next, cylinders 4 & 5 unlock the tubular frame. Switches S118/1 & S118/2 confirm it’s not locked. Front windows move to short stroke position, rear windows open completely. Cylinder 8 causes trunk lid to move to the raised position. Switch S119 confirms trunk lid is raised.
Do the windows move down that 1/2 inch or so?
Roll Bar when pressed works very slowly.
No Roof. I can see the hydraulic locks unlock when I activate the roof opening switch.
Bypass is closed. I made the mistake of trying to open the roof with the bypass open once. Massive cleanup of hydraulic oil all over the trunk area. (Just FYI for those who are thinking of trying with the bypass open)
Have you tried manually pulling on the trunk lid to get it to open while the pump is running?
Also dumb question, have you checked that all the lines are in the correct spot on the valve block?
Actually, I wonder if it's switch S118/1 or S118/2 not signaling the trunk is actually unlocked and ready to flip up, essentially failing during Stage 1 and not continuing. I had a similar issue where it couldn't tell the driver's window position, so it stopped with the trunk flipped up. The motor ran, everything appear normal, but just stopped.
Stage 1 of the roof opening sequence: Next (y5) energizes, causing cylinder 3 to unlock the front Vario roof locks. Switches S69/2 & /3 confirm it’s not locked. Next, cylinders 4 & 5 unlock the tubular frame. Switches S118/1 & S118/2 confirm it’s not locked. Front windows move to short stroke position, rear windows open completely. Cylinder 8 causes trunk lid to move to the raised position. Switch S119 confirms trunk lid is raised.
Do the windows move down that 1/2 inch or so?
Yep, Tried manually pulling the trunk open while pump is running. Doesnt work. Cant pull anything at all.
Yep, checked all lines are in the correct spot on the valve. Took out all the inner trunk lining just to trace every single line to its cylinder.
Yes, stuck at Stage 1, and doesnt proceed at all.
I suspect its somewhere along the lines of the switch as well, but not sure on how to verify it.
Yes, the windows move down that 1/2 inch upon activation of the roof switch. I even tried activating the switch with all windows down. No go.














