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Registered 2005 SLK350
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113 Posts
This is a new problem.

It seems/acts like/appears that the pump is developing inadequate pressure to properly raise and lower the top on its own. If someone operates the switch and I provide a lift assist to the roof, etc it works fine. It just seems like the pump's pressure isn't adequate to operate it by itself. It just started this all at once, not a progressive thing.

Any thoughts or pertinent experiences with anything like this?
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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97,410 Posts
How old is car battery?
This has been shown in the past with roof issues
Is car on when testing roof?
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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97,410 Posts

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Registered 2005 SLK350
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113 Posts
Discussion Starter #4
How old is car battery?
This has been shown in the past with roof issues
Is car on when testing roof?
it's not the battery. It cranks the car fine. The top runs the same with the car off/ign or running, it makes no difference. Everything sure points to the hydraulic circuit (pump most likely, possibly a partially stuck solenoid). I'm sure there's a way to check the output pressure of the pump. I've searched high and low and can't find any troubleshooting that really homes in on the hydraulic circuit, save the cylinders.
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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97,410 Posts
Believe it or not, the battery comes into play for the roof operation
We have had members playing with the roof and the top would slow down because of drain on battery. just sayin'
 

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Registered 2005 SLK350
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113 Posts
Discussion Starter #6
Battery is 12.8 VDC static, 14.3 VDC engine running. I can rule out the battery. I guess it's possible that I'm not getting full battery voltage to the pump. Then again, where do I check pump voltage at?
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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97,410 Posts

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Premium Member 2005 SLK55 AMG; 2005 SLK350
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5,065 Posts
Definitely test the battery.

The pump could've failed, or a solenoid failed, or a seal failed, or some other blockage found its way into the lines (which would likely be one of the aforementioned seals).

It takes some pretty specialized equipment to test the ten different circuits. It would be good to have, but I haven't seen anybody here do it. I sent mine to top hydraulics, they did it right.
 

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559 Posts
As efair said, I'd start with a batt test. The voltage readings are fine but it might change when you put a load on it. Secondly, are you sure you have enough fluid in the system? After that, you could take a shot at flushing and filling the system with new hydrallic fluid. Here's a good post on it (though sadly it degenrates later on). http://www.slkworld.com/slk-r170-class-diy/25664-roof-hydraulic-pump-draining.html If that fails to do anything, it might be time for a cylinder rebuild. I've never used him, but this is reported to be 'the guy' for cylinder rebuilds. https://www.tophydraulicsinc.com/en/20-r170-slk

Finally, anyway you'd loan your 427 ac cobra for a day or two? (Asking for a friend).
 

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Registered 2005 SLK350
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113 Posts
Discussion Starter #11
Definitely test the battery.

The pump could've failed, or a solenoid failed, or a seal failed, or some other blockage found its way into the lines (which would likely be one of the aforementioned seals).

It takes some pretty specialized equipment to test the ten different circuits. It would be good to have, but I haven't seen anybody here do it. I sent mine to top hydraulics, they did it right.
It sure looks like I need to find someone specialized in my area, Port Charlotte, FL. There's just too many possibilities. FWIW, all circuits/cylinders are seemingly operating at a reduced pressure. As long as I assist with a gentle lift or push it runs through the cycles fine. My gut feeling is the pump. There's several used ones on EBay.
 

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Registered 2005 SLK350
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113 Posts
Discussion Starter #12
As efair said, I'd start with a batt test. The voltage readings are fine but it might change when you put a load on it. Secondly, are you sure you have enough fluid in the system? After that, you could take a shot at flushing and filling the system with new hydrallic fluid. Here's a good post on it (though sadly it degenrates later on). http://www.slkworld.com/slk-r170-class-diy/25664-roof-hydraulic-pump-draining.html If that fails to do anything, it might be time for a cylinder rebuild. I've never used him, but this is reported to be 'the guy' for cylinder rebuilds. https://www.tophydraulicsinc.com/en/20-r170-slk

Finally, anyway you'd loan your 427 ac cobra for a day or two? (Asking for a friend).
The battery and fluid is fine. Last year I rebuilt the front cylinder and it's been operating flawlessly, until now. The hydraulic fluid, by large, is clear and fresh, The only thing I'm sure on is that it's not a cylinder problem.

We could probably work something out with the Cobra for someone who fixes this darn top... lol.
 

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The battery and fluid is fine. Last year I rebuilt the front cylinder and it's been operating flawlessly, until now. The hydraulic fluid, by large, is clear and fresh, The only thing I'm sure on is that it's not a cylinder problem.

We could probably work something out with the Cobra for someone who fixes this darn top... lol.
It's about 5 degrees up here and I don't have much to do. Sounds like it could be the pump. If you are in florida, I found a couple at junk yards and you could get a used pump for 40 bucks according to their price list. Here's the one with a couple SLKs https://www.lkqpickyourpart.com/locations/LKQ_ABC_Pick_Your_Part-196/recents/. Might not work but it's worth a shot for 40 bucks.
 

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Super Moderator UK SLK 55 AMG 2007
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28,182 Posts
After that, you could take a shot at flushing and filling the system with new hydrallic fluid. Here's a good post on it (though sadly it degenrates later on). http://www.slkworld.com/slk-r170-class-diy/25664-roof-hydraulic-pump-draining.html If that fails to do anything, it might be time for a cylinder rebuild. I've never used him, but this is reported to be 'the guy' for cylinder rebuilds. https://www.tophydraulicsinc.com/en/20-r170-slk

Finally, anyway you'd loan your 427 ac cobra for a day or two? (Asking for a friend).

If by 'degenerates' you mean the missing photos?
I've tried fixing, to no avail.
I've pm'd the original poster to see if he can help.
 

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Premium Member 2005 SLK55 AMG; 2005 SLK350
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5,065 Posts
Emergency relief= brass fitting that, when opened fully, prevents pressurization (and allows manual raising and lowering). If it is loose, your pump will lose pressure across the board.
 

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Super Moderator UK 2002 SLK320 Blue
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3,085 Posts
I'm wondering if the mechanism is stiff? When was the last time the hinges and so on were greased? You *may* find this is all you need to do. See the thread on Gummi Pfledge that everyone refers to.

As you can see from the attached, the pump is powered by a motor and this motor is driven by a relay. It's therefore possible that the relay is cruddy and needs a clean or replacement.

N10-3.JPG

A1 Instrument cluster
A7/5k1 Relay
A7/5m1 Motor
A7/5y1 Main valve
A7/5y2 Trunk lid cylinder
M10/3 Left front power window motor (voltage supply)
M10/4 Right front power window motor (voltage supply)
M10/5 Left rear power window motor
M10/6 Right rear power window motor
N10-3 Combination control module
N47 Traction system control module
S69/1 Vario roof "closed" limit switch (right lug)
S69/2 Vario roof "locked" limit switch (right rotary tumbler)
S69/3 Vario roof "locked" limit switch (left rotary tumbler)
S69/7 Left trunk lid "closed/locked" limit switch
S69/8 Right trunk lid "closed/locked" limit switch
S69/9 Trunk lid "open" limit switch
S69/10 Retractable luggage cover "closed" limit switch
S69/11 Vario roof "open/lowered" limit switch
S69/12 Trunk lid rotary tumbler/trunk lamp toggle switch
S84 Vario roof switch

The vario roof is controlled by an electro-hydraulic system. The system consists of the following main components:

One hydraulic unit with two solenoid valves and five hydraulic cylinders as well as nine limit switches, four power window motors, one control module and one control switch.
 

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846 Posts
As above, I would suggest change the relay on the side of the pump as the contacts do burn. This could cause a high resistance in the power feed to the pump. The cost of a new relay from MB is small and good idea to change it every so often anyway before it gives trouble.
 

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Registered 2005 SLK350
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113 Posts
Discussion Starter #20
Thanks everyone, I think I'll replace the relay and check the emergency relief first. I'll look up the part number for the relay and try and locate the relief too.
 
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