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Registered 1998 SLK230
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59 Posts
Discussion Starter #1
Hi all,

I would be most grateful for any advice on troubleshooting a problem with the variable roof system. I have searched online for the same problem I am experiencing, but have yet to find anything identical.

Here's a summary : I have recently re-installed a set of 5 professionally re-built hydraulic cylinders for the variable roof. Before powering the roof, I manually lowered the roof to ensure it wasn't catching on any wayward cables or wires. It went up and down without issue. Next, I installed a new car battery, and then pressed the red power button rearwards to lower the roof.

The main and vent windows went down without issue. Then the trunk began to rise. However, it only rose 8-10 inches and then stopped.

I couldn't see anything that was physically preventing the trunk from rising fully. From the advice of forum member efair, I was able to manually pull up the trunk. I pulled out all the trunk panels and went looking for any obvious problems.

I used a screwdriver to manually engage all switches that are involved the variable roof. There didn't appear to be anything preventing contact with the switches.

My next plan is to get the multimeter out and do some testing.

Please correct me if I'm wrong, but I thought all the steps involved in making the roof go up and down are performed in sequential order. With this in mind, I would anticipate problems would tend to arise at the very end of one sequence, and before the start of the next sequence. But in my case, the problem is occurring in the middle of a sequence.

Any insight into how dumb I am or advice on how to proceed would be greatly appreciated.

Cheers
 

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Registered 1997 SLK230 Kompressor
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329 Posts
I did the cylinder replacement last year without problems. Apart from switches which may be the obvious issue, I suppose you are 100% certain the hydraulic lines are back in their correct holes in the pump? Some of the labels on my lines were very very faint and I remember having to double check I'd got them right.
 

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Super Moderator UK SLK 55 AMG 2007
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28,731 Posts
Don't be thinking you're dumb.
Many of us battle with items our experts find simple.
So many switches involved, it is a case of patience in tracking down the one offender
amidst a count of 20 or so (maybe more, what do I know).
 

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Registered 1998 SLK230
Joined
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59 Posts
Discussion Starter #4
I did the cylinder replacement last year without problems. Apart from switches which may be the obvious issue, I suppose you are 100% certain the hydraulic lines are back in their correct holes in the pump? Some of the labels on my lines were very very faint and I remember having to double check I'd got them right.
Thanks for the suggestion, Rofa. It's a good reminder for those who are rebuilding/replacing the lines.

Yes, I double-checked the hydraulic lines were in the correct holes. I found using a magnifying glass to be helpful, as the numbers on the plates that cover the holes were difficult to read. Maybe it's an age or literacy thing...
 

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Registered 1998 SLK230
Joined
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59 Posts
Discussion Starter #5
Don't be thinking you're dumb.
Many of us battle with items our experts find simple.
So many switches involved, it is a case of patience in tracking down the one offender
amidst a count of 20 or so (maybe more, what do I know).
Cheers
 

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Premium Member 2005 SLK55 AMG; 2005 SLK350
Joined
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5,136 Posts
Please correct me if I'm wrong, but I thought all the steps involved in making the roof go up and down are performed in sequential order. With this in mind, I would anticipate problems would tend to arise at the very end of one sequence, and before the start of the next sequence. But in my case, the problem is occurring in the middle of a sequence.
You are mostly correct here, but there are no absolutes... e.g. if a nearly-broken wire is flexing as the lid moves, it can stop mid-stroke.
 

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Registered 1998 SLK230
Joined
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59 Posts
Discussion Starter #8 (Edited by Moderator)
You are mostly correct here, but there are no absolutes... e.g. if a nearly-broken wire is flexing as the lid moves, it can stop mid-stroke.

@efair : I really do appreciate your continued help.

The red power light wasn't doing anything when the trunk lid stopped eg. no flashing

The hydraulic fluid level in the pump reservoir is at the maximum fill line. I tried powering the roof at least 10 times in the hope that maybe the lines hadn't fully pressurized yet. No luck there. Same result every time.

Your suggestion about the wires is a good one. I will inspect them.

Would hooking up an SDS scanner be of any benefit in tracing the problem ?

Cheers
 

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Super Moderator CA 2012 SLK55 AMG w/P30
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14,211 Posts
When you mention someone, you need to add an @ in front of their username so they get notified. I added for you (y)
 

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Premium Member 2005 SLK55 AMG; 2005 SLK350
Joined
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5,136 Posts
So the red light just stays solid red, and the pump continues running, but the lid does not lift fully? How close to the apex does it rise? (If it's within an inch you might be able to adjust the yokes on those cylinders)
 

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Registered 1998 SLK230
Joined
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59 Posts
Discussion Starter #11
So the red light just stays solid red, and the pump continues running, but the lid does not lift fully? How close to the apex does it rise? (If it's within an inch you might be able to adjust the yokes on those cylinders)
@efair : Yes, the red light stays solid the whole time, and the pump continues to run after the trunk stops (providing I am still pushing the button).

The lid only rises 8-10 inches and then stops. I would estimate it needs to go at least another 10 inches before reaching its apex.
 

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Premium Member 2005 SLK55 AMG; 2005 SLK350
Joined
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5,136 Posts
Since both sides seem to be equally impacted I'll guess the pump is not producing sufficient pressure. You could scan but I don't think it will reveal anything.

You could remove the relief valve and the two solenoids on the pump, and check their o-rings. There are many other internal seals that can fail so it's not a complete check but maybe...
 

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Registered 1998 SLK230
Joined
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59 Posts
Discussion Starter #13
@efair

You bring up another potential culprit who was sitting lower on my list of suspects.

I will try to get my hands on an ammeter, and test the pump. It may take a few days, but I will report back with results.

Thanks again
 

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Premium Member 2005 SLK55 AMG; 2005 SLK350
Joined
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5,136 Posts
So when you manually pulled the lid up/back, and your roof continued "normally" thereafter, did the pump have any difficulty moving the roof and rear windcreen from fully open to fully closed, and/or vice versa? Reason for the ask is that this movement is the highest energy required - the roof is the heaviest component and has to move the furthest - so if there is no trouble there, it's probably safe to assume the pump motor is working.
 

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Registered 1998 SLK230
Joined
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59 Posts
Discussion Starter #15
@efair

After I manually pulled the roof, I just proceeded to pull apart the interior trim and started looking for obvious problems. In retrospect, I should have tried powering the roof again.

I'll put the trunk interior panels back in, pull the roof back, hit the power button , and see what happens. Will report back.

Cheers again !
 

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Premium Member 2005 SLK55 AMG; 2005 SLK350
Joined
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5,136 Posts
There is no need to put the trunk panels back in. I presume you say that because the "partition extended" switch... just jumper the two harness pins for that switch - this will fool the roof module into thinking the partition is always extended.
 

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Registered 1998 SLK230
Joined
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59 Posts
Discussion Starter #17
@efair
Doh !! Too late. But what a great tip ! I will certainly take your advice to jumper the switch from here on.

Ok, I manually pulled the trunk lid as far as it would go, and then pushed the red power button. The roof unlatched, but did not move after that. The power button remained solid red the whole time.

When I pushed the power button forward to lower the trunk, nothing happened -the trunk didn't move.

I think your earlier suggestion about the pump being the problem certainly merits further attention. I have tracked down an ammeter, so hopefully will be able to render a verdict on the pump in the next few days, once I get the ammeter.

Cheers
 

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Premium Member 2005 SLK55 AMG; 2005 SLK350
Joined
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5,136 Posts
You could have multiple issues here - do you have access to a good scanner?
 
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