SL/R230: Slow top, no leaks, no fault reports




I bought an Icarsoft MB V2.0 today and it reports
’313 solenoid valve and pump outputs OK - yes’.
I am sucking out hydraulic fluid from the pump in stages (emptying the reservoir) and topping up with the correct MB fluid. The ‘old’ fluid looks clear, unsoiled. No sludge comes from the bottom of the container.
What am I looking at? Could someone previously have used a different fluid, that is now a bad cocktail with the correct fill? Is there a cylinder that is constantly in open connection with the pump, that could be leaking internally, waisting pressure?
Tips would be appreciated!
I am new to the Icarsoft tool, obviously. Am I missing something there?




Top Hydraulics explained on this forum how to test, onboard, four cylinders for internal leaks. Halfway I decided to give up, as two bolts that need to be loosened for the test are obstructed by some hydraulic lines. While at it, I noticed that the lines 20 and 21 can be moved about (see 2 seconds video). No signs of leakage. Is this a problem?
Last edited by Frederick NL; May 7, 2019 at 12:02 PM.
Another possibility is a weak hydraulic pump. To investigate that you need a special adapter from M-B and an hydraulic pressure gauge.
When I bought my SL500 in '06 the roof took about 23 seconds to complete a cycle. By '13 it took perhaps 90 seconds.
I checked the system with Star Diagnosis and a pressure gauge and found nothing out of specification, and so there was nothing to fix. Somehow for no apparent reason after a few years the top got faster, and now it might be 17 seconds to complete a cycle.
moretech




Finding someone with SDS seems the logical next step
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Without a pressure gauge and the ($2000?) test kit SDS can not absolutely pinpoint a leaky cylinder. My advice is to remove the hydraulic lines as explained in my post from c. one year ago.
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”You can check for internal leakage with a simple test.
Have the roof closed and the trunk lid open. Use a screwdriver to close the latch on the trunk lid so that the roof controller does not recognize the trunk lid is open. Access the numbered hydraulic lines going to the roof pump and remove lines 30, 32, 33, and 34. Have someone activate the roof closed switch while you watch for fluid coming out of the disconnected lines and valve block. There should be very little or no fluid seen at all. Significant fluid from line 30 indicates a leaky front lock cylinder, 32 a leaky tubular frame cylinder, 33 a leaky left tubular frame lock, and 34 a leaky right tubular frame lock. Significant fluid from any of the exposed ports on the valve block suggest it is faulty.”
I have the trunk liner out, to allow the hydraulic lines for more play, disconnecting them is next. My understanding is that I remove the retaining plates, which exposes ALL the lines. Will they all pop out (#100 will be under pressure, I know)? Do I have to wrestle them out of the block, and later on, how skilled a job is reconnecting them to the block again? Should the retaining plates and the ports and lines be perfectly clean, free from oil?
I’m intimidated by the prospect of creating a mess...
The four lines are easily removed and re-installed in the block.
I would expect there to be no hydraulic oil evident when you access the block. Yet if you do see oil, I wouldn't be concerned unless you suspect there is a significant leak. You do need to be concerned about keeping dirt and other contaminants out of the hydraulic system.




That was a very tough job. I tested the four lines and none of them leaked. That puts the suspicion on the pump and the valve block. Costly....
Last edited by Frederick NL; May 14, 2019 at 01:31 PM.




Last edited by Frederick NL; May 16, 2019 at 12:13 PM.
For the years that my roof was very slow I had a SmartTOP module installed. That greatly eased the annoyance of the slow top, since I didn't have to hold the control switch and was free to assist the movement of the top.
Someone mentioned air in the system. Possibly that is the case and a certain set of circumstances must be in place to purge the air.
Last edited by bobterry99; May 16, 2019 at 07:55 AM.




Gents and ladies, I shall need your good thoughts and well wishing, because I just phoned the regional MB dealer to let them fix the probem. Don't want to get stuck with a stagnant roof during our summer holiday travels. Appt is early June, because their specialist is on holidays now (so there's still time for any surprise-me-solutions...).
I predict air is in the system, somehow.




I am planning to operate the top today. I am assuming there is a little air in the system, especially around the new cylinder. Is there anything I need to do to get the air out...some have said just "operate the top several times until the air is worked out of the system." Is there an air release valve on the pump I need to loosen, or does just "operating the top" do the job by itself?
Sorry, just not familiar with working with this system. Any suggestions appreciated. btw, 2009 SL550.
Thanks,
Reid C.
Last edited by CorAegean; Aug 3, 2021 at 10:30 AM.







