spilok

All of a sudden, the hardtop on my SL500 goes down very slowly, and sometimes stops. I have to keep pushing the control down. Then, of course, the top comes out slowly too. It used to take about 15 seconds. What can I tell the Dealer to check and correct? I know some of you may have had this problem.
I'm afraid it's going to get stuck halfway up or down in operation.
My '03 SL 500 just turned 10,000 miles.

Stan

bobterry99

According to a service bulletin a possible cause is: "An air bubble is present above the upper intake hole in the expansion reservoir of the hydraulic unit" (picture). The solution is to unbolt the pump, prop it up with the motor end of the unit raised, and then operate the roof. If this does not solve the problem the next step is to check the hydraulic pressure using the Star Diagnosis system.

If you go to the dealer I'm very curious to know what they tell you. I think they may tell you that you need new hydraulics. If that happens the bill will probably be expensive, but a much cheaper alternative would be to do the repairs yourself.

I hope you'll post back with updates of your progress.

spilok

Thank you for your response. I sure will report back to the forum.

Where exactly is this hydraulic pump?

Stan

bobterry99

The pump is in the bottom of the trunk to the left of the spare tire. The picture below shows the pump unbolted and propped-up to run and eliminate the air bubble...

spilok

My dealer looked at mine today...you can see the hydraulic motor control in the trunk on the left side of the spare. My fluid was very low for some reason. It's going in the shop on Thursday. I hope my top is fixed by just the addition of fluid. We'll see. Where it's leaking, I do not know. There certainly are no drippings on my garage floor.
My Sl500 is an 03, but I bought it with only 7800 miles on it. It sat for a while in the former owner's garage. The top worked perfectly when I got it, but I believe that by operating it when I got it, that after so many years not being used, the fluid was quickly used somehow. This is my theory. It's not based on any real knowledge, but I'm trying to figure out why the fluid was so low. The hydraulic cylinder in the trunk is transparent...so you can easily see the level of the fluid. Mine was WAY below where it should be. Perhaps dry seals or something. I'm looking forward to Thursday night when I pick the car up. Hopefully, my slow top problem will have been solved.

Stan

StephenK

I hope it is a simple fix for your car. As much as we all seem to want the newest out there, nowadays cars, computers, software all seem to have beta versions out on the first try and as consumers we seem to pay for it.

spilok

Thanks. I hope so too. Fortunately, I bought an all inclusive warranty when I bought the car. Good for 36,000 miles or 5 years. No deductible. I'm sure that if it is more serious, it will be covered.
All I know is...it's getting warm in in Pennsylvania, and I WANT my SL 500 totally operational.

Stan

BlackonBlack

Can you give an idea of how sluggish is it? Mine seems to be slower than it used to be, takes about 19 seconds for mine. From fully open to fully closed ie. the window snaps up. I too need to check on the hydraulic fluid. Is this something we can check just by looking at a MAX and MIN indicators? Where is the resevoir to begin with?

spilok

I think 16 seconds is normal. Yours doesn't sound slow. Mine hardly moves at all. It could take as much as a minute or longer of constanty holding up the lever on the console. You can actually hear the hydraulic pump starving for fluid.
I'm not sure how it's refilled or even where. That's why it's going to the dealer on Thursday. I'm sure hoping that's the real problem.

Stan

BlackonBlack

Please let us know what the dealer says. At over a minute, that's quite slow. I hope you find the solution. Good luck!

spilok

I'll let you know as early as Thursday night or Friday at the latest.

Stan

spilok

Well,
The Dealer fixed my top. That's the good news. It supposedly works perfectly after they filled the hydraulic container in the trunk and bled the air out of the system. I have a loaner car, and I will pick up the SL500 tomorrow morning.
The bad news is that they do not know WHERE the hydraulic fluid has gone to. Because it's an oil, it certainly didn't evaporate. My only explanation is that I bought this car last November with 7800 miles on it (an '03) and it did sit in a garage and not driven regularly. When I bought it...it must have been close to the point where the fluid was low and after some use, perhaps the seals were dry, and absorbed the fluid. I don't know. They checked all six of the hydraulic pumps and they were not leaking. They are stumped. But all I can do is take the car, enjoy it, and see if the fluid level goes down again. There are no spots on my garage floor, and they spent the entire day working on it. Because there were no parts involved, I will pay approximately $169.00 for labor. Had a part been replaced, my bill would have been $0 because I have an all inclusive warranty which covers the hydraulic pumps and everything.
Actually, I'm glad to pay the labor fee because this technician worked hard on it. I will also tip my service writer and mechanic at the Dealers as I always do.
I'll report again after I get the car and check it for myself. I WILL check the fluid level regularly to see if it happens again.
I'm up for suggestions.
Any Mercedes technicians out there? I'd love to hear your theories.

Stan

spilok

It's been about 2 weeks now since my "sluggish" top was fixed. It's still working great, but the hydraulic fluid level in the trunk canister is INDEED GOING DOWN. It's only a matter of time when the problem starts again. Guaranteed! I put a black mark on the side of the hydraulic fluid canister where you can read the level, and it's down about a quarter of an inch. WHERE CAN IT POSSIBLY BE GOING? The Dealer found no leaks and he bled the system. There are no wet marks on my garage floor, and the car sits for days at a time. I am absolutely at a loss for ideas. When I stand outside the car and operate the top with my key, I do notice that the hydraulic pump in the trunk sounds rather noisy when operating.
I will give it back to the dealer again, but they will be frustrated too when I call....since they worked with the car for a few days.

Hydraulic fluid is in a "closed" system. Any ideas out there?

Stan

tiggerfink

It sounds like you have a leak. If the leak is not occuring at the connections or the devices, it may be a busted hose. Just follow the hoses.

spilok

Thank you for the reply. I will mention this to my Dealer. I plan to call the dealer tomorrow and tell me to get me a "loaner"....and take the time necessary to find the leak. It has to be somewhere, I agree. I will tell him about your "hose" theory.

Stan

tiggerfink

One of the hydraulic hoses may have been pinch. I believe there are two hydraulic hose to each hydraulic pump. I think my SLK320 has 3 hydraulic pumps and 6 hydraulic hoses. It should be the same for the SL500.

spilok

Would a "pinch" STOP the flow of hydraulic fluid? Mine seems to be disappearing.

Stan

tiggerfink

yes and No. A pinch hose may have a small hole.

spilok

Well....Good news. The Dealer found the culprit. Indeed, the Left vario roof (open/close) hydraulic cylinder showed evidence of leaking. It seems that the piston appeared rusty and the seal was cracked. Using a dental mirror, after exposing this piston in its awkward position, they were able to see the leakage. However, there is no puddle beneath it so somehow the minute amounts of hydraulic fluid somehow escaped this area.
How did this happen? Don't know. This car, though sat unused for quite a long time. I bought it with less than 8000 miles on it last year, and the previous owner had 10 cars in a thermostatically-controlled garage. I'll never know how it happened, but at least I will have a good summer without fear of the top freezing in half-opened position.

Thanks for all your suggestions and help.

Stan

tiggerfink

Sometimes the leak will follow ther hose to another location in the car.

spilok

That's true. The dealer told me the back end of the car is pretty much tore apart....but not to worry, it goes back together quite well. God, I love German engineering! Thought I'd have the car back today. Seems they got the wrong part fed Xed. My dealer called me and said that the RIGHT hydraulic cylinder was packed in a box labeled LEFT. They should have the correct one tomorrow, but with the Holiday weekend coming up, and the job is a 4 hour job, I'm hoping I get the car by tomorrow evening. They assured me they are going to try to make it happen.
What an "Adventure" this has been.

Stan

spilok

All fixed now,and they gave me the old part. Without the warranty I bought, this was a job that cost over $800. I saw the bill! Fortunately, it didn't cost a cent. Hydraulic fluid now filled, and I look forward to a sunny Summer.

Thanks for all your input.

Stan

mikey100

You just made me feel REALLY great I purchased (for what I at the time thought was a fortune) a M-B Extended Warranty on my C.P.O. SL500.

And just think ....... From what others have told me, it COULD have a LOT larger total than just $800.00 !

Glad all is good now wih yours. I have to have mine looked at for what I feel are the same symptoms when it goes in for Service B in a month or so. My nearest dealer is about 50 miles away.

Mike Lulejian
Lake Oconee, GA

spilok

Mike,
If you suspect it's a hydraulic leak...it's easy enough to check. Take out the floor mat in the trunk, and then remove the large foam cover to the left. It's covering the hydraulic pump. You can see the level of the fluid on the side of this translucent cylinder. There are 2 marks near the top that are supposed to be where the fluid level is correct. You probably need to use a flashlight to shine on the side of the pump in order to see it sufficiently.

If your fluid is where it's supposed to be, then you probably do not have a hydraulic leak.
Correct me if I'm wrong, forum members. At least that's my understanding of the problem.
Stan

tanmervin

If there's insufficient fluid, please tell me what sort of hydraulic fluid to use and also how do I top up? Thanks!