calicant

The roof was making a strange sound from the rear left side while going down. Dealer has failed to discover why the hydraulic fluid reservoir needed to be filled twice in the last year. I don't want to find a failure after the extended warranty runs out so what is the best way to discover the source of a hydraulic fluid leak?

SoCalSLKDude

It's surprisingly easy! Remove the headliner.

Open the top to resting position. There are 9 screws - 3 in front, and 3 on each side, very obvious, except the last one on the sides, farthest back of headliner.

Wash hands , remove all screws, leave side AND BACK frames in place, pull liner straight forward to remove from channel.

Now you can see everything. While you are in there, remove the clear plastic boots that are on the switches, that way you will not experience the dreaded "trunk opens, pump stays on, nothing else happens" syndrome when you try to put the top down!

Oh, then look for fluid inside the headliner, and around the hoses and cylinder.

Top Hydraulics

calicant,

have you ever found out where the leak was coming from?

The SL has nine hydraulic cylinders. The seals in ALL these cylinders will eventually fail, unless your car gets wrecked prematurely. This is a common problem with almost all modern convertibles - Top Hydraulics actually upgrades thousands of cylinders per year. We call our rebuild service "upgrade", because the seals we are using to replace the OEM seals will make your cylinders better than new - they will last longer. Our upgrades cost a fraction of the replacement cost for inferior OEM parts.

The seal material in all the SL cylinders is the same, and it decays with time. The chemical reaction is accelerated with heat and/or humidity, and especially if the wrong fluid was used. Usually, the front lock cylinder fails first.

Important: Do not use "stop-leak" type additives or hydraulic fluids other than OEM or FeBi 02615, or you are jeopardizing your whole hydraulic system!

When you are ready to have your cylinder(s) upgraded, you will have to remove them with the hydraulic lines attached, and send them in. There is no way around that at this point. Do not let yourself be talked into replacing the seals yourself with O-rings: O-rings are for static applications, and they won't hold up long to a piston sliding through them, if you can get them to seal at all...

Our average turn-around time is one day.

There is a bunch of labor involved in removing the cylinders, because you have to remove a lot of trim pieces to trace the hydraulic lines all the way back to the pump in the trunk. However, it mostly takes patience, and you can save a lot of money by doing it yourself!

Attached below are a picture of the locking cylinder inside the top roof panel, and a piston rebuild example.

Hope this helps,

-Klaus

klaus@tophydraulicsinc.com

Rick SL55

I have to replace the roof hydraulic front lock cylinder. I bought it over 9 months ago and haven't replaced yet. Any other tips and pictures on how to replace the roof hydraulic front lock cylinder?
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Klaus Witte, Top Hydraulics, Inc.
Any DIY instructions that can apply for the SL (230).
Thanks

kustom2k1

Where did the fluid end up going? Did you find stains anywhere? Guess we need to add this to the list of preventive maintenance!

Top Hydraulics

Rick SL55,

thanks for asking. I have done this once on my own R230, and didn't take photos of the process at the time (outside of the one posted a few days ago, showing the cylinder mounted in the roof).

As SoCalSLKdude writes, you can get access to all the screws mounting the headliner by moving the top close to its highest position. Ideally, you want to move the top forward from there and put a large, soft buffer between the top and the windshield. For example, an economy pack of toilet paper rolls.

Removing the cylinder from the locking mechanism it pretty straightforward. I seem to remember that you have to remove the locking mechanism to get good access to the pins holding the cylinder in place.

Removal of the trim piece around the rear window takes some time, because you need to figure out where the tabs are located and how to unsnap them. It's easy when you know how; hope somebody else on this forum can help us out here, or you can post some photos when you're done...

From there, you are down to removing the trim pieces in the left side of your trunk, in order to trace the lines all the way back to the pump.

The hydraulic lines have numbers stamped on them in red ink. These numbers correspond with numbers embossed on the pump's ports. The lines are attached to the pump via a retaining plate that gets loosened with an Allen wrench.

I personally would attach a string to the end of the removed lines and pull them back from the pump, all the way up to the cylinder location. That way, you will have the string(s) just where the lines used to be, and you can attach the new lines to the string again and pull all the way back to the pump for installation.

Hope this makes sense, and good luck!

Btw, I'd like to buy your old cylinder, so that we can add it to our core exchange inventory and offer this service for other members in the future.

-Klaus

klaus@tophydraulicsinc.com

Rick SL55

Klaus
Thanks for the info & tips.