R129 Hydraulic top cylinders

[dennis300sl]

Hi folks, I thought some of you may be interested that I've found a way to rebuild the top cylinders with the 6mm rods. I have just finished rebuilding the tonneau cover cylinders and I will be removing the rear latch cylinders tonight. (all of my cylinders are leaking)

The repair is fairly simple. The bad thing is that Mercedes used a bastard size piston rod seal that I haven't been able to find without being custom made. I did find a very close match at http://www.epm.com, but I did have to machine the cap that holds the seal from 13mm to 14mm. I'm a machinist so machining the cap wasn't a problem.

If anyone is interested I'll have some seals leftover ( $75 minimum order at epm!!!). I can either sell just the seal for $4 or if you send me your used cylinder I'll install the new seal, new o-ring on the seal cap, and polish the piston rod for $30 plus shipping. If there's enough interest I'll purchase more seals.

Next I'll be tackling the main top cylinders.


seal size is 6mm ID x 14mm OD x 5.7mm thick U-CUP Polyurethane Rod Seal

Dennis Ficken
Olathe, Ks

'91 300SL
'88 300E

[pep]

If your're reffering to the hydraulic valves or cylinders that work to bring the convertible top up and down, that are located on top of the windshield, then we are talking about the same thing. My 1994 sl500 cylinder or cylinders are leaking and AT the map lights above the rearview mirror and through the sunvisors hinges you can see the hydraulic fluid filtering when I engage the mechanism to bring the convertible top up. I don't know which cylinder is leaking the most or if both are leaking. I also need information on how to remove them so that they may overhauled or fixed. MB does not have as of yet a repair book or CD avilable for this R129 model. Thank You for the INFO. PEP

[bobterry99]

Won't take you more than 45 minutes. Use a phillips to remove the plastic trim around each of the two openings where the top latches to the windshield. Now the top cover can slide back to expose the hydraulics. What you should find is that the hydraulic cylinder which actuates the lock is causing the leaking. Disassembly from this point should be intuitive. No need to bleed the system when you finish. Phil sells replacement cylinders through PartsShop for $125. Ask for part #129-800-16-72.

[pep]

THank You for the info on how to access the hydraulic cylinders and where to purcahase them. Am assunming that I lost a substantial amount of hydraulic fluid and I need to know how it is replaced back into the system, since you've told that there is no need to bleed the system. Also, when I remove or loosen the whetherstripping above the windshield to access the cylinders, should I just go ahead and replace it with a new one. I live in Florida and you can imagine how much rain we get here, am talking about big storms, hurricanes,etc. I've experienced a few raindrops getting in through the left front corner of my drivers side window between the hardtop and the glass. Maybe you can suggest something better to remediate the situation. The weatherstripping looks kind of wasted, after all it is a 1994, with 88,000 miles. Again, I thank You for all your help. PEP

[bobterry99]

Oh, you don't remove any weatherstripping. You slide the metal top cover back to expose the hydraulics.

[pep]

Thank You for input, I was going the wrong way. Can you provide me with the how to put the hydraulic fluid back into the system so that is fully loaded to be operational and if by any chance you have replaced the weatherstripping before, you can give me some guidance as to removing and replacing it. Thanks time and time again, PEP

[Kebowers]

You guys this is a ridiculous failure!!

I remember having a 1963 Chevy Impala convertible red with white top, red leather interior 327 4 Bbl 300 HP (wish I still had it, worth more than my 94 sl-600). The POWER top system worked flawlessly, faster, and NEVER leaked--either water around the windshield or oil from the cylinders. Can't MBZ make /supply a real hydraulic system?

I grew up on a farm--with LOTS of hydraulic cylinders, owned and maintained a Citroen SM and all its hydraulics for 24 years, and never have I seen so many seal failures as owners of SL's report. S*&**ty parts from MBZ (supplyers) is the cause. Poor engineering the root cause.

[bobterry99]

I can't find any documentation explaining the procedure, but it surely must be done at the hydraulic pump located under the spare tire.

[ronjon365]

Hello, I need help please. I have one of the hyrdaulic seals busted on my convertible top. I called Mercedes and well they wanted an absurd amount of money for the part($768.00 plus Tax). Does anyone know where I could either get the seal replaced on that part or if I can get that part somewhere else cheaper. It is called the Cylinder Fabric Retaining Bow/Left(drivers side)---Lamens terms ---it is the cylinder that to me me looks like a robot---it is located at the back of the top---not for the tonneau but for the top. It is the cylinder that is at the majority of the metal framework for the top. It allows the top to go up and down. It is NOT the one that is in front of the rear wheel well(the big cylinder) but the one above it in the convertible top storage area(when top is down). Please advise. Thanks RJ

[Daytonaman]

Those cyl are avail for around $150. New or used. I have replaced both of those before. There is a video that shows how. One (drivers side) has a limit switch.

[bobterry99]

Originally Posted by ronjon365

Does anyone know where I could either get the seal replaced on that part or if I can get that part somewhere else cheaper. It is called the Cylinder Fabric Retaining Bow/Left(drivers side)

Contact Phil here at mercedesshop.com if you want a new one for $404. I believe the part number is 129 800 17 72. You might also try the "wholesale" parts department at calibermotors.com.

[deejay]

Hi, Denis, I saw youre message and I am interested of buying only the seal. I think all the cylinders have the same size, if it's the case, I am interested to buy 12 seals. I can pay you by pay pal or the way you prefered. I am from Canada. If you can give me youre e-mail adress I can contact you.

[dennis300sl]

Deejay,

I wish that I could help you, but I tried selling only the seals once before and the guy screwed up both of his main cylinders and bow extension cylinders beyond repair. Since then, I will only do the repairs myself so that I can make sure that it's done properly. At $30 per cylinder, the cost is minimal compared to dealer prices and I offer a 3 year warranty on the seals I replace as well.

Dennis Ficken
16285 S. Chester
Olathe, Ks 66062

(913) 390-0506

mercedescylinders@sbcglobal.net

I have a 91 500 sl with 57000 original miles on it. The mileage is probably why I am having all these problems with it. The car is in perfect mechanical and cosmetic shape for the exception my power top is broken. It started in September of last year. I was tweaken and cleanen my car way to extensively and had the top in the upper position and stopped it for me to clean. I the put down the roll bar and doing so blew out my hydrolic pumps in the back of the car my mechanic said. He quoted me a expensive price to repair and I figured I had no options. I took the car in last week to have the repair done and when he took the car apart to fix them he said I now have more hydrolics leakings and he just did not feel comforatble charging me the amount he was going to fix all those to find out when he pressures up the system others will then leak. he was replacing them with new parts. IT WAS GOING TO BE AS MUCH AS THE CAR IS WORTH to repair he said. Can u help me? I dont want to have to do the manually for the rest of my life with the car and its worth nothing with a totally broken top. What should I do?

Originally Posted by dennis300sl

Hi folks, I thought some of you may be interested that I've found a way to rebuild the top cylinders with the 6mm rods. I have just finished rebuilding the tonneau cover cylinders and I will be removing the rear latch cylinders tonight. (all of my cylinders are leaking)

The repair is fairly simple. The bad thing is that Mercedes used a bastard size piston rod seal that I haven't been able to find without being custom made. I did find a very close match at http://www.epm.com, but I did have to machine the cap that holds the seal from 13mm to 14mm. I'm a machinist so machining the cap wasn't a problem.

If anyone is interested I'll have some seals leftover ( $75 minimum order at epm!!!). I can either sell just the seal for $4 or if you send me your used cylinder I'll install the new seal, new o-ring on the seal cap, and polish the piston rod for $30 plus shipping. If there's enough interest I'll purchase more seals.

Next I'll be tackling the main top cylinders.


seal size is 6mm ID x 14mm OD x 5.7mm thick U-CUP Polyurethane Rod Seal

Dennis Ficken
Olathe, Ks

'91 300SL
'88 300E

[Mal]

Theres a whole thread here with pictures and a guy that rebuilds the cylinders for $40.00. Let me find it.



Edit:

here it is:

http://www.peachparts.com/shopforum/mercedes-benz-sl-discussion-forum/160010-94-sl320-convertible-top-problems-hydraulic-fluid-leak-malfunctioning-post1283826.html#post1283826