POLL - Convertible Top Hydraulic Cylinder R&R

[snowbilt]

If it leaked once then they need to be replaced. I am sure the diy link I posted is on this thread. I wish I would have known about dennis fickens he can rebuild them for 30 ea, I paid 110.00 ea for new ones. I have never heard of activating the roll bar making the cylinder leak. I guess pressure on the system is pressure on the system.

[Herr Lou]

This may be as helpful as those having problems...

1) Which Hydraulic Cylinders have you replaced? Front, Rear?
NONE

2) How was the service performed? DIY, INDY, or STEALER?
IF REQUIRED, I WILL REBUILD MYSELF WITH NEW O-RINGS

3) What year did you perform the repair?
N/A

4) What year and color is your R129?
1994 WHITE

5) What City and State do you reside. Just checking for Temperature reasons.
WEST COAST, BRITISH COLUMBIA, CANADA

6) Do you have any additional information that you feel is important to the poll?
140,000 km. LOOKS AND RUNS LIKE NEW. ZERO VISIBLE LEAKAGE ON ANY CYLINDERS.

I suspect that the previous owner (I'm the second) didn't use the soft top much. It's original and other than yellowed plastic windows, looks like new. Last summer was so good here, I probably cycled the top more than 100 times. I'm guessing the moderate temperatures (lows of 0°C and highs of 25°C) may be a factor as well as total # of cycles and regularly changing the hydraulic fluid.

[lynns]

Originally Posted by snowbilt

I wish I would have known about dennis fickens he can rebuild them for 30 ea, I paid 110.00 ea for new ones.

I did a Search of multiple part sites and found the Covertible Top Struts (i.e. Front Hydraulic Cylinders) M-B OEM P/N 1298001672 or O7049-163985 ranging from $110.00 to $149.95. Of fifteen sites these sites had the lowest prices. Don't forget to buy two each or have Dennis Fricken rebuild both for you at $60/pair. Here is the M-B p/n 000989910310 for Hydraulic/Suspension Fluid at $10.06/liter. If you do a complete flush of the system it holds 1.25 liters.

Parts.com

Mercedes Benz - Eugene.

[Bawbag]

Kestas - I am not trying to re-engineer the system, i am just trying to understand which one is the problem the seal material or the hydraulic fluid used ! !

as you wrote:-
"We should stick with the Febi-Bilstein Fluid #02615, and rest assured that the polyurethane seals are compatible with this fluid and fix a weakness in the system, and not try to reengineer the system".
Dennis reportedly uses polyurethane, which the seal engineers tell me is a good choice for hydraulic seals.

but - you also wrote that MB use a polymer called polycaprolactone as the seal material when the vehicle is assembled

"I have some technical info on the seals used in the hydraulic pistons. We reverse engineered the material using FTIR methods and got a perfect match. MB used a polymer called polycaprolactone as the seal material. A quick google tells me this is a biodegradable material that melts at 140°F. It's mostly used in the biomedical industry.

So am i lead to believe that when the R129 was built the seals they were using for all the soft top hard top pistons are of a biodegradable material ??

Baw

[lynns]

Originally Posted by Bawbag

Kestas - I am not trying to re-engineer the system, i am just trying to understand which one is the problem the seal material or the hydraulic fluid used ! !

as you wrote:-
"We should stick with the Febi-Bilstein Fluid #02615, and rest assured that the polyurethane seals are compatible with this fluid and fix a weakness in the system, and not try to reengineer the system".
Dennis reportedly uses polyurethane, which the seal engineers tell me is a good choice for hydraulic seals.

but - you also wrote that MB use a polymer called polycaprolactone as the seal material when the vehicle is assembled

"I have some technical info on the seals used in the hydraulic pistons. We reverse engineered the material using FTIR methods and got a perfect match. MB used a polymer called polycaprolactone as the seal material. A quick google tells me this is a biodegradable material that melts at 140°F. It's mostly used in the biomedical industry.

So am i lead to believe that when the R129 was built the seals they were using for all the soft top hard top pistons are of a biodegradable material ??

Baw

It is my understanding that polycaprolactone is a polyurethane compound. From further readings I'm not sure that it is biodegradable since it is used in Submarine hydraulic systems. But as mentioned earlier if the Mineral Oil has Phosphate Esters, used as a fire retardant then there can be problems with the oil attaching the seals. Febi confirmed back to me that its product does not contain Phosphate Esters.

[SL4Sale]

I have a leaking right rear CT actuation cylinder on a 94' SL500. I plan to remove and send to Dennis to rebuild. This will be the 6th cylinder replaced. The 1st 5 by the dealer $!!! Can you tell me the easiest way to access this part? The cylinder at least in part actuates the hard toneau cover. P.N. 1298000272

Thank you,

BdS

[lynns]

There are a total of 11 cylinders that store the soft top.
$3,896.00 MSRP parts only total from Parts.com . This does not include tax, ship, and R&R labor.
May I suggest that you contact Dennis Ficken and ask the cost to rebuild yours.

You need this tool to rebuild 129800 1772 (left) and 124800 0272 (right)

Please read seal dimensions photo

IDxODxt--Seals
6x13x5----6 each
6x10x4----2 each
16x22x5---2 each
9x14x5----2 each

Diagram#--Parts#-------Seal ID--Seal OD--Seal t---O-ring ID--O-ring OD
---------------------------------------------------------------------------------------
2----------- --2172-----------6mm---13mm----5mm-----13mm------16mm
3----------- --2172-----------6mm---13mm----5mm-----13mm------16mm
5----------- --2072-----------6mm---13mm----5mm-----13mm------16mm
9----------- --1772, 0272----6mm---10mm----4mm-----10mm------13mm
9----------- --0272----------16mm---22mm----5mm-----29mm------33mm
10------------1672------------9mm---14mm----5mm-----13mm------16mm

Please refer to Seal & O-ring dimension for the hydraulic cylinders.

The p/n's below where found at The Russian Parts site.

2 = 129800 2172 , $142.00 each US MSRP
3 = 129800 2172 , $142.00 each US MSRP
5 = 129800 2072 , $240.00 each US MSRP
9 small/upper cylinder = 129800 1772 (left) , $760.00 US, 124800 0272 (right) , $454.00 US
9 large/lower cylinder = 129800 0272 , $670.00 US MSRP main top acuator
10 = 129800 1672 , $147.00 each US MSRP or aftermarket p/n O7049-163985

[sl320man]

I am in the process of 7 cylinders rebult by Dennis:
(2) #2
(2) #3
(2) #5
(1) #9 , because I had the other on replaced by a mechanic

The hardest/most work to remove was the #9. Be careful not to pull the bolt out and drop it into the frame. Very hard to get out.

[edutain1]

I have had , 4 all from Japan ranging from 1992 - 1994 and none have ever leaked or been replaced but had roof part # 1298001772 and
1298001978 replaced in one of the 1993s

[Bagger Lance]

99 SL500 - Drivers side windshield cylinder blew out last week. I pulled both left and right cylinders and shipping them to Dennis tomorrow.

While at it, I went ahead and stripped the covering for the rear storage area and trunk just to get a look at the other cylinders. Thinking about pulling those for rebuild as well.

Need a good description of disassembly process before I dive in. Hopefully Dennis can send me some material.

Many Thanks for this thread Lynns and others. I'm sure to save around 90% the cost by DYI and rebuild!

Love it!

Bagger