I am new to the MBWORLD site and am interested in buying 2002 SL500. I have read about the hydraulic issues and wonder what % of these 2002's would be prone to having a problem.

Is this something that inevitably happens to most SL500's?

THanks, Andy Simon

 

Not sure what info you have gotten, is it something 02 specific? I'm fairly new to 129's myself, and since nothing has broken so far on my 99, I've only read about problems and the fixs.

From what I have read, the seals in the hydralic cylinders will eventually leak. This seems to be a problem with all years, not just 2002.

Having the dealer replace the cylinders with new ones was been quoted at a few thousand dollars in several forums.

There are at least two other alternatives. from businesses that specialize in rebuilding them instead of throwing them away. The savings from rebuilding is significant, if I remember correctly, about $500 or so rebuilds them all. You just need to have them removed and reinstalled, either DIY or an indi.

Do a forum search on the SL top hydralics and read what's already there. The biggest issue is what condition they are in when you buy the car, as it should affect the purchase price.

If I remember correctly 10 years has been alluded to before they start to leak, and thats probably very variable. Usage is also a factor, where not being exersized at a regular frequency can hasten the seals deteriation.

Again, I've just been reading and not replacing yet, so other experts will hopefully chime in with some real hands on advice.

One last thought, the 129's have always been something of a passion for me, and even though I know the hydralics will need replacing at some point, I still bought mine. Sooner or later I'll spend anywhere from $500 to $1500 perhaps to upgrade the cylinders. Sounds like a lot, but then again your good for another ten years or so, and you get to drive a 129 all that time.

The most important things you can do are to buy a 129 that has been well maintained and is completly documented. Also have a pre-purchase inspection done, the $200 inspection fee could save you thousands and lots of frustration. Even if you find some flaws and still want to buy, the information helps with reducing purchase price.

Good luck..

 

Welcome Andy-
Your questions about the 2002 MY and hydraulics are both good ones. I have a '99 myself that I wanted at the time because it had the newer 113 engine as does the 2002. Frankly if the 2002's had been selling for what I could afford, that's the MY I would have gotten.

That aside, the hydraulics are a known 'problem' with the 129 and other MB convertibles that use them(124's) to move the top, rollbar, top cover etc.. IMO, you should expect a 10-15 year life out of the hydraulics, primarily the seals, internal to the dozen or so hydraulic cylinders, that do the actual work. The seals will eventually fail and begin to leak with the front pair that release the top latches usually failing first; I replaced my front pair with rebuilt cylinders about 4 years ago. The major contributors to seal failure are age and heat, not use. That's the reason the front pair usually go first as the sun is virtually always on the front of the car and the cylinders in the headrail are subject to that heat.

The good news is that there are multiple cylinder rebuilders that can rebuild yours when necessary for about 1/3 of the cost of new ones from the dealers. On a scale of 1-10 for things to checkout when looking at one of these, the top function is a 10. In any car you look at, insist that the top be lowered and raised at least 5-6 times. Watch for smooth functioning and inspect the front header for hydraulic fluid leaks, and around and under the car for the same.

And finally, speaking of inspecting one of these...ohollenbeck is absolutely right about getting a pre-purchase inspection before even thinking about buying one of these. In fact, I'd first find a QUALIFIED MB independent tech in your area that will end up doing some to all of your maintenance work, and make him your new best friend. The shop/tech you choose must have the Mercedes Star Diagnostic System that is indespensible in maintaining these cars, plus, if he's the best around, he'll know which of his customers are selling theirs, which ones are good values and which to stay away from.

These are great cars, if you get a good one to start with; if you don't they're a money pit. Keep in mind, 'There is no such thing as a cheap Mercedes', and 'The most expensive Mercedes you'll ever own is the one you bought without a qualified inspection first'!

Good hunting-

Bob

 

Thanks so much for the suggestions. They all make perfect sense. So far, I have not found a well maintained SL, but there is no rush on my part. I like the idea of finding a local tech who will help me find a car, inspect it and keep it running .

Regards, Andy

 

Andy,

I hope you have found your dream-SL, or at least you haven't given up on finding the perfect one yet. I am attaching some hopefully useful diagrams, pictures, and links to DIY instructions below.

Here are a few comments on the previous posts - please excuse the length:

Yes, this is inevitable to any SL, unless the car goes to the wrecking yard prematurely. As Bob writes below, it is a chemical reaction that is inevitable and gets accelerated with temperature. It also gets accelerated by exposure to water, Ozone, or additives in the hydraulic fluid.

We are at this point upgrading many full sets on '02s already. Actually, practically the same seals have been used in later models SL, CLK and SLK, and it is not uncommon for us to be upgrading all cylinders out of 05 model years already.

The good news is, when you find that perfectly maintained '02, you may only have to replace the two front lock cylinders, or it has been done already.

The better news yet is that this should be a one-time expense when you use the right rebuilder - the seal makes the difference! OEM replacements would last you only some 10 years again, and our largest competitor who was the first one on the block uses practically the same material (we have rebuilt plenty of them again already).

Top Hydraulics uses a proprietary seal material and combination that is much more resistant to decay accelerated by heat, water, Ozone and additives.

I can tell you from experience as an SL fanatic that it feels great to know your top will work flawlessly every time you pull or push that button!

ohollenbeck,

thanks for your comments. You are right, the life span of the seals is very variable. Even in clean systems, OEM seals can fail as soon as after five years, and they can last as long as 20 years in well maintained vehicles that haven't been in a hot climate. There is a theoretical advantage to moving the top every few months, but I believe that this has no noticeable impact on your OEM cylinders' life span. It is more important to change the hydraulic fluid every 3-5 years. And thanks for using the word upgrade - you got the point!

Bob, I personally think that model years '99-'02 have the best engines, although many argue that '97 and '98 were better with the last of the M119 engines. I currently own MY's '97, '98 and '99 and have a bias towards the engine in the '99. One of my employees has a '99 SL500 with 245k miles on it, and it's going strong.

Certainly, an MY '02 has the nice look and all the plastic is a bit newer...

Just a small amendment to that: ALL convertibles with hydraulic tops have this problem, and over 90% are using the same seal material that is used in the R129s - up until today! My theory behind the reason for continued use of the same old failing seals is not so much planned obsolescence, but a monopoly in Northern Europe and less first-hand exposure for the engineers who live in very moderate climates. We are currently upgrading the convertible cylinders for 16 brands, all using the same seal material/supplier as Mercedes.

Bob, thank you for being neutral about the rebuilders choice. I know you have had a good experience with the machinist who was first in replacing the seals when he was the only alternative to MB. His seals are a bit beefier than MB's, and being almost the same material they will theoretically last a bit longer than the OEMs under equal conditions.

Yes, I fully agree! Thanks for taking the time to make this point.

Since I'm the hydraulics guy, I will post below some links to detailed DIY instructions, a diagram of your cylinder locations, and a comparison of old to rebuilt cylinders.

All DIY instructions cover inspection, removal and installation of the respective hydraulic cylinders in your convertible top:
Front lock cylinders: http://www.tophydraulicsinc.com/R129%20Front%20Locking%20Cylinder%20Removal.pdf
Rear lock cylinders: http://www.tophydraulicsinc.com/R129%20Rear%20Locking%20Cylinder%20Removal.pdf
Storage cover lift cylinders: http://www.tophydraulicsinc.com/R129%20Tonneau%20Cover%20Lift%20Cylinders.pdf
Storage cover lock cylinder(s): http://www.tophydraulicsinc.com/R129%20Tonneau%20Cover%20Lock%20Cylinders.pdf
Bow extension cylinders: http://www.tophydraulicsinc.com/R129%20Bow%20Extension%20Cylinder%20Removal.pdf
Main lift cylinders: http://www.tophydraulicsinc.com/R129%20Main%20Lift%20Cylinder%20Removal.pdf

Click on the thumbnails below for larger images, or go to http://www.tophydraulicsinc.com/diagrams/r129diagram.jpg for a crisp image.

Hope this is helpful,

-Klaus

klaus@tophydraulicsinc.com