[Fluteguy]

I need to replace the left hydraulic cylinder above the windshield on my 1992 500SL and I have a couple of questions.

1. Is it really that easy? I've replaced the door check strap and changed the oil on my W126 300SD but that's about it. The pictures look easy but.....

2. The left is the one leaking. Can I get away with only doing that one or is it really better to do both?


Thanks!

 

[RedLiner]

Best do both at the same time.

I'm sure that removing and replacing the cylinders is well within the scope of anyone with a basic DIY mechanical knowledge.
There are step by step instructions in the Hydraulic soft top sticky so you should be able to manage the job yourself fairly easily, and of course if you have any doubts or queries just post in asking for guidance.

I'm assuming you are sending the cylinders to Dennis for rebuilding, or are you going to buy one of the seal kits that we now have available and do it yourself?

 

[Fluteguy]

i WAS JUST GOING TO GET THE PARTS FROM A SUPPLIER

 

[SunGuy61]

i WAS JUST GOING TO GET THE PARTS FROM A SUPPLIER

The cost of two rebuilds from Dennis is still less than the cost of one new cylinder from any supplier. That and Dennis' 3yr warranty vs any supplier's 90 day to 1yr(MB) warranty makes Dennis' solution the best thing going. And I absolutely agree with redliner that it's that easy to change these cylinders.

Bob

 

[chriswufgator]

The windshield header cylinders always go around the same time...so you need to do both, since you're just doubling the labor doing one and having go to back in 2 months and do the other one.

In my experience with our 3 R129's, the two in the windshield go first, and the rest will start crapping out anywhere from a year to three years later. So your clock is ticking on those too.

Best/cheapest solution long-term, even though it's more money up-front, is to just remove all of them and have Dennis do his rebuild package ($500 or so) and then reinstall all of them. It's a big job, but once it's done you'll never have to deal with again because the seals he uses don't degrade like the factory seals. You're actually worse off if you use a new MB cylinder instead of having Dennis rebuild them, because you'll just have the same problem again in another 7 years.

If you do it piecemeal, just R&R'ing one cylinder every time another one springs a leak, then you'll be chasing this problem for the rest of the time you own the car, and you'll be ready to pull your hair out. It will also be much more expensive over the long-term, since you're doubling, tripling, etc., labor and shipping costs by having to mail individual cylinders and having to take the same things apart multiple times to address multiple cylinders. Much cleaner to just do it all at once.

Bank on about $1200 as a fair price for the job, including the Dennis rebuilds, but once it's done you're set and won't have to deal with it again.

 

[chriswufgator]

Oh yeah, just to clarify, the price I mentioned in my previous post is if you have an indy do the work for you. If you DIY it, then you're just out the cost of the rebuilds by Dennis, which is only $500.

 

[Fluteguy]

After reading your post I'm leaning towards getting the front ones fixed and then getting rid of the car. I love my 500SL but if it's that big of a problem I'll get rid of it and get a 560SL.

I have a W140 if I have a need to pull my hair out about fixing things

 

[chriswufgator]

After reading your post I'm leaning towards getting the front ones fixed and then getting rid of the car. I love my 500SL but if it's that big of a problem I'll get rid of it and get a 560SL.

I have a W140 if I have a need to pull my hair out about fixing things

It's not a big problem, really, it's just a design quirk. Once you address it, it's done, and you don't have to worry about it again.

Personally, I'd rather spend $1200 and have a trouble-free automatic top than an R107 and have to get out of the car and spend 3 minutes putting it up when it rains, or putting it down when I want to use it. Once you have a fully automatic top, you really won't want to go back.

The thing I don't get is, you're obviously willing to spend $1500 on a single replacement cylinder from MB, but yet you seem very resistant to having the originals rebuilt as good as new by Dennis, where the ENTIRE JOB for the rebuilds plus the mechanic's labor for the R&R of all cylinders, won't cost as much as the single cylinder you're about to buy from MB.

I'm really not understanding this, it makes no sense. :dunno: A lot of us have done the full rebuild through Dennis, including me, and have been very happy with the results. The ENTIRE JOB, for all the labor + the cost of the rebuilt cylinders, was less than you're about to spend for ONE cylinder from MB, and then you still have to pay for labor. :dunno:

 

[Fluteguy]

Problem is that my mechanic is not inclined to replace parts unless he gets them (said something one time about it being akin to taking a steak to a restaurant and asking them cook it for you). Granted it would be cheaper in the long run if I could do it myself but not sure that a car that I drive under 2000 miles a year is worth the cost and I'm not mechanically inclined enough to do anything other than the front ones.

I guess that I was stupid to buy the car in the first place. I know what the costs of my W140 are and I should have assumed that the R129 would be similar.

 

[msmith66]

Don't let Chris scare you about the rear cylinders. If you change the fronts and flush / fill the hydraulic fluid you will likely never have another problem with them. The procedure is very basic and well documented here. I'd say most R129s don't have a problem with the rear cylinders if they are taken care of and used regularly. I have driven ones that did have the problem and you will know it if it happens. Just get the rebuilts from Dennis and have your indy change them then.

If you get rebuilts instead of OEM parts you will have to have your car down for the time it takes Dennis to fix and return them to you.

Remember to renew the fluid with the OEM MB fluid or the Febi-Bilstein. Don't just top it up. Changing my front cylinders cost me a total of $160.00 - pretty cheap in my book.

 

[chriswufgator]

Don't let Chris scare you about the rear cylinders. If you change the fronts and flush / fill the hydraulic fluid you will likely never have another problem with them. The procedure is very basic and well documented here. I'd say most R129s don't have a problem with the rear cylinders if they are taken care of and used regularly. I have driven ones that did have the problem and you will know it if it happens. Just get the rebuilts from Dennis and have your indy change them then.

If you get rebuilts instead of OEM parts you will have to have your car down for the time it takes Dennis to fix and return them to you.

Remember to renew the fluid with the OEM MB fluid or the Febi-Bilstein. Don't just top it up. Changing my front cylinders cost me a total of $160.00 - pretty cheap in my book.

Well...in fairness, I doubt most people KNOW they have a problem with the rear cylinders, it's not that they really don't have a problem.

The rears are located in areas where their leakage runs straight through the drain holes for the soft top storage compartment and drops harmlessly underneath the car. It won't ruin your clothes, smell up the interior, or leave puddles on your seat. And the drains are located to where the fluid drops underneath the middle of the car in between the rear wheels, so you won't notice it on the ground unless you looked at the parking space after you moved it. So most people are probably just unaware they have an issue.

But they DO start leaking, usually a year or two after the windshield header cylinders. It is something you will eventually have to address.

 

[chriswufgator]

Problem is that my mechanic is not inclined to replace parts unless he gets them (said something one time about it being akin to taking a steak to a restaurant and asking them cook it for you). Granted it would be cheaper in the long run if I could do it myself but not sure that a car that I drive under 2000 miles a year is worth the cost and I'm not mechanically inclined enough to do anything other than the front ones.

I guess that I was stupid to buy the car in the first place. I know what the costs of my W140 are and I should have assumed that the R129 would be similar.

R129 costs like 1/4 or 1/2 as much to maintain as a W140, don't worry, you made a wise choice.

As to your mechanic, he may be a nice guy, but that B.S. about parts is ridiculous. Don't believe that line of crap for one minute. I recently stopped using the same indy I'd been using since 2000 over this same issue. It is NOTHING like bringing your own steak to a restaurant, and that's just a catchy-sounding way to conversationally get around the fact that he's basically screwing you. The truth is, if I can walk in with the same EXACT part, made by MB or the same OEM manufacturer, then what's the difference to him? $$$$$ is the only difference.

If your indy is anything like my old one, then you're already paying out the nose for labor, and he probably charges you book time or above for every job anyway, when you know it only took him half that long. His profit should be on doing the work, not raping you on parts that he marks up 1000%. That's double-dipping.

Most good indys that are *fair* won't have a problem with you bringing your own parts. The ones who squawk about it, are always the same ones I have issues with later over labor times etc.

 

[harley03joe]

Question:
I Was Reading The Forum, And My Question Is How Do You Flush And Refill The Top Fluid ?
Thanks
Joe :Smoker:

 

[chriswufgator]

Question:
I Was Reading The Forum, And My Question Is How Do You Flush And Refill The Top Fluid ?
Thanks
Joe :Smoker:

MB tells you that you don't have to. Same B.S. they say about the tranny fluid. Don't believe it though.

Lynn invented a procedure for doing it not too long ago, and it was an easy DIY thing. Wouldn't take you but about an hour. PM him and see if he will forward you the instructions.

 

[Fluteguy]

What about the Lucas stop leak that I see on some threads?

 

[chriswufgator]

What about the Lucas stop leak that I see on some threads?

LOL. That's a touchy subject around here. There's a guy who used it and said he had O.K. results with it, but people kinda jumped on him for ghetto-rigging it. Both sides had good points.

Personally, since we're never getting rid of the car that sprung the hydro leaks last year, I figured we'd just grab the bull by the horns and do the job the right way. I had a sneaking suspicion that the StopLeak would just be prolonging the inevitable...

 

[RKH]

What about the Lucas stop leak that I see on some threads?

Some said it works, but most of us don't want to risk our R129 to find out for ourselves in case it doesn't.

 

[msmith66]

MB tells you that you don't have to. Same B.S. they say about the tranny fluid. Don't believe it though.

Lynn invented a procedure for doing it not too long ago, and it was an easy DIY thing. Wouldn't take you but about an hour. PM him and see if he will forward you the instructions.

Or, as a novel idea you could try searching the forum! I searched for flush and hydraulic and found 2 pages of responses. I will not repeat them here because it is all covered in the stickies.

And I still don't believe that problems with the rear cylinders - or any of the cylinders for that matter is a given for every R129. It is a common problem but I bet there are many R129s that never have the problem. And, if you have a rear cylinder leaking, there is no way you can miss it! There will be a puddle of fluid on the floor wherever you actuate the top and it will eventually all pump out leaving the top and the roll bar inoperable. I test drove one that did exactly that. I had the car for 3 hours and knew this was a problem.

Trying to tell someone to perform a $1000 or $1500 repair job based on the chance that it could go bad in the future just isn't the right thing to do. His engine will eventually wear out - should he replace that too? You've scared this guy out of the joy of owning his R129 over something that isn't even wrong with it.

Nimrod - I'm not too far from Lexington (at least after May anyway) If your back cylinders go bad I'll drive down and help you fix them in exchange for dinner.

 

[Fluteguy]

I know the best German restaurant in Lexington!


Or Steakhouse if you prefer.


The Lucas Oil hydraulic oil boost and stop leak is a moot point now. There's not a drop to be had for 200 miles!

 

[msmith66]

I know the best German restaurant in Lexington!


Or Steakhouse if you prefer.


The Lucas Oil hydraulic oil boost and stop leak is a moot point now. There's not a drop to be had for 200 miles!

Don't bother with it. Replacing the cylinders is the correct way to fix this problem.

Your MB dealer stocks the OEM fluid and it should cost you around $30 for 2 litres of it which is the amount you need to flush and fill after you change the front cylinders. LH-M is a mineral based oil and I would not put anything other than the OEM or known Febi equivalent in the tank. When you see what comes out of your tank you will understand why we recommend you change it. Some members have ran assays on the old oil to see if its ph changes but it doesn't seem to. It does oxidize severely however and this might be the cause of seal failure. There is much less surface area to hold back the pressure on the front cylinders and I think this is why they usually fail first.

The only real trick in doing the front cylinders is having the proper tools. You'll need some 1/4 drive tools and some good old fashioned metric allen wrenches.