Mercedes R129 SL-Class - Chapter 2 - Replacing the Front Lock Cylinders and Front Distributor

[@nomotalkin1]

Your videos are super helpful. Priceless even. Your name rings frequently in the R129 community. You'll definitely get my business when it comes time for me to repair my top. Thank you.

[@johnwhyte9404]

R129-300SL. Just to say a big thanks to Klaus, I contacted him via Email and also managed to call him too! I live in Italy, I sent my cylinders to have the port seals replaced and the whole process including shipment both ways only took 10 days. Thanks Klaus for a great service! All cylinders working perfectly now!

[@scorebooknavigator8789]

The soft top on my 1997 SL500 is working fine now, thanks to this very effective video on how to replace a leaking front lock cylinder. It would have been a disaster to attempt the replacement without this video. I have one suggestion concerning the use of vice grips to remove the cylinder from the lock. I saw the recommendation to use a 7mm wrench. I obtained a 7 mm and observed that it fit nicely on the replacement cylinder, but not the old cylinder on the lock. The problem was that the jaw of the 7mm was wider than the distance between the shoulder on the cylinder and the lock. I could not find a tool narrow enough to engage the cylinder and resorted to the vice grips. I suggest that you design a tool to engage the narrow space between the cylinder shoulder and the lock and include it with the replacement cylinder. This might save some excessive damage due to guys resorting to vise grips.

[@TopHydraulics]

Thanks for the suggestion! We had a few hundred custom wrenches laser cut out of hardened tool steel a number of years ago. The problem was that people liked them so much, they didn't send back the tool...

[@juancable1]

Thank you Klaus for your detailed video. My driver side microswitch was giving me an unlocked signal - with the center console switch illuminated and chiming . In my particular case, following your detailed instructions, I removed the panel. I just simply cleaned and lubricated the assembly without removing the cylinder. Now I have to figure out if N53 (URB) is the reason my roll bar does not function nor my top . 😕 Thanks again for your invaluable videos.

[@VerNick77]

Thank you a lot, from this vid I was able to see that my glass tube was out of its original place, puted it back and bingo! Cheers from Shanghai.

[@SNAJDAN78]

Absolutly fantastic video !!!!!

[@backinthedaybmx7940]

Very good video , haven’t seen this much info on this procedure on KZbin .

[@stevebilenky4059]

Had I seen this earlier I would have known how to remove the mirror and panel to replace my light rocker switches. Excellent details!!!

[@donjohnson4368]

Excellent- clear and concise. Well presented. Thank you for posting

[@Buttbstinkn123]

thanks a ton for making these videos. Going to send you guys my cylinders soon!

[@robertturek2104]

Great video. Do I also need to replace the Front Distributor when replacing the front lock cylinders?

[@TopHydraulics]

Typically, the front lock cylinders leak long before the distributor does. In most R129s, the front lock cylinders have been replaced once already with new ones from Mercedes and it's already time to replace them OEM parts again (OEM parts and DIY resealed cylinders don't last as long as rebuilds from Top Hydraulics). The distributor is now between 23 years and 35 years old, depending on the model year of your car. Its seals fail eventually and there is no telling exactly when they will fail. Typically, they fail after the front lock cylinders are replaced because the hydraulic lines have been wiggled (unavoidably) and that alone could have made the brittle seals fail. Time and exposure to heat make the seals age. If you have a dark colored early to mid-90s R129, then you clearly should replace the front distributor. Conversely, if you have a light colored, late model R129 that has always been a garage queen and hasn't been exposed to much heat, then the front distributor might hang in there another ten years.

[@JutKip]

Thank you very much for r129 series Helped me allot in my dissasembly!

[@michaelprill6626]

How do I deal with Top Hydraulics from South Africa? They are exactly the standard I am looking for.

[@TopHydraulics]

For questions about shipments to South Africa, please contact us directly through our website: www.tophydraulics.com/contact-us

[@alonzocalvillo6702]

I skipped the mirror removal part I saw no reason for it. It made things easier.Also I found out that the black tabs are not interchangable.I was having trouble fitting it in place before I found out I was using the wrong side one .

[@TopHydraulics]

Thanks for sharing. If you didn’t remove the mirror, then you must have left the front distributor A1298000022 as-is, without replacing its seals?

[@discogodfather22]

Do you have to expel fluid from the system first, before working on it?

[@TopHydraulics]

There is no need to drain fluid first and the system is not under pressure when the ignition is off.

[@williambrandt9254]

Very nicely presented. If anyone hasn't purchased their cylinders before I can attest to their quality. Replaced the two front lock cylinders when I got the car 10 years ago (1996 SL 500), and replaced the others about three years later They are still fine What I should have done when I replaced the front lock cylinders was replace the distributor also but I didn't even think about it So it started leaking recently. And when I took the dome light assembly off it literally crumbled in my hands both the outer color-coded cover and the black backing plate for the circuitry That plastic is notorious for being weak with age but I am suspecting that the hydraulic fluid leaking through that assembly and through the distributor really weakened it So anyway the only issue I'm facing is how to get that silly little screw out of the distributor. There was so little space even the L-shaped Phillips is too big But once I get that replaced and I have an order for a new dome light assembly at the dealer-thank goodness they still stock them - it should be good for many years But I want to emphasize that this is a first class company both with seals that are actually better than what came from the factory and first class technical support The moral of this post is to always replace that distributor when you are replacing the front lock cylinders, because once that leaks you've probably ruined a very expensive dome light assembly

[@TopHydraulics]

Thank you for the detailed comment - you are right on! Our cylinder seals should be good for 30-50 years. Your experience is very typical for the timing of cylinder failures in R129s if they haven't been sitting in the sun a lot: Your front lock cylinders failed after 16 years, the rest a few years later, the front distributor after about 25 years. Your point about the dome light assembly is excellent, and it is why we recommend that all cylinders plus the front distributor get replaced at the same time.

[@KamThandi]

Thanks Klaus. Very helpful. Did you drain any fluid out? I would expect hydraulic fluid to leak out from the lines once disconnected from the cylinders?

[@TopHydraulics]

Thanks for asking. We did not drain out any fluid or any other similar prep work. There will be only minimal leakage out of the pipes to the front lock cylinders because these pipes are in a high spot and the pump's reseroir is all the way below the spare tire. The only way you get more than a few drops coming out of the lines is if you move the rest of the top manually while these lines/pipes are disconnected. There will be some fluid dripping out of the front distributor when you disconnect its bottom pipes. Really not more than a few drops, but you want to be prepared and have some cover on your console.

[@olakunleofficial]

How did you unscrew the the Phillips screw for the distributor? I can’t do mine because it’s in an impossible position….

[@TopHydraulics]

Good question. Sometimes, a black metal strip from the windshield header is too close to the screw head to get a Phillips screwdriver in there. In that case, apply some narrow vise grips on the outside of the screw to loosen it up a turn...

[@adoniscastillo]

Hi Klaus, I was able to remove all the cylinders and distributor with your videos. When I removed the distributor, the lines attached to it came off as well Do I remove those lines prior to mailing my cylinders and distributor to Top Hydraulics? Thanks again for all your help

[@TopHydraulics]

Thanks for asking. Indeed, please remove all lines from the cylinders and from the distributor before mailing the parts to us.

[@dirkdiggler69]

I have a 1998 R129 with 55k on it. I’ve no paperwork to say the hydraulic seals have been replaced or worked on. The hood operation works perfectly. Do you think it’s a ticking time bomb or likely to have been replaced already given the cars age?

[@TopHydraulics]

Chances are that the front lock cylinders A1298001672 have been replaced already, as they are far past their service life and they tend to be the first ones to fail due to being in a position where it gets warm easily (and the decay of the seals is a function of time and exposure to heat). Each cylinder has a manufacturing date engraved in it. It's easy to see on the right side front lock cylinder, as this one is turned such that the manufacturing date is on top. The format is week.week./year.year./version.version. For example, a cylinder made during the 48th week of 1997 could have the engraving 48/97/002E. If someone has replaced the seals on your cylinder, that's not great news, as the seals in any DIY repair kit out there are not very good.

[@dirkdiggler69]

Thanks for you detailed reply. I’ll start digging.

[@NikolayPuh]

Hello. Tell me if you know. I changed all the cylinders and everything works well, but the front locks are not locking the roof. Before replacing the cylinders everything was blocking perfectly. What could be the problem?

[@TopHydraulics]

If you have a model year '95+, then the top will not lock in the front if the magnetic sensor between the front lock is not in place, damaged, or disconnected.

[@NikolayPuh]

@@TopHydraulics Where is this sensor located?! tell me if you know. Or maybe you have a photo of him)

[@TopHydraulics]

@@NikolayPuh You saw it when you watched this video. Go to 2:50 in kzbin.info/www/bejne/qqaUZ5usgMxgl5Y

[@NikolayPuh]

@@TopHydraulics yes. I saw it. But I didn’t know that side very important

[@NikolayPuh]

@@TopHydraulics Well, that means without this sensor the front roof shouldn’t work at all. But for me, if I close it from the front with a wrench, and after it opens automatically with a button. could this be?

[@hammondfan2185]

When you order the rebuilt cylinders does it include the distributor? Is it usually necessary to replace this as well?

[@TopHydraulics]

Thanks for asking, that is an excellent question. We offer the set of rebuilt cylinders with and without front distributor. The front distributor typically fails later than the front lock cylinders. Oftentimes, the port seals in the distributor have decayed far enough that they were not leaking before the front lock cylinders were touched , but they end up failing just because the hydraulic lines have been wiggled from removing and replacing the front lock cylinders. If you are planning to hang on to the car, then it would be wise to include the front distributor.

[@adoniscastillo]

Klaus, you’re videos are fantastic. The right front cylinder lock on my r129 started leaking after my car got caught in the rain despite the pano top being installed. Before I disassemble my car to send in all the cylinders, can I raise the soft top or install my panotop in the mean time? I ask because I live in an apartment complex.

[@TopHydraulics]

Thanks for asking - there is a way to manually lock the soft top or the hard top after the cylinders are out. It requires you to re-install the front locks and the rear locks. The locks will normally jam if you try to manually lock them without a cylinder mounted inside. You could experiment with a wooden dowel in place of the cylinder, or an M6 bolt, or some smart way of tying rubber bands inside the latches.

[@zubby00]

When reassembling the latches/lines do I need to "air" the hydrolic lines? I am thinking about all the air stuck in the system before activating the latches again for the first time. Thank you.

[@TopHydraulics]

No worries, the system is self venting. Simply keep the fluid levl in the pump between min and max lines. It takes a number of cycles, but eventually all air will be out of the lines and the front locks won't be quite as noisy when they latch.

[@johnwhyte9404]

Hi, great video's! I recently replaced the seals on the two front locks but now I have a problem with the centre distributor leaking on one side, all the pipes seem to be in as far as I can get them but they still leak oil. Any thoughts please?

[@TopHydraulics]

Thanks for asking. The front distributor is leaking because it’s seals are bad. If you have not replaced the port seals on your cylinders (where the hoses go in), then you will find those leaking, as well. There is no shortcut - all seals must be replaced in the front lock cylinders: the cup-shaped rod seal, the gland seal, the piston seal and both port seals.

[@johnwhyte9404]

@@TopHydraulics Hi, Thanks very much for getting back to me, just to save confusion are you saying that the distributor box has to be removed , taken apart and the seals replaced? I have already replaced the seals on all of the other 12 pistons! (Which I did with the help of all of your video's, great work)!

[@TopHydraulics]

@@johnwhyte9404To make it very clear: yes, the distributor needs to be removed and have the port seals replaced. As should all of your cylinders. The port seals are behind the brass bushings where the hoses go in. They are the same on the distributor as on every cylinder. They are not -rings or x-rings, but a custom, edge-activated shape. We have them custom molded out of Viton. We believe that our port seal design is bullet proof and the ports should be good for at least 50 years.

[@johnwhyte9404]

How do you replace a port seal please and what is it, I havent seen any videos of this anywhere?

[@TopHydraulics]

We make our own tools for pulling the brass bushings without damaging them, which took a long time to get just right. After pulling the bushings and checking them for damage, we replace the old factory seals with new ones that we have custom molded out of Viton (not o-rings or x-rings) and replace the bushings, setting them just at the proper depth. We believe that our port seals are "bullet proof", good for over 50 years.

[@johnwhyte9404]

@@TopHydraulics Ah thanks that answers a lot of the problem' s I am having. I am in Europe, Italy. If I was in the States I would send you my cylinder's for you to revamp for me! Thanks again!

[@TopHydraulics]

@@johnwhyte9404 We ship to Italy almost on a daily basis. We use FedEx International Priority, which takes 2-3 days to most places in Italy.

[@ahmedjomha9352]

It’s a very excellent video I’m looking to replace the kid the O-ring on top I live in Canada and I couldn’t find anybody with Selloum here I was wondering if you know anybody or any number I can reach to get those soaking all rink it thank you

[@karrknutt3842]

Is this mechanism basically the same on the R230 as the R129?

[@TopHydraulics]

Thanks for asking. The R230 and the R129 have vastly different top locking mechanisms. We will have R230 videos soon. In the meantime, you can could look at out videos on the R170 SLK, which has a front locking mechanism largely identical to that in the R230: kzbin.info/www/bejne/hIq3hX2VqrKKrck

[@donjohnson4368]

Does it need to be bled afterwards? Anybody know ?

[@TopHydraulics]

The system is self bleeding as long as there is enough fluid in the pump. While there is air in the cylinders, the front locks will actuate a bit louder than usual, but that's okay. It will take some five or six cycles to get all air out of the front lock cylinders because the ratio of fluid volume in the lines compared to the displaced volume in the cylinders is fairly high. We are talking about a small amount of fluid in the front lock cylinders, on the order of an ounce.

[@donjohnson4368]

@@TopHydraulics excellent- where do I top up the fluid and is there a special fluid for this? Thanks again. Appreciate you taking the time.

[@davidmortensen3915]

Klaus, I notice that your vanity mirrors and sun visor mount trim pieces are all a darker color than the interior. Were those all replacement pieces? All 4 of those pieces on my SL are missing or broken... BTW, my soft top works perfectly since I installed the cylinders you rebuilt for me!

[@TopHydraulics]

Hello David, thanks for asking and congrats on successfully removing and replacing your front lock cylinders and front distributor. Our rebuilt parts should be good for 30-50 years under normal circumstances. To answer your question, the vanity mirrors, rear view mirror and sun visor mount in my '97 SL320 are original to the car - they must have yellowed with time. I am fortunately that they have not cracked. This car has always been in the Pacific Northwest, so the exposure to sun and heat has been quite low.

[@davidmortensen3915]

I wish I’d seen this before I did this by trial and error

[@donjohnson4368]

Hi David. Did you need to bleed the system afterwards? Where do you top it up from? Thanks Jay

[@davidmortensen3915]

@@donjohnson4368 I did not top it up or bleed system. I think it was over filled before I began. project.