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2003 Mercedes CLK430 Cab
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Discussion Starter · #1 ·
I have a 2003 CLK430 Cab (w208), which has the convertible top and roll bars not operating. The dealership tried to reset it thinking it had to do with going over speed bumps to fast. That didn't work. I then took everything out of the trunk area to get to the convertible top motor. Once there I could see I was very low on hydraulic fluid. I then removed the little bit that was left and replaced it with new fluid. Then tested the top, as my buddy held down on the top bottom up front, I could see the fluids draining down to almost empty again, but never found any leaks or fluids around or under the car. I am wondering if there is a leak in one or more of the hydraulic fluid lines now. If so, is there a way to test each line to see which ones may need to be replaced? And how do I go about replacing them?

I would really appreciate any thoughts or suggestions you may have. Thanks!
 

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2002 CLK 320 Cabriolet
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I have a 2002 clk320 and has similar problem. But I found the leak at the hydraulic valve under the trunk/cover lid. You must remove the trim to see it. I don't know how to fix it however, it's rather weird with two small tubes loosely attaching to the valve body with two clips. I think they should be secured with nuts or something more rigid than these two thin metal clips!
 

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03 SL Kleemann, 97 SL320, 95 E320 cab, Tesla X, Ferrari 360, etc
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Which hydraulic cylinders, valves, or lines usually leak first

I have a 2003 CLK430 Cab (w208), which has the convertible top and roll bars not operating. The dealership tried to reset it thinking it had to do with going over speed bumps to fast. That didn't work. I then took everything out of the trunk area to get to the convertible top motor. Once there I could see I was very low on hydraulic fluid. I then removed the little bit that was left and replaced it with new fluid. Then tested the top, as my buddy held down on the top bottom up front, I could see the fluids draining down to almost empty again, but never found any leaks or fluids around or under the car. I am wondering if there is a leak in one or more of the hydraulic fluid lines now. If so, is there a way to test each line to see which ones may need to be replaced? And how do I go about replacing them?
MalibuEstatesBroker,

congratulations on making good progress on your own! For all future readers who are thinking about checking the hydraulic fluid level, or who are ready to flush the fluid and/or upgrade the two most notoriously failing cylinders, here is an awesome DIY prepared by fellow BenzWorlder 'joetwa':

http://www.tophydraulicsinc.com/W208 Case Cover Lock and Rear Bow Lock Replacement.pdf

Here is the order in which the hydraulic components typically start to leak:
1) Rear bow lock cylinder
2) Case cover lock cylinder
3) Remaining cylinders
4) Roll bar valve in the left lower corner under the rear seat

There is a diagram showing the location of the cylinders and the pump attached to the bottom of this post.

MalibuEstatesBroker, it is most likely that one or both of the lock cylinders are leaking in your case - check those first. The hydraulic lines are the least likely to be bad.

The good news is, the upgrades from Top Hydraulics make the cylinders truly better than new ones, on account of the far superior seal material used. We rebuild the roll bar valves, as well.

I hope this helps, and please keep us posted,

Klaus

Top Hydraulics | Rebuilt Convertible Top Hydraulic Cylinders - Top Hydraulics, Inc
 

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03 SL Kleemann, 97 SL320, 95 E320 cab, Tesla X, Ferrari 360, etc
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Rear bow lock, hydraulic cylinder, and attached lines

I have a 2002 clk320 and has similar problem. But I found the leak at the hydraulic valve under the trunk/cover lid. You must remove the trim to see it. I don't know how to fix it however, it's rather weird with two small tubes loosely attaching to the valve body with two clips. I think they should be secured with nuts or something more rigid than these two thin metal clips!
sharo,

welcome to the forum! I'm glad you already found the problem. It appears that you are referencing the rear bow lock assembly, which is accessible from the trunk and located in the middle forward of the trunk lid. Again, here is 'joetwa's awesome DIY for removal of the lock assembly if needed: http://www.tophydraulicsinc.com/W208 Case Cover Lock and Rear Bow Lock Replacement.pdf

Here is an image of just the rear lock assembly: http://www.tophydraulicsinc.com/100...-exchange-rear-bow-lock-cylinder-assembly.jpg. Please keep in mind that you will likely have the other locking cylinder failing, as well; it locks the storage case cover down. http://www.tophydraulicsinc.com/101...-exchange-rear-bow-lock-cylinder-assembly.jpg

As far as the hydraulic lines go, they are well taken care of, the way they are fastened. At maximum operating pressure of some 3000 psi, there is about 40 pounds pushing against the tiny cross section of the hydraulic lines where they enter the cylinders, and the clips are quite sufficient for that. As a reference, we first got one of those clips to fail once we pressurized a similar cylinder to some 13000 psi...

Klaus

Top Hydraulics | Rebuilt Convertible Top Hydraulic Cylinders - Top Hydraulics, Inc
 

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1987 Mercedes Benz 300 TD Turbo, 2002 CLK 55 AMG
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Hi Klaus,

I purchased a 02 CLK 55 recently and was investigating fluid types for the soft top.
My reservoir looks similar to the one in the PDF (near empty). Thanks for sharing this with us as I was headed for the dealer again for fluids.
I have a 124 with Hydraulic suspension. Is the rear shock repairable or is there an aftermarket alternative other than pneumatic (air)?

Cheers, Mike
 

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03 SL Kleemann, 97 SL320, 95 E320 cab, Tesla X, Ferrari 360, etc
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Find the leak!

My reservoir looks similar to the one in the PDF (near empty). Thanks for sharing this with us as I was headed for the dealer again for fluids.
Mike,

congratulations on your recent purchase! I think the main advantage of having a choice in top hydraulic fluids is that you can order online and not have to make a trip to the dealer. The price difference is somewhere around $10/quart, and you need only a quart for CLKs.

However, I'm sure you are aware that you need to find the leak. It isn't going to plug itself, and you don't want the pump to run dry. The fluid doesn't smell that great once it's soaked into you trim panels, either. Thus, please identify the leaking parts - most likely one or both of the locking cylinders. The smart thing to do, is to have them both upgraded while you are at it. :)

Klaus

Top Hydraulics | Rebuilt Convertible Top Hydraulic Cylinders - Top Hydraulics, Inc
 

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1987 Mercedes Benz 300 TD Turbo, 2002 CLK 55 AMG
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I had some mercedes Hydraulic fluid out in the shop.

Topped the resivoir off this morning and tested the soft top function.

Oh He!! yea, It works like new except for the hydralic fluid leaking onto the deck-lid.

Once again thanks for posting this info, I will be logging into TopHydraulics inc.com soon

All the best, Mike
 

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2003 Mercedes CLK430 Cab
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Discussion Starter · #9 ·
Convertible Top Hydraulic Fluid

I wanted to follow-up and let everybody know I was able to fix the problem with the leak. I found the leak behind the back seats. Once removing the bottom seat and back seat, I could see hydraulic fluid on the bed of the seat area, which I cleaned up.

You will see the Valve Block for the Rear Headrest/Roll Bars on the right side in the middle (silver block with 2 brass solenoids on top of it) See Pic 1. I removed the Solenoids from the Valve Block using a Allen Wrench. First loosen the Allen Bolts, you will need to undo two nuts in the back (size 10 wrench) then remove the Allen Bolts completely, lightly pull the Valve Block away from the wall to remove the Solenoids (lifting upwards). Once they have been removed, you should see 3 o-rings attached, one of which will be damaged. I didn't notice mine being damaged till I tried removing them, one of them just came right off. Sometimes there will be noticable damage to the o-ring. From what I have heard lately, it's the lowest (1st) o-ring that is usually damaged and needing replacement. I would suggest replacing the o-ring that is damaged. If the others are okay, I would leave them alone. All three o-rings are different sizes.

Don't go to Mercedes as the don't carry the correct quality o-rings for hydraulic fluids. You will need o-rings made with polyurethane or something of comparable quality that works well with hydraulic fluid. I would suggest going to a local industrial parts supply facilty or plumbing parts facility, bring the o-rings with you so they can measure them for exact size. Keep in mind, if the o-ring you purchase is too small, it may be flush with the wall of the Solenoid. Slide your finger along the Solenoid wall and feel the other o-rings, you will feel a little bump as you pass over them, that's how it should be. This keeps the Solenoid from rubbing against the interior wall of the Valve Block.

*When re-installing the new o-rings, make sure you put hydraulic fluid all over them before putting them back on the Solenoid.



To remove the back seats, first remove the bottom seat by lifting it up from just below the front of the seat (where your knees would be if you were sitting in the seat), it pops up and out and then snaps back in when putting them back in. For the Back seat, along the bottom of the back seat, there are two bolts (one on the left side and one on the right side) about where your lower back would be when sitting in the seat. Remove both bolts. Then there are two small bolts under and behind where the speaker is. They are screwed in from the back (reversed), you will need to feel for these using a 10 wrench in the opposite direction to remove them. Then pull out the arm rest, you will see a soft metal plate, pull from the top and you will see two phillip screws that need to be removed. Once all this is done, I would suggest having two people lift the seat upwards.


If you have any other questions, feel free to message me. Good luck!
 

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03 SL Kleemann, 97 SL320, 95 E320 cab, Tesla X, Ferrari 360, etc
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Roll Over Bar Valve Failure Pattern

MalibuEstatesBrokers,

thank you for sharing your experience with the forum. I am concerned that your o-ring replacement is only a temporary fix, and will share some of my own experience below. Please do not misunderstand me - it is good if the o-ring replacement worked for you, and I am not at all trying to knock your accomplishment.

Top Hydraulics has rebuilt scores of these valves p/n 1248001678 - see Roll over bar valve rebuild service - Top Hydraulics, Inc.

The typical symptom for roll bar valve failure is erratic behavior of the roll bar/rear head rests. Typically, they will not stay down and ratchet up slowly. In most cases, such as in yours, there is fluid leaking out of the valve. This will also lead to slow movement of the top, or no movement at all.

The first time I tried to rebuild a CLK roll bar valve, I thought it would be a simple o-ring replacement, and we could offer the service for a really low price. That wasn't it - the few times that we have actually seen bad o-rings in the solenoids, the o-rings had only failed either as a result of a bad solenoid valve, or because someone had already opened the valve and damaged the o-ring upon replacement.

I am not saying that you damaged your own o-ring, or that it is impossible for your fix to last. I would just like to raise a caution flag and request that you follow up if the o-ring fails again, or possibly give the forum an update after a year or so if the o-ring replacement turned out to be a permanent fix.

Klaus

Top Hydraulics | Rebuilt and Upgraded Convertible Top Cylinders, Pumps, Hydraulic Lines - Top Hydraulics, Inc
 

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Discussion Starter · #11 · (Edited)
The first time I replaced the o-rings with Mercedes generic o-rings, which failed after 6 or 7 times using the top. Then I replaced the o-rings with industrial grade o-rings that work well with hydraulic fluid...no problems now. Everything is working as it should.

One thing I don't get is when I emailed Klaus to see if he could sell me just the o-rings and/or solenoids by themselves whereas I can install them myself. His response was he doesn't sell the o-rings and don't have the solenoids. How does someone who rebuilds valve blocks (replacing the o-rings, screens, solenoids) not have these parts available? I get it...he's here to make some money...yet many of us don't want to pay $200 plus shipping both ways when we can replace 1 or 2 o-rings ourselves for $15 for a pack of 10 o-rings. The trick is finding the right place that carries the correct size & correct quality o-rings.

Once I figured out the right quality and found the right size...the top is working great now.
 

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One thing I don't get is when I emailed Klaus to see if he could sell me just the o-rings and/or solenoids by themselves whereas I can install them myself. His response was he doesn't sell the o-rings and don't have the solenoids. How does someone who rebuilds valve blocks (replacing the o-rings, screens, solenoids) not have these parts available? I get it...he's here to make some money...yet many of us don't want to pay $200 plus shipping both ways when we can replace 1 or 2 o-rings ourselves for $15 for a pack of 10 o-rings. The trick is finding the right place that carries the correct size & correct quality o-rings.
MalibuEstatesBroker,

I am perplexed about your statement. I am sorry if my professional opinion in the previous post offended you in any way. I put a lot of effort into my posts on BenzWorld, and I strive to be very accurate. I would appreciate you correcting your previous statement about our communication.

Please check the emails we have exchanged. You have never asked me to sell you solenoids, and I have never told you that we don't have them. I did tell you that we mold our own seals, and I told you twice that we don't sell our seals. I also told you that the rebuild of the valve block typically requires the replacement of at least one solenoid.

As I wrote in my previous post: if we only had to replace a few o-rings for the valve rebuild, then we wouldn't sell the service for $200. In fact, we don't offer a single service to date (out of hundreds offered) that only requires replacement of some o-rings.

If you find your repair successful in the long run, then I would encourage you to publish the exact dimensions and material of the o-rings you purchased, so that others can fully benefit.

Klaus

Top Hydraulics | Rebuilt and Upgraded Convertible Top Cylinders, Pumps, Hydraulic Lines - Top Hydraulics, Inc
 

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Same problem - leaking control valve for head rests/roll-bar

I wanted to follow-up and let everybody know I was able to fix the problem with the leak. I found the leak behind the back seats. Once removing the bottom seat and back seat, I could see hydraulic fluid on the bed of the seat area, which I cleaned up.

You will see the Valve Block for the Rear Headrest/Roll Bars on the right side in the middle (silver block with 2 brass solenoids on top of it) See Pic 1. I removed the Solenoids from the Valve Block using a Allen Wrench. First loosen the Allen Bolts, you will need to undo two nuts in the back (size 10 wrench) then remove the Allen Bolts completely, lightly pull the Valve Block away from the wall to remove the Solenoids (lifting upwards). Once they have been removed, you should see 3 o-rings attached, one of which will be damaged. I didn't notice mine being damaged till I tried removing them, one of them just came right off. Sometimes there will be noticable damage to the o-ring. From what I have heard lately, it's the lowest (1st) o-ring that is usually damaged and needing replacement. I would suggest replacing the o-ring that is damaged. If the others are okay, I would leave them alone. All three o-rings are different sizes.

Don't go to Mercedes as the don't carry the correct quality o-rings for hydraulic fluids. You will need o-rings made with polyurethane or something of comparable quality that works well with hydraulic fluid. I would suggest going to a local industrial parts supply facilty or plumbing parts facility, bring the o-rings with you so they can measure them for exact size. Keep in mind, if the o-ring you purchase is too small, it may be flush with the wall of the Solenoid. Slide your finger along the Solenoid wall and feel the other o-rings, you will feel a little bump as you pass over them, that's how it should be. This keeps the Solenoid from rubbing against the interior wall of the Valve Block.

*When re-installing the new o-rings, make sure you put hydraulic fluid all over them before putting them back on the Solenoid.

If you have any other questions, feel free to message me. Good luck!
Thanks for this post. My top and rear headrests stopped working recently and I could smell hydraulic fluid in the car, so I at first thought that my cylinders were leaking and I needed to get them resealed by Klaus. When I pulled the black separator plate from the trunk area, there was no fluid at all in the area but the pump had very little fluid left in the tank. So I pulled my rear seat and when running the pump via the headrest rollbar switch, I could hear and see fluid gurgling out from the left-hand control valve as in my pictures. I'm going to replace my o-rings and see if that resolves the issue. I don't know if my car ever had the cylinders replaced/resealed. I bought my car used last November and it was a fleet car for an executive at some big company. The car was (and still is) in immaculate condition and had good service records but nothing that specifically said whether the cylinders were worked on. Anyway, I'll fix this and post here again to let everyone know how the repair went. I wish there was a way to tell if the cylinders had been replaced or resealed.
 

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One O-ring replaced and the hydraulic system works again

Success! The leak was caused by a single O-ring in the left-hand hydraulic solenoid as in the pictures. I took the solenoid out and went to ProShop in San Rafael, CA and Vots (the owner) knew exactly about the Mercedes hydraulic fluid attacking O-rings and seals issue and he went to his stock of O-rings and matched one up that fit. I installed it, refilled my hydraulic pump tank, and now the roll-bars and top work.

He didn't charge me anything and wouldn't take any money.

Pro Shop Inc provides a five star auto service in San Rafael CA

One of my coworkers said to me when I showed him the failed O-ring: "Just like the shuttle, right?" That really puts things in perspective.
 

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03 SL Kleemann, 97 SL320, 95 E320 cab, Tesla X, Ferrari 360, etc
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CLKGeek,

thanks for the detailed photo, and I'm glad this worked out for you. Top Hydraulics has rebuilt scores of these valves, and the o-rings were never the root cause of the failure. I haven't even seen one of the o-rings as torn as in your photo. I'm not saying that you are wrong - the o-ring replacement obviously worked for you. It's just that the valve rebuild is normally much more involved.

As a side note, I would like to clarify a myth. The original Mercedes hydraulic fluid does not attack the seals. The same seals without hydraulic fluid around them have a much shorter shelf life. The problem with the convertible cylinders is that their seals decay with time. The seals in the solenoids are made of a different material that is more stable.

Klaus

Top Hydraulics | Rebuilt and Upgraded Convertible Top Cylinders, Pumps, Hydraulic Lines - Top Hydraulics, Inc
Mercedes Cylinders W208 CLK-Class 98-03 - Top Hydraulics, Inc
 

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Klaus,
Thanks for the clarification about the seals decaying with time. I was under the impression that the hydraulic fluid attacked the seals and caused them to fail. Good to know the real scoop.

The O-ring was badly mangled wen I removed the solenoid valve; the damage wasn't caused by me removing it. It is strange that it was that damaged.

I'm still trying to find the service history of my car to see if the cylinders were replaced. The car is new for me, I bought her about a year ago and she was (and still is) in excellent condition. I'm guess that's because what I do know of the car, she was in an executive motor pool, so likely had very good maintenance.

If I do need cylinder rebuilds, I'll be sure to contact you.

mike
 

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Everything Working Now

Well, my replacement o-ring fix lasted all of two days :( It was worth a shot anyway, and it gave me experience removing the valve block and removing a solenoid valve, plus I got a know a good independent mechanic in my area that works on Mercedes, so it was a net positive!

I decided that I was just going to get a rebuilt valve block from Top Hydraulics, which for $200 is a great deal for me since I don't have a lot of spare time these days to keep removing my rear seats, cleaning up the mess of hydraulic fluid that squirts out form a leaking value, and then trying to track down an o-ring that fits. Klaus sent me out a rebuilt block, I removed my old block, installed the replacement, and after connecting the hydraulic lines properly, everything works now - roll-bars and top!

I did have a slight brain-fart and connected the metal lines up to the wrong ports initially, and couldn't get anything to work. Klaus was very helpful troubleshooting with me over e-mail and what the problem finally turned out to be was that for some reason unknown to me, I connected the lines in such a way that the roll-bar stop lines were connected to the ports for the roll-bar cylinder, and vice-vesa, so the system was fighting itself whenever I turned on the pump. Fortunately I had taken pictures of the correct arrangement, and after going through all kinds of troubleshooting including making sure the new solenoids were getting 12V and the coils were good, and making sure the pump was pressurizing the supply line to the block (warning - if you try this, put a wad of paper towels over the end of the line or you will spend the next week cleaning up hydraulic fluid that sprays all over the inside of your car, fortunately I did use the paper towels so didn't have this problem!). So, I took out my phone, looked at the pictures of the old block, and slapped my forehead for being such an idiot. Oh well, live and learn. Connecting the lines correctly made everything work. First I lowered the roll-bars and then opened the top, and raised it, and all went smoothly.

Throughout this whole process, Klaus was fantastic, from shipping out the block quickly to helping me troubleshoot the problem. When it's time for my cylinder rebuilds, I'm going to order them from Top Hydraulics.

One thing that I had a problem with while I was troubleshooting was that my roll-bars had stopped in the raised position, and I used the manual top opening method to try to raise the top, but it wouldn't go past the rear headrests. I had my daughter try to help me manually lower the roll-bars by pushing on both of the brass release plates and pushing down on the head rests but even with both of us pushing, we couldn't make them move. I wonder now if the problem might have been that the pressure in the cylinder was too great and I should have disconnected the hydraulic lines from the cylinder (or block). Given that I had the lines backwards, and even though I released the system pressure using the release screw on the pump, the vales in the block were probably configured to prevent the hydraulic fluid from moving since the cylinder was connected to the roll-bar stop ports.

Anyway, it was all a great learning experience and my first foray into anything hydraulic (other than the really good glass of wine I had after it was all working :)

So, replacing the valve block is really easy, and, assuming you connect everything up properly, you can do the whole operation in less than an hour. Here's a quick guide to how to do it, Klaus also has some detailed instructions that he can send you if you need them:

  1. Release hydraulic pressure in the system by turning the pressure release screw on the hydraulic pump two turns counter-clockwise. You access the screw from inside the trunk by pulling up the carpet material at the back (you don't need to remove the large black metal plate).
  2. Remove the rear seat.
  3. Take a few pictures of the valve block so you can refer to them when you install the new one.
  4. Disconnect the electrical connections to the solenoid valves. The red-marked connection goes to the right solenoid value.
  5. Remove two nuts from behind the valve block.
  6. Remove the two black plastic hydraulic line clip keepers; you'll need these when you install the replacement block.
  7. Move the two clips to the left. They click into each position.
  8. Remove the hydraulic lines. Have paper towels handy since they might leak and you might get a squirt of fluid from the lines and/or the ports in the block.
  9. Unscrew the hydraulic line from the right side of the block. Same note about paper towels.
  10. Remove the old block.
  11. Reverse the procedure to install the replacement block. I like to screw the block into the bracket as a last step since it makes inserting the hydraulic lines into the ports in the front of the block easier if you can move the block around a bit.
  12. Close the pressure release screw on the pump, and add hydraulic fluid if necessary. Some people recommend a flush. In my case, the o-ring leak did the flush for me all over the rear of the back seat so I just added fluid. Note that you have to use the Mercedes OEM fluid or the approved replacement. The dealer charges about $20/quart for this, my dealer gave me a discount because the parts guy says he always gives a discount to people working on their own cars.
  13. Move the roll-bars up and down, make sure there are no leaks.
  14. Open and close the top, make sure there are no leaks and that it operates smoothly. I have read that the first few times after refilling a dry system, there is air in the system which will automatically bleed out, but you'll notice that the top may slam down hard on the windscreen frame when it's being closed. Catch it with your hand so it doesn't damage anything.

And that's it!

Attached is a picture of my old valve block; the one that Top Hydraulics sends is virtually identical to this.
 

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One Week In - Wonderful!

So it's been a week since I replaced my valve block and my hydraulic system is working very well. I lower and raise my top several times a day every day of the week and it has all worked perfectly. The first few times that I raised my top, I had to catch it so that it didn't slam down on the windscreen frame, but after a few days, that resolved and the top now comes down smoothly on the frame. It seems to work even better than when I bought my car a year ago, so I probably was loosing slight bits of fluid from the leaking value until it finally completely failed. I check my fluid level every day (I haven't put back the black plate yet, I'm modifying it for my subwoofer) and so far, the fluid has stayed at the same level. I keep it just at the top fill line, and I check it when the car is level.

I shipped back my core to Klaus on Tuesday and he processed the core charge refund very quickly - thanks again to Klaus and other folks here on the forum for the help in getting this problem resolved.
 
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