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Convertible Top Cylinder Leak

437 Views 13 Replies 9 Participants Last post by  Clay_in_ABQ
What can cause the cylinders for the convertible top to leak? Holding the switch (open/close) too long? Having the top down for an extended period of time? Too much air in the line? Other?

I replaced one cylinder about 5 years ago. I replaced the other cylinder, the lines, and fluid a couple of months ago. There is a little bit of air in the lines, but I cycled the system 3-5 times to get out as much air as possible. I had the top down for a long time after because it was warm weather. I raised it a couple of weeks ago. Now, the 5 year old cylinder is leaking. Wondering if the problem is with the (dumb) operator.

Are there gotchas or no-nos in operating the top which may cause a cylinder to leak? Appreciate any help/guidance y'all can provide!
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I had to replace both top cylinders in one of my 66 Convertibles last year. I know the cylinders were replaced about 20 years ago by a previous owner and the car sat for at least 15 years before I acquired it. There could be any number of factors that could cause the cylinders to leak. Mine failed more than likely due to non-use and the seals became dry and brittle. Any corrosion on the ram, which is exposed when the top is up will accelerate the deterioration of the seal when the top is operated. Also, the previous owner could have used cheap imports, so that could come into play. Obviously you don't want to cause unnecessary stress my holding the switch too long when the top is fully up or down. Due to tolerances and differences, it's best to replace the rams in pair. Type F ATF fluid is recommended.
 

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I can only hope, based on the what we know about "Chinesium" parts, I don't have to replace mine. It's original to the car, as far as I know, and I've owned mine since the early 80s.
 

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Discussion Starter · #5 ·
Thanks @image98! And agree with @Woodchuck comment. Since I just replaced the one side in August, I'm going to replace the 5 year old side alone this time. @image98 if I hold the switch too long, will it cause a leak? If so, how do you know the right time to stop? Putting it up or down, I usually see movement when it sounds like the motor is working a little harder. I stop when the movement ceases. I would think these would be a little more idiot-proof, but maybe I'm a better idiot 🤣
 

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When it bottoms out in either direction you can hear a distinct change in the motor sound... that's when you stop. Holding it slightly longer than need be won't kill things, but isn't really recommended. Like brake lines, air in the lines is potentially a killer. You want to bleed the system completely when replacing components or changing out the fluid, as well as using the proper fluid.
 

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After over 25 years of owning my '65, I'm of the opinion that there's nothing you can do with operating that will make it leak. I make it a practice to leave my top down all summer long and that hasn't caused me any issues. When I do operate it up, I generally hold the selector "UP" until I get the latches locked in, because my top is pretty taut and if I don't do that it the latches won't catch the holes in the a-pillar brackets.

I did have a cylinder leaking several years ago that I had to replace....but knock on wood....no problems since.
 

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Discussion Starter · #8 ·
Thanks @HoosierBuddy & @gt350sr! I didn't figure it was too temperamental, but thought I'd ask. The motor I have only has a bolt to get the fluid in the reservoir, so it's a bit tricky to bleed. This is the only convertible I've ever had, so I had to ask if I am the problem. I guess I know what I'm doing this weekend (after Christmas lights) 🤣
 

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There are two grades of cylinders available, same goes for the hydraulic lines.
I questioned [email protected] about them and ordered the pricier ones along with a pump rebuild kit.
I was surprised by the amount of crap inside the pump reservoir, probably original fluid in it.
 

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After over 25 years of owning my '65, I'm of the opinion that there's nothing you can do with operating that will make it leak. I make it a practice to leave my top down all summer long and that hasn't caused me any issues. When I do operate it up, I generally hold the selector "UP" until I get the latches locked in, because my top is pretty taut and if I don't do that it the latches won't catch the holes in the a-pillar brackets.

I did have a cylinder leaking several years ago that I had to replace....but knock on wood....no problems since.
Yep, I have to hold mine until the latches are closed, too. Mine are still original to the car (I bought it in '84), so I've been lucky so far.
 

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Discussion Starter · #11 ·
@kechke what does AOD mean?

@Clay_in_ABQ you guys posting that you have original cylinders really makes me wonder if it's operator error on my part, :) Another possibility is a lack of use on my part. Both times a cylinder went out it was after re-starting consistent use after a long period of the car sitting in garage (years). 🤷‍♂️ If I lose another one, I think I'll have to go with the higher grade cylinder from somewhere. I appreciate all the feedback from everyone!
 

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@kechke what does AOD mean?

@Clay_in_ABQ you guys posting that you have original cylinders really makes me wonder if it's operator error on my part, :) Another possibility is a lack of use on my part. Both times a cylinder went out it was after re-starting consistent use after a long period of the car sitting in garage (years). 🤷‍♂️ If I lose another one, I think I'll have to go with the higher grade cylinder from somewhere. I appreciate all the feedback from everyone!
AOD is automatic over drive, don’t know why my I pad put that in there, I corrected it.
 
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When I bought the car, I topped off the levels on everything, top cylinders included. I haven't even thought about it in the ensuing 38 years. Maybe I should check.... Top still works, though. Generally, don't go cheap on replacement parts. That is my inclination, but I'm fighting it.
 
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