Thanks, Don. I'm delighted to hear that.

It turns out I may never get to open the roof on mine this year, since it's officially spring and yet the temperatures still can't seem to break 40 degrees. Ugh.

This after a groundhog's-day forecast for an early spring. Three open-air vehicles, and I'm still stuck under the canvas.

 

Winter is hanging on here too, Dennis. I love it, but my wife is ready to begin dropping the top in her XK8. If the forecasts prove to be accurate, that could still be two weeks away....

 

Hey Dennis, Unbeliviable work you have gifted to us! Thanks.......... I have an in-tact system and am curious of how you set up this reservoir in the trunk? Do you have pictures of this by chance? I'm concerned about fluid escaping, causing damage.

 

I was wondering the same thing. I was actually thinking of a way to plug the lines ,maybe some golf tees and clamps, instead of having the outer jacket of the lines sitting in fluid which it was not designed to do.

 

I'd think that once the lines are drained/ semi drained you could couple the hoses together with a hydraulic fitting and the air compression would be unlikely to effect the manual latch operation.

 

Thank you, Mick99. I'll try to get you a photo soon.


Gents,

To each his own of course, but my view would be ...

- Plugging the hoses is not suitable. When we operate the latch manually, the piston in the ram moves, and whatever is in the hoses -- air or fluid -- wants to move with it. If the hoses are full of fluid, nothing can move with the hoses plugged since the fluid is not compressible. Even with some (or all) air in the hoses we get vacuum in one hose, pressure in the other. These are felt by the hose fittings and latch seals (which we may be trying to protect) and also oppose the latch movement.

- Similar with joining the hoses together. Worst case is if all fluid, no air, in the hoses. Again nothing can move since the fluid is not compressible and the displacements on the two sides of the piston in the ram are not equal. If there's some or all air in the hoses, same problem as with plugging but less severe.

I think Norri is right: in practice joining the hoses together would be OK if we've got virtually all of the fluid out of them. (But leaving fluid in the hoses will make it easier to go back to hydraulic latch operation at some point if you might want to do that.)


Overall ... I don't see a reason to think that the fluid will attack the jacket of the hoses in my "Poland Spring" reservoir (the fluid lives happliy in the plastic reservoir on the pump after all) but if that's a concern, I think it better to leave the hoses open-ended to drain into some kind of fluid catcher rather than connect them together. I think plugging the hoses would not be a good way to go.

 

Dennis07

Just finished your mod, as my latch hose developed a leak at the elbow in the truck. I actually bought the new hoses, but with work constraints haven’t had the time to do the work. Works like a charm! I did order plugs for the latch lines I disconnected in the truck, to prevent any residual fluid leaks.

As you know there was a minimum buy, so I have an extra set of caps and plugs if anyone is interested. I’m located in Las Vegas.

Dan

 

Thanks for the info. I think you've put my mind at ease about something. In the post immediately above ... I was concerned that plugging the hoses might not work out so well.

But it looks like you've done that and all is working OK, correct? Did you do anything special to drain the hoses before plugging them?

 

I may be way off on this but it would seem to me that you would only need enough "space" in the hoses to let the hydraulic fluid move when the latch is being manually opened and closed. I can't imagine that the displacement of fluid is that great.

So losing a small amount of fluid when you initially disconnect from the pump may be advantageous if you are going to plug the lines.

Any thoughts?

 

For sure, the more fluid lost from the hoses before they're plugged, the more easily things will move after they're plugged. If no fluid at all were lost, nothing could move with the hoses plugged.

I don't know the numbers involved, but the diameter of the ram is surely much larger than the I.D. of the hose, so the fluid will move much further along in the hoses than the length of the piston stroke in the ram. At a minimum, we'd have to lose a volume of fluid equal to the displacement of the piston (stroke x bore area) for things to work.

How much is much? Don't know. How's THAT for an answer without an answer?


So: are you now operating with the hoses plugged, and does it work OK that way?

 

Right now I am not operating at all and have yet to tackle the mod. On Long Island so you know how the endless winter has been!

When you say the ram are you referring to the piston that actually moves the top or the latch piston?

I am going on the assumption that the latch and rams that move the top up and down are independent of each other. Otherwise wouldn't there be fluid running out of the disconnected hoses in the trunk when you raised or lowered the top?

Again I don't know much about this system

 

No, I think the big puddle on the ground when I tried to lower the top, pretty much drained the hoses! The reservoir was about half empty when I filled it up.

As a side note, the syringe didn’t seemed to be a very good idea, so I cut a water bottle bottom off, and drilled hole in the cap for a length of clear tubing, and used it like a funnel. Worked fine.

Dan

 

Jeez, I'm sorry guys, I mixed up two conversations ...

Hunter: Have I got this right? You're up and running. You have plugged the abandoned latch hoses, after losing a bunch of fluid from them. The mod works OK this way. All correct?

Lorwood: Right, the rams that raise and lower the top are not in play here at all. The ram I was speaking of is the one above the windshield that operates the latch. Maybe I should be using another name for that.
And amen on the winter thing.

 

OK so we need determine how much "space" is needed in the hose so the latch can operate while keepng enough fluid in the hoses to keep them from drying out.

Is the simple solution to operate the latch manually once opened and once closed when you first disconnect the lines thus removing the fluid that would normally be displaced and then plug the lines?

 

Aha. If the hoses are to be plugged, then I think your idea gives us the starting point, the minimum fluid to be removed. But still, once the hoses are plugged, we're going to be compressing air in one hose, pulling vacuum in the other when we manually operate the latch. I don't know what that's going to feel like in practice unless somewhat more fluid is removed. Also, we're leaving full-time pressure/vacuum in the system.

My own preference is to have the hose ends submerged in a reservoir --or left open in some sort of fluid catcher -- which eliminates all the uncertainty here. Plugging these hoses or joining them together is just not a match for what the ram is trying to do in pushing fluid around. (But the reservoir/fluid catcher idea seems to be the proverbial lead balloon.)

 

Keep in mind that the system is a push – push. If you plug the hoses than the pressure in the hoses will not be equal leaving you the possibility of pressure in one of the hoses. You do not want pressure on the hose that open the latch as you are going down the road. Leave the hoses uncapped and isolate them so dust and debris. a rag and plastic bag will do just fine.

 

OK I see what you and Gus mean by not wanting to leave one of the hoses pressurized either with fluid or air.


I also like the idea of keeping the hoses lubricated.

What I don't like is the idea of fluid "slopping around the trunk"

Maybe I can fabricate a more elegant reservoir using a master cylinder or some other closed container where the hoses are sealed through through the side walls of the container and the container itself is somehow attached to the car (Wheel well or another appropriate attachment point.)

 

That would be a great contribution. My own crude prototype leaves lots of room for improvement!

The more I think about it, I would really try to discourage anyone from plugging the hoses or joining them together. Every time the latch is operated in such a system, we're fighting pressure / vacuum to some extent. Nothing to be gained that I can see, as there are other ways to avoid spilling fluid.

 

I think we may be being overly cautious, the only difference in displacement is the cylinder rod, I think the over pressure / under pressure created would be minimal.
The only way to know for sure is for someone to try.

 

I prefer to error to the side of caution. Sorry!