Hi, its been a while as my Cat has been doing great. All good things must come to an end.

I lowered my top today and all went fine, I later went to raise it and I can hear the hydraulic pump kick in for about 5-10 seconds then stops. The front latch doesn't raise at all, the roof doesn't move. The fluid is full and is the green fluid.

Any help appreciated.

 

Suspect #1: check to see that the petcock on the pump is fully closed (turned clockwise).

Inspect around the pump (feel around the back too) for any fluid leak that might be just beginning.

 

Dennis, thank you for the response. The petcock is closed I had tried releasing pressure and then trying again yesterday with no success. I see or feel no oil leaking. This morning when I tried it the top went up.

I am not sure why it worked now but I am sure there is something wrong or about to break. I recorded a video of the motor running. the converted file was turned upside down.

 

The reservoir level dropped during the video. Did it go back up afterward?

It sounded to me like the pump was cavitating. If so, it could clear on its own.

Best to keep a close eye now for any signs of oil appearing from the overhead console. Sometimes it's just few drops at first.

 

Next time it does this, hold the top button in the "top down " position 10 seconds while the car is running, then hit the button for the top to go back up.You will be fine.

 

1st time i showed my wife the roof closing the metal bit attached to the latch flicked itself over where the catch goes in - so the roof almost closed but of course couldn't lock - that was fun .... eventually with some fiddling around it raised again - i keep an eye on the latch when it's closing now, u just have to flick the metal locking bit if it gets in the way.

 

Thanks for everyone's responses.

LondonXK8Boy: I have had to pause mine before so the latch is fully opened, not often
but a couple times.

Aode06: Thanks I will try that when it happens again.

Dennis07: Yes, I saw that air or level drop too. it shows full, I wonder if air
got in the system? That's kinda scary to think about as that means Repair! I will
watch at the front for oil and at those connections on the pump. Thanks.

 

I would suggest lubricating the latch and the hydraulic piston that drives the latch linkage. This link will show you what I am talking about.

Link JagRepair.com - A Jaguar Repair Information Resource

 

Gus and the rest of the gang here are amazing and I'm sure they'll have you up and running in no time.


Your video was helpful. To recap, it was working fine and then just stopped working? It wasn't "weakening" over time? If it has weakened over time, you may want to add a few more ounces of fluid. Now you hear the pump operating (per the video), but there is no movement from the latches?


If you manually close the top, what happens when you try to open it?

 

I have had some time to look at this. I cleaned all the contacts and switches, still had the problem. Decided to recover the headliner and I had visual access to the latch pin mechanism. I uploaded a link to a video and you can see it starts to move to the right then stops an returns to locked position. If I use any tool as leverage I can assist it with a little force and it will continue past that point and open the top latch. I have had to do the opposite last time I closed it yesterday.

IMG_5936_zpsshp1zpwm.mp4 Video by snwbrd63 | Photobucket

 

Was the engine running when you were operating the roof? Often a weak battery could cause this problem. I would also suggest checking to see what fluid is in your system, the old brown/yellow fluid needs to be replaced with a green color synthetic. I see that you are on an old thread that addresses lubricating the latch have you done that? If not you should.

 

Gus, yes the engine was running, and I have the synthetic oil in the system and I cleaned all the switches and contacts. I have some time this evening I am going to
spend on it.

 

Lubricate the latch piston.

 

Tauni_XK8 I just installed Gus's pressure reducing system yesterday after my top wouldn't go up by itself. I've been meaning to do it but the weather has been so bad that I kept putting it off.


Anyway I got a close-up and personal lesson on how the system operates so let me butt in on this thread.

Dennis07 is on the right track so pay attention.


Let me add a couple of the finer points I haven't heard of yet. On the reservoir at the backend of the pump you'll two lines on the outside that indicate the minimum and maximum levels for the fluid. When the top is fully lowered the fluid level should be at the upper line and when the top is fully raised it should be at the lower level. In your video there was a sudden but very slight change near the intake of the pump but there was no discernible lowering of the fluid which should have been going down at least an inch as the fluid was being pumped through the lines to operate all the mechanical parts. Now the system is supposed to be self-bleeding so I can't under why there's so much fluid and so little movement. You did say didn't you that this was a video of you raising the top.


Of course if you were putting the top DOWN the fluid level should have gone UP and it didn't do that either. If you had a leak somewhere under the close to 1600 PSI the pump pushes the fluid with you should have seen a loss of fluid somewhere in a fairly large amount but you haven't reported that either. That leads me to agree with Dennis that the pump is indeed cavitating and not actually moving any fluid. I'm not sure how the impeller is connected inside the pump but it's possible that it's beginning to slip more often then its actually pumping fluid and has now reached the point where it's mostly doing NOTHING. I think at this point with what you've posted your problem is in the pump and not the lines or other mechanical parts.


Perhaps Gus has figured out a way to check the pumps output pressure or volume as a way of checking it's performance.

 

Sorry but the fluid should only fluctuate just a little between the lines. This is a misprint in the manual! The reason for the slight movement is that this system is a push – push so the amount of fluid to open is nearly the same as it is to close the slight difference in the level is dependent on the position of the pistons in the rams. So fill it to the top line in any position of the roof and all should be good.

 

another thing you may try is to manually operate the latch to open then lower the top then lower the latch again then try it in reverse open the latch raise the top and then lower it again may give you a hint as to where the problem is . when my latch started leaking for the second time i blocked of the ports for the latch and operate it now with a
allan head socket on a short extension . wont get the green shower again for sure now .

 

I would be hard pressed to say the pump is captivating the fluid, air compresses hydraulic fluid does not hence the reason for using it. The fluid is being moved and pressure is created by a pump that operates like a rotary engine only it is moving and compressing fluid resulting in it moving the latch / rams. If fluid is missing it is because of a leak or air in the system. I used the term push/push because when the system is in a forward motion the fluid in the rams or latch are going in one hose the fluid in the other hose is exiting back into the tank. Now if you had replaced a hose or a device in the system you will see a loss of fluid and that is because this system will purge the air out of the hoses with the fluid until all the air is gone.

 

The question I have now is, " is it working now"?

 

We're in danger of hijacking Tauni's thread. Tauni, are you out there? Phone home!


RDMinor, I've heard the sound of the pump cavitating but only in the presence of an active leak (poor seal at a hose connection). Quite distinctive it is, and the conv. top would not operate. But in a healthy system ... not leaking, and enough fluid in the reservoir ... I don't think there can be cavitation for more than an instant. System should purge itself. Given the checks Tauni has done, it seems unlikely now that this is his problem.


Reservoir Filling:

I know, I know: beaten to death, much ado about nothing. Maybe, But it could matter if an overfill or underfill is not harmless. And since the topic has come up again here ...

Fluid level change: The change in volume of fluid in the reservoir, top-up v. top-down, exactly cancels that in the rams. This volume change makes for a level change. How much can be worked out from reservoir dimensions, but it's easier to just observe it. The level change is less than the space between reservoir upper & lower lines, but not so small that we can ignore it.

Reservoir filling: The Jaguar spec' as written (JSAW), in abbreviated form is ... lower line, top up / upper line, top down. We can all decide for ourselves whether we think this is correct or a documentation error. I conclude that it's correct because...
- Writing JSAW required a lot more work than just writing "between the lines". An improbable error.
- JSAW shows up multiple times, in multiple docs, spanning multiple years. Sometimes with a "Caution" heading. If it's an error, it's a tenacious one.
- Every other Marque I've looked at says something like JSAW ... fill to this spot with the top in this position. None say fill the reservoir the same way whether the top is up or down.
- JSAW is the only way to guarantee no over-fill or under-fill.
If your conclusion about this is different than mine, that's fine with me.

So who cares? An overfill could occur if instead of JSAW we fill near the upper line with top top up, because it will go even higher with top down. I'll say something about possible down-side of an overfill if there's interest.

 

[QUOTE=Gus;1144673]I would be hard pressed to say the pump is captivating the fluid, air compresses hydraulic fluid does not hence the reason for using it.




I would also be hard pressed to say that the pump is CAPTIVATING the fluid<G> I'm happy to see someone else whose fingers type one thing while their brain is thinking an other<G><G>

While it's true that fluids can't be compressed and air can be it's also true that all fluids are subject to CAVITATING under the right circumstances. Especially where air is involved since a cavitating pump is simply the action of forming bubbles of air, or cavitate. Our own blood streams are essential closed fluid system that use pressure to push/pull the blood through the veins. Works pretty well UNTIL air is somehow able to get into the system. This leads to the heart suddenly 'cavitating' and pumping air bubbles instead of blood and most often that leads to an venous air embolism which can quite often be fatal.

How ever the fluid is being pushed through the system be it a rotary pump or some sort of impeller type pump if air is in the system that can lead to cavitation and, if you'll allow, a venous type "air embolism" or blockage of the system.

Since we know that air CAN be compressed then lines with a sufficient amount of air in them will not be able to exert the pressure necessary to raise the top.

I don't know if that's his problem but absent any leaks or a lack of sufficient hydraulic fluid, or a binding of the mechanical pieces I'd have to think the problem resides in the pump somehow. If I'm right then there would have to be some place on the inlet side of the pump that is sucking or did suck in air instead of hydraulic fluid.

Of course that would also be the likely place for a leak to be found so around and round we go<G>