Upper line, top down ... lower line, top up.

Also ... For Gary Jackson ... another usual suspect is the petcock located on the pump body. Make sure it is completely closed ... i.e. turned clockwise.

 

The upper line is FULL and the lower line is REFILL. This system is closed and is a push push system if that makes sense what goes in on one side must go out on the other so the level is the same. Fill it to the top level run the pump a few times and fill again if necessary.

As for the latch hard to operate this takes place when a seal or “O” ring is dislodged in the latch or the mechanism is in a bind.

Be sure the petcock on the pump is closed clockwise direction when ready to operate the unit electrically.

 

A little reflection tells us that the level of the fluid in the reservoir must be different with the top up than with it down. Reason being that in one case the rams are extended and full of fluid; in the other case, well, they ain't. Fluid volume held in the rams is not constant, so it can't be so in the reservoir either.

The meaning of the two marker lines on the reservoir is clearly spelled out in JTIS under a "caution" heading: lower line, top up; upper line, top down. They put the two lines there for a reason. Of course, one may choose to ignore this.

 

Operate the roof in both directions and see the difference it is minimal. What is pushed in on one direction must exit in the other direction. Fill it to the top line!

 

With mine the level in the reservoir goes up when the top is opened. I believe I also saw a TSB or some other info that indicated the upper line was the level with the top opened and the lower line was the level when closed. I suspect it is the fluid in the rams that gets displaced when the top is opened.

Doug

 

Think about this for a moment, when the top is up or down the latch is stowed in the closed position. When the roof is opened and closed the rams lower or open the roof the same fluid is returned to the tank as it would when it is closed. It might have a slight difference between the two but not at the magnitude of the line separation indicated on the tank.

 

The difference between the two hash marks on the tank corresponds exactly to the amount of fluid which must be pumped from the reservoir into the rams to raise the top.

Nothing is "circulating". It's just like pumping water from one bucket to another. We pump fluid from reservoir to rams ... rams extend as they take in fluid ... top goes up ... less fluid remains in reservoir. Reverse the process, fluid returns from rams to reservoir.

It's no more complicated than that.

 

No Dennis,

Each lift has two hoses one at the top and one at the bottom when you push fluid in on the top to lower the roof the same amount of fluid is returning to the tank and if you think that is incorrect then you tell me where that fluid is going!

 

The "what goes out also goes back in" line of reasoning would be valid if the rams held a fixed volume of fluid. They do not.

It is because they take in and hold fluid that the rams extend in the first place, causing the top to raise.

When this fluid is drawn out of the rams and returned to the reservoir, the rams contract, the top goes down.

Again, it is no more complicated that that.

And of course it's easy to look at the reservoir and see this at work. The missing fluid represented by the level drop from upper to lower hash mark ... it's in the rams.

 

My point the same amount of fluid being pushed in is returning back into the tank making it the same level! At no time does the fluid bypass the piston that pushes the pistons or rams resulting in the same amount returning as being pushed in. The level in the tank is the same in either direction of operation.

 

I'd tend to agree with Gus, whatever volume of fluid is pumped into one side of the ram, you would expect the same to be expelled from the other.

But, this is copied directly from JTIS.

"Two fluid levels are marked on the pump reservoir body. The upper mark denotes the fluid level when the top is fully lowered and the lower mark denotes the level when the top is fully raised."

Who is going to make a video?

 

Norri,

I'm repeating myself but the "same volume being expelled" would be true if the rams held a fixed volume of fluid. They don't. They take in fluid as the top is raised and hold it until the top is lowered. The amount of that held fluid is exactly what causes the level in the reservoir to go down.

I'll let someone else have the last word on this if they wish. But those two hash marks on the reservoir are different because there is fluid held in the rams when the top is up. That's why we are told to fill to one level top up, to a higher level top down.

 

When the fluid is pushed in to raise the roof the fluid in the ram that was used to lower the roof is then put back into the tank. This pump does not run on a vacuum it is a push to open and push to close the fluid not used as pressure goes back into the pump you should have little or no fluctuation in the level.

Norri,
As for the statement in the JTIS I believe the point was missed in the interpretation.

Dennis,
As for the last word – it is not about the last word it is giving correct and accurate information and that is what I am trying to do. You sir can take it any way you want……

 

That's not what the diagrams indicate.
Anyway that is not the question is it, the question is does the fluid level fluctuate as the top moves, I'd don't know, I'd have guessed no but the info from JTIS indicates otherwise.

I don't see any other way to interpret it other than what it says.

So once again who has the camera?

 

Does the fluid level change? Yes, in a perfectly repeatable way. Not just a few drops ... but enough for Jaguar to differentiate between full marks on the reservoir for the top-up and top-down conditions. Raise the top, level goes down; lower the top, level goes back up.

So where does the fluid go ... and then return from? It goes into the rams. After all, that is what makes the rams expand to raise the top.

Sanity check: if this is so, the reservoir fluid level should be lower with the top up ... with fluid stored in the rams. That's in fact what happens.

If I'm following you, you are saying that the presence of hoses on both ends of the ram in the JTIS picture indicates that flow rate out = flow rate in. Honestly, it does not. When the fluid-containing volume inside that ram is changing, (say it's expanding) then by definition flow rate out does NOT equal flow rate in. The excess of flow rate in over flow rate out is what stays in the ram, causing it to expand. Of course we unwind all this when we lower the top.

Where's that fellow that repairs roof latches? He can explain this better than I.

 

I understand what Gus is saying. The cylinders are double action. When you lower the top fluid is being forced into the top of the cylinder and pushes the piston down. I have not looked at the cylinders, but if they have a hose to both the top and bottom that is a reasonable explanation. Otherwise, the pump would have to pull a vacuum to remove the fluid from the cylinder.
RJ________________
97 XK8 85K mi

 

According to the JTIS manual (section 76.86.06--Convertible Hydraulic Pump):

TWO FLUID LEVELS ARE MARKED ON THE PUMP RESERVOIR BODY. THE UPPER MARK DENOTES THE FLUID LEVEL WHEN THE TOP IS FULLY LOWERED AND THE LOWER MARK DENOTES THE LEVEL WHEN THE TOP IS FULLY RAISED.

I guess this should put the discussion to bed (but probably not).

Doug

 

It didn't have any effect in post #11

It wouldn't be the first time Jag literature was wrong, we just need someone to check it out, any volunteers?

Unless the ram has some kind of funky stepped piston arrangement if you put enough fluid in one end to move the ram 1" you will get the same amount out the other end. IMHO.

That's not to say the level in the reservoir doesn't change just that I don't think the cylinder is the cause.

I'm going to move all these posts to a separate thread so as not to hijack Garys

 

OK by me. The key point is that the meaning of the two hash marks not get lost, and how people should refill.

As I see it, as the top raises, fluid disappears from the reservoir and the length of the rams increases. As the top goes down, the rams decrease in length and fluid reappears in the reservoir. It all hangs together.

If there is an alternate explanation for the change in the length of the rams, and the whereabouts of the fluid while it is missing from the reservoir, it would be good to have it explained here.

 

This is what I think the manufacture meant to say or did say and Jaguar put it in the JTIS as "Two fluid levels are marked on the pump reservoir body. The upper mark denotes the fluid level when the top is fully lowered and the lower mark denotes the level when the top is fully raised."

When the roof is in the lowered position the fluid should be at the upper hash mark and when the roof is raised the fluid should not be below the lower hash mark. The fluid being between these two hash marks would enable the roof to operate properly. Should the fluid be outside this parameter it will not. That being said, one would think the fluid level fluctuates between the two hash marks when it is operated and it does but not to that degree. The fluctuation is so insignificant it has no real measurement. I believe the statement was to say do not let your fluid level go outside this area of the hash marks. If your roof were to fail to operate and the roof were open or closed you could look at the hash marks and see if the fluid level was outside the operating perimeter.