My new to me project XK8 popped a ram hose within a few days of me picking it up. Looked over the hoses and realized the latch hoses had been replaced - had a date of '06 on them. Big relief. Ram hoses were properly decayed and shot. Need to swap rear speakers and fix a rear window regulator so figured I would roll swapping the hoses into the same batch of jobs.

Looked at online options for replacements and decided to try a local hose repair shop first. Paid $138 and it took about 5 minutes for the tech to make the hoses. He made them with the smallest hoses he had available and used the appropriate metric fittings.

Installed this evening and ran the pump a few times to clear out the air. Seems like the rams cleared out relatively easily with the top running up and down well after a few cycles. Haven't gotten the latch to fully close as yet though. Seeing it try but not really apply proper pressure to draw the edge of the top down fully. I didn't swap the latch hoses so don't expect hoses are my problem - could be though...

Hoping the hoses still have some air in them and that my problem isn't a result of my budget hose experience. Anything I need to do to properly clear the lines? I noticed the fluid pushing it's way back into the reservoir is full of bubbles, so I might just need to let it settle for a while... Thoughts?

 

Is a sticking solenoid to the latch lines a thing?

Did some reading last night and discovered the micro switch in the right side ram could have been causing problems. Checked it for continuity and it seemed to be indicating fine when the ram is fully extended.

Realized the latch solenoid is releasing but not until like a minute or so after I've stopped pressing the "raise roof" button. I hear a pop which is apparently opening up the solenoid which then lets me close the latch manually with the allen key.

Shot a couple of videos. Will upload shortly.

 

Here's my switch confirming it works.

 

And my pump cycling. I stop pressing the button at :32 and the solenoid releases at 1:33. You can see some pretty turbulent fluid being pushed into the reservoir at that point. I manually closed the latch with the allen key (confirming the solenoid was open) then pressed the button to to lower the top. No issues there with the latch properly retracting at the end of the cycle.

Also of note, when I inititially start to raise the top, the latch pops up to receive it. So everything is working as it should other than the latch drawing the top down at the end. Finally, even after that "pop," I've tried to operate the pump to complete the closing cycle but am not seeing the latch close.

 

Looks like you need to add hydraulic fluid to the top embossed line and operate it a few times.

Gus
www.jagrepair.com

 

I think it is filled to the top line, but there is very little fluid used in moving the latch, so it may just be a need to cycle more.

 

cdre,

At about the 30 sec. point in your pump cycle video, there is a big injection of air into the reservoir and a corresponding change in the pump sound. This is not normal. If it does not get better after several cycles, a less-than-perfect seal at one of the hose connections (or a bad fitting) is likely.

Feel around the hose connections for any presence of fluid.

Did your hose maker give you a spec on the fittings used?

 

That 30 second point was when the rams were fully extended and the point at which the latch should have seen a load.

Didn't get a spec on the fittings. Checked all of my fittings and didn't see or feel any fluid. Only fittings not accessible are the two at the latch but not seeing any leakage there.

I'll double check the fluid level and cycle it a few more times.

 

You can have either air(keep cycling ) or you have gelled fluid in the latch and end of those lines. Take the latch and lines out then run pump with lines in a bucket and manually move the latch ram in and out with the lines off to purge gelled fluid

 

Pulled the lines at the latch and flushed them into a jug. Clean green - no issues there. Cycled the latch manually without issue. No undue resistance - just that of the seals. Hooked back up and cycled a few times but got the same failure to latch.

Then I realized my top will float down if stopped mid-way. Should I expect that or is it an indicator that my rams are in need of new seals? Possible bad seals on rams could be causing my latch to not operate?

 

Just a thought - you have double checked that the ram hoses are connected to the correct ports on the pump?

 

Comments and questions:

- the rapid leakdown shown in your video is not normal.

- the latch and ram hydraulic circuits are not so isolated from each other as is sometimes thought, so no components can be ruled out at this point (but I suspect the ram circuits).

- it's possible for a seal to be permeable to air (especially in vacuum condition) but not to hydraulic fluid. Or at least only very slightly to fluid.

- please re-check the ram hose fittings for any ... even just a trace ... presence of fluid.

- did the top operate and latch correctly before the ram hose failed?

- the petcock is fully closed, right?

- can you post a close-up of the interior of one of the fittings on the new ram hoses?

 

Thanks for the comments/questions Dennis.

I bought the car with the top not latching. I cycled it up and down a few times manually latching (and opening the petcock) and realized it was low on fluid. Topped it off and blew out one of the ram lines immediately thereafter.

Operating with the petcock fully closed. The latch lines are definitely correct. Never removed them from the pump and those at the latch are staggered. I marked the ram lines when I pulled them and replaced them accordingly. If one or more of the four were wrong I'd imagine I would have all kinds of issues with basic raising and lowering (which I don't think I have).

The tech that made the lines told me that 2 of the 8 fittings he used didn't have o rings but that I would get a metal to metal seal. Now that you mention it, I wonder if I'm sucking in air with a vacuum on the side of the ram not being actuated and that is causing the top switch on the right side ram to not actuate correctly. That would probably result in the leak down and bubbles I'm seeing in the reservoir.

I'll check my fittings tonight and plan to have they hydraulic shop order and replace the two without O-rings on Monday.

That said, possible/advisable to use a jumper to short the top ram switch to direct fluid to the latch and confirm I've got good pressure/operation? Those hoses look like typical replacements for the originals (with '06 mfg markings).

 

Oh now you mention the latch never latched!! I thought you had just replaced leaking lines. There are microswitches that tell send a signal to operate the pump solenoid to pressurize the latch with fluid and then close the latch. You probobly have a back switch in the ram which means a new ram. Consult wiring diagram for info on which ram. Been to long to remember everything

 

Take a look at post #3. I tested the continuity of the top ram switch while operating the top. Advisable to further test by "jumping" the switch on the connector?

 

Those two fittings w/o o-rings sound like the prime suspect to me.

Both on the same hose? Can you substitute hose(s) from the old set that did not fail for the new one(s) not having o-rings and see if it makes a difference?

 

So it looks like I have either a solenoid or a sensor logic problem. I disconnected the blue connected lead from the inboard most solenoid and the roof closes perfectly at that point. The latch properly pulls down. Wondering if maybe I have a bad ground or something preventing the logic from actuated the solenoid properly. Has anyone seen anything like this previously? Is a bad solenoid fairly common?

 

Confirmed the solenoids are good. Swapped them and had the same symptoms. I think the inboard most solenoid is stuck in the open position as a result of either a sensor or something else. Which of the switches should I be checking. I noticed there are some switches in the latch mechanism. Do any of those contribute to the logic that opens and closes the solenoids?

 

Next plan on checking the "top ready to latch" switch. Assuming it's one of those in the header. Probably Monday before I can get back after it...

 

Did some searches and rand across a few references which should will guide my next efforts. Hadn't previously seen Gus's header adjustment writeup - JagRepair.com - A Jaguar Repair Information Resource. And another potentially relevant thread - https://www.jaguarforums.com/forum/x...estions-79540/.


Realized that after manually latching the top, the rear windows aren't going up which further tells me the header switches or the BCM could be at fault. Since having the car, I haven't been able to fully run the top with a hose failing as soon as I added fluid to the reservoir.


Going to try a hard reset then check/clean up the micro switches in the header.