1999 XK8 with 85,000 miles. I got home one evening after a few more hours driving trying to get one more monitors to become ready, I pressed the top up switch, the top started going up, got half way, slowed right down with the pump straining and ground to a halt.
I lowered it down and tried again, same thing, I lowered it again and this time helped it up by pulling it.
The pump motor was very hot. I went in doors and did some reading.
Maybe I should change the hydraulic oil to Pentosin CHF 11S as recommended, especially as the present oil looked kind of brown. I sucked the old oil out with a Turkey Baster thing, put some new oil in, pumped that back and forth, then sucked that out, then topped up with new oil. Now the top operated as I thought it should.

About 2 weeks later while doing another drive cycle, I pulled into a gas station and noticed that the rear quarter windows were down, and would not raise with the switch. When I started driving again I saw that the "Hood Not Latched", warning was on, I could not lift it by hand so I drove home. I tried the top up top down switch to no avail, pump not running windows not moving.
I tried locking, unlocking with the Allen wrench, no good,
I think it was about now that the door windows started acting up, every time I went near the door handles the windows went down some more, but not go up without using the window switch. More reading, I found out how to get the quarter windows up by removing the relays, and jumping the connectors. I left the relays in the glove box.
This was going to have to be a job for Ron, (Later-Ron), as I had a more pressing problem trying to get it Smogged, and still have, 2 monitors still not ready 14 months and 2,100 miles later.

A few weeks ago I decided I have had as much as I could stand with the Smog problem and I am going to leave that to Ron. Every time I drive the car without current tags I worry about it getting impounded, this is not helping my heart problem. I bought a convertible because I like driving with the top down, as it is right now I cannot drive the car (legally) or drive it with the top down. Being a retired Factory trained Jaguar Mechanic there is no way I am going to take it to a dealer, I recently had a new Aortic Valve fitted in my Heart, and now have more energy and decided to look into the soft top problem.

Some time ago I noticed green fluid in the interior lights. I assumed I had the usual problem of 1 of the top latch hoses leaking, to save time I ordered a hose from Top Hydraulics before I dismantled the car.(very good service) I started by removing the rear seat, and right hand speaker cover. To get the top down, the linkage attached to the hydraulic rams has to be pulled downwards, I could not budge the linkage either side, I tried with the top locked and unlocked which meant I had to crawl in the back and do every thing with the top up. I removed the R/H speaker, it needed to be removed to run the new hose.
It was only when I accidentally released the ram from where it pivots I was able to move the linkage, but I still could not move the left linkage. I removed that speaker, and had to wrap a ratchet tie down around the ram and linkage and put a lot of pressure on it before it suddenly moved, now I could get the top down, (yes the valve on the pump was open all of the time). and have more room to work, and get to the top latch etc. When I removed the top pieces and got to the latch, I could see that both of the hoses were dry, and in very good shape. After a close inspection I noticed that there was fluid at the pee hole, and at the end of the ram, the seals in the ram were leaking.
I called Top Hydraulics, and asked if I could return the unused hose, and send the Latch Cylinder at the same time for repair, I was told yes plus a few extra Bucks. Once again very good service, I got the Cylinder back in a couple of days.
I assembled every thing above the windshield, re-attached the R/H ram, topped up fluid, closed valve, and started engine. I cannot remember exactly what went on but basically pump started top went up to latch slowly, but did not latch, after a few more ups and downs it went up faster but had a lot of trouble latching.
If I let go of switch for a few seconds, then pressed it again it would latch properly. but the quarter windows did not move and no chime.When going down, the top would have trouble getting out of the latch, then with a bang the top would start to go down and then stop dead when it opened 12 or 18 inches with pump stopped. I knew this had to be a switch problem, so I disconnected the plug and socket to the R/H Ram, pressed the switch again and the top went down, but latch stayed up.
I decided to check the switches on the ram, the top switch seemed to work OK when I manually worked the top, but I was not sure about the lower (bottom) switch. with the top up (ram extended) the switch went open circuit, but top down the digital Ohm meter read 1.250 Ohms, quite steady. I wondered if the ram had to go further to go open circuit. I took the ram of the car, it did not matter how far the shaft was in, or whether I slammed it, moved it softly it still read 1.250 Ohms I could not figure this out it should read 0 Ohms. I have attached a drawing of how I think it looks and works. I did not want to damage it in case I had to get it repaired. I looked every where for information on the switches, how they worked? could they be replaced? etc. Nothing.

I decided to undo the nuts and ring terminal, I wriggled and shook the threaded rod, the resistance did not change, the only other thing I could do was to remove the 90 degree elbow, which is opposite the switch to see if I could see inside. Yes, inside is a square brass contact, when the ram is all the way in a spring touches the contact. I saw the contact was covered in a brown substance, I thought it may be left overs from the old fluid. I used a dental pick to scrape the contact surface, and then around the side of it, as I did this the resistance on the meter gradually went down to Zero. I now think it must be rust laying between the bottom of the cylinder and the contact.
I put the ram back on the car and every thing works perfectly, quarter windows door windows, chime, and hood not latched has gone away for first time in a year.
If any one else has problems like mine, check the Black/Red wire from bottom of ram and ground reads 0 Ohms when top down.

Drawing of R/H Soft Top Ram, Bottom Switch Fix on early XK8's

 

What a story. I'm not sure if I would have the patience to go through all that. I would never have thought that rust would be the problem, especially with a Southern California car. I would probably just said "to hell with it" and leave the top down, which I do anyway living in the desert. It would be interesting to try and figure out how the rust formed or how enough moisture was able to get inside the bottom of the cylinder. You should get the "Jag Detective Award of the Year".

 

3 Wires going to Ram switches. Sitting on oil soaked foam under rear seat.
MiragePro, The reason for my patience - Cats, Kids, Vandals, Thieves, Pigeons, and the 2 days of rain we have each year here in San Diego. I live in a Trailer Park, no garage, I will say no more.
I thought hard before I decided to call the brown stuff Rust, but I couldn't think of anything else that looks like Rust particles and conducts electricity. Where could Metal, or possibly discolored Brass particles have come from? Not from the hoses, not from the pump, not from the fittings.
How about the Ram itself? If you look at the pic. I attached you will see a white 3 pin plug and socket, 1 wire comes from the Ram top switch and the other from the bottom switch, the black is ground. this is located under the right side of the rear seat cushion. It is sitting on top of foam insulation which is soaked in a brown oily fluid, also the body work and wiring to the side and below the Ram is oily, and the seat belt is stained. There are plastic ratchet wire ties all over the place, without the excess ends cut off. (not factory)
I think that the right Ram started leaking, it was rebuilt, and upgraded with better seals, (as some re-builders advertise) I assume that involves some machine work, possibly tapping threads etc. and maybe some of the swarf, fillings got left behind? I think the re-built Ram, or both Rams were fitted with new Hoses.