I have had similar problems with the gear change.
I was driving over a speed bump when the engine stalled and the oil pressure warning came on. I restarted the engine figuring that it was the jolt from the speed hump which had displaced the oil causing the pressure to drop as the oil levels checked out ok. I drove on for another mile and the warning went off but then I pressed the clutch pedal down and it hit the floor and didn't come back up.
I pulled it out of gear and pulled over to the side of the road to take a look. When I looked under the front of the car I could see hydraulic fluid dripping off the bottom of the gearbox so figured that the hydraulics had failed on the clutch. I towed the car home hoping that this didn't mean that the clutch had jammed causing the hydraulic failure as I didn't feel ready to tackle the mighty clutch replacement job as described on other threads.
I used the clutch replacement guide to figure out how to get to the slave cylinder which is the area where the fluid seemed to be coming from. This involved removing the air filter assembly and battery+ tray. Once removed I could see instantly that the slave cylinder had ejected the piston allowing all the hydraulic fluid to escape (reservoir was empty) To remove the slave cylinder you pull up a clip and pull out the hose which is very stiff so it is probably best to do that before unbolting the slave cylinder. I then unbolted the slave cylinder to take a look. The end of the slave cylinder didn't look right it was slanted like it had been worn down or something had sheared off. So I ordered a replacement and when that arrived I could see that the tip was missing from the slave cylinder.
So I bolted the new one on and prayed that the clutch lever on the gearbox wasn't jammed (it was too stiff for me to push on) It also seems like a very strange design as the rounded end sits in dish shaped end to fork. I would have thought that a better way would be to somehow bolt the end of the slave cylinder to the clutch release fork lever because there would be less play in the system. Maybe somebody can enlighten me on that one.
Anyway once the new slave was bolted in and the hydraulic hose inserted back in it was time to bleed the system. Before I did that I decided to check the master cylinder spring to see if it exhibited any of the problems mentioned on other threads. I disconnected the push rod from the pedal but couldn't figure out how to remove the piston from the chamber. I could see that you had to remove a black collar from the top of the master cylinder and there were two parts to the collar, one half of which could push two tabs through to remove it from the other half but I couldn’t then find a way to remove the collar and I didn't want to resort to brute force. I then had one of them light bulb moments and realised that if I could push the piston down and it pushed itself back out then spring must be doing its job properly which it did. So I decided that no further investigation was necessary on my part (read that as I couldn't be bothered to go back indoors and look up how to do it).
I filled up the reservoir and then put the bleed hose on the bulkhead nipple and opened the nipple. Back into the car to pump the clutch pedal about ten times, out to the engine bay to check, no fluid in the bleed hose, back into the car pump the pedal another ten times. Back to the hose, nothing!. Repeat about 7 or 8 times (the other half not feeling very helpful that day!) and eventually the bleed hose is launched of the end of the nipple and hydraulic fluid sprays everywhere! 10 minutes cleaning up the mess and then I try to refit the bleed hose onto the nipple but it never seems to stay on properly. The nipple seems to be larger than the type you find on brakes and is located in a very difficult position to get to as some other hydraulic lines always seem to get in the way.
I decide to give up on the bulkhead bleed nipple and move onto the slave cylinder figuring that any air will now bleed through the to the slave. To bleed via the slave cylinder you pull up the clip and then pull on the pipe so that it comes out about a cm (sort of half in/half out) this allows the fluid to flow out of the bleed nipple on the top. I bled the system until all the big air bubbles were out but I always seemed to get very tiny bubbles in the fluid which suggests to me that there is air still trapped somewhere.
The clutch now works, but for the first couple of weeks I had to pump the clutch pedal a couple of times before it would go into gear sometimes. It has settled down a bit more now but I suspect that I need to bleed it through better but haven't had the time to do it so far. I may invest in an eezibleed system to try and make life a bit easier. It should be possible to get to the slave cylinder to bleed it without removing the battery but it would be necessary to remove the air filter box
