I installed a 5 speed conversion on my XJS. The car is back together finally, new motor, new everything. It is running pretty good and it is time to put it in gear and back it out of the shop. Oops, can't put it in gear while running, no clutch pedal. It has a new master clutch cylinder and slave cylinder. I bled the system 3 times and ensured the rod from the slave to the fork was securely in place. Still no dice. When cracking the bleed on the slave cylinder with the significant other pumping up and holding the clutch pedal, I don't get a very strong squirt. All components for this build are Jaguar original as I was lucky to find an 80's XJS 6 cylinder stick shift with the Getrag 265 being parted out. So, I think the new master cylinder is defective. I have the old master and ordered a seal kit from Moss. Sadly, most places aren't open right now due to the holidays including Simply Performance that I bought the master cylinder and other conversion items from. The only other thing I can think of is am I using the wrong fluid. I put DOT 4 in it which I believe should work fine. Thoughts?

On another note, the new engine seems to be running rich. I have completed all the checks an reread Kirby's book five times on the subject and adjusted everything accordingly. I initially had an issue with the vacuum line to the ECU and it was running super rich and poorly. After figuring out a vacuum to the ECU issue and the engine running a lot better, I installed clean spark plugs and oxygen sensors and changed the oil as it was thinning out. I also replaced the water temp and air temp sensors with new, but still think it is too rich. Idling at about 700 rpm right now but what is coming out of the tailpie will make your eyes water (new stainless headers/exhaust, no cats yet, no sense in melting new ones until running correctly). I plugged 3 different 80's 16 pin ECU's in and tested, and funny it ran a bit different on each one. The engine might have a total of 30-40 minutes of run time on it, so it might all work itself out once things start breaking in. It crossed my mind I might need to swap out the idle air valve. Also, I have not yet reinstalled the complicated cold start vaccum plumbing yet and am doing diagnosis/adjustments with the engine at temp. I have the vacuum advance hooked to one of the ports on the butterfly with no vaccum at idle right now. Thanks.

 

Hi Randy,

Firstly DoT 4 fluid is fine and is what the workshop manual lists. I refilled my system with this when I replaced slave and master cylinders a couple of years ago. A few thoughts below.

Have you tried pumping the pedal to see if this improves things? If not then you have probably got most of the air out.

Can you see if the clutch lever arm is moving when you look through the observation window in the side of the bellhousing when someone operates the clutch pedal for you?

A final thought; A year ago I had a three piece clutch replacement by a Jaguar specialist. I had already replaced slave & master cylinders earlier but the clutch was now getting noisy and was high mileage. All Jaguar or other good quality parts were used in the replacement. On completion, the mechanic bled the system several times but could not get a good clutch. The pedal was biting about an inch or so up from the floor and you had to ram the pedal right into the carpet to be able to select any gear. Apparently this was occasionally a problem when the cars were newer and somebody in the garage remembered that a modification to the clutch operating rod was sometimes necessary. This comprised bonding one of the old style metal tyre valve caps onto the slave cylinder end of the push rod (the open end of the cap sits nicely over the rounded end of the rod) and thereby lengthening the rod slightly. I was skeptical but it worked a treat and the clutch has been fine ever since. Apologies if this is a red herring but I thought I would pass on just in case.

Cheers and good luck,
LeeP

 

Were you aware that the hydraulic clutch is adjustable? ( assuming your clutch slave cylinder is located inside the center of the Bell housing).
You are supposed to measure the depth of the clutch and then rotate the slave cylinder in or out according to that measurement.
It’s easy to measure the slave cylinder. A straight edge across the open Bell housing, then the trick is to get the measurement for the contact on the pressure plate.
For that part I use the same straight edge but put it on two 2️⃣ identical blocks to measure down to the contact.
Do you understand what I’m trying to explain?