Hi All,
Following on from some other work replaced the clutch slave cylinder (short type) and a new kit for the master cylinder, previously sleeved with stainless steel. Managed to bleed the clutch OK. However not sure of the correct adjustment of free-play for the slave cylinder. The manual gives detail for the non-spring type slave cylinder, and only states there should be 3/4" free movement of the clutch pedal…nothing about setting up the slave cylinder.
The throw out bearing was replaced when the engine was removed. Clutch was replaced by a previous owner 10,000 miles ago, and showed no signs of wear, so was not replaced.
At the moment there is about 1.5" of free pedal travel and the is rod on the slave cylinder is shortened to the minimum, increasing the rod length will only increase the pedal free play, if I am reading the manual correctly.
I have read somewhere there should be between 1/16 & 1/8 of free play at the slave cylinder, however cannot find the reference now, maybe it was for another car (MG). Also, when installing the spring, should this be without any tension (or minimal) when at rest, rather than stretched as all this does is push the rod into the cylinder.
Just want to make sure the adjustment is right, not keen on removing the engine to change a throw-out bearing or install a new clutch.
The Series 1 E Type manual (this is the only one on my phone), which should be similar to a MkII, suggests that if a hydrostatic type slave is fitted, as for later cars (with spring type clutch) there should be zero clearance at the rod.
I run 3/16" free play at the slave push rod on both my 62 e type and my 63 MkII - both are the NON hydrostatic type. Both have internal springs and an external spring fitted to the clutch arm. The “acid test” us to remove the cover at the bottom of the bellhousing and make sure that the clutch throw out bearing is comfortably clear of the contact surface.
Hi Russel…with an external spring you want it adjusted so it pulls the piston right down to the bottom of the slave clyinder then adjust the pushrod so you have 1/16inch free play…so your thrust bearing is held off the clutch cover… and only 1/16 inch movement of the pushrod befor the thrust touches the clutch… Steve
I think thats counter to what actually happens, as has been noted there should be only a small amount of travel at the slave cylinder before the clutch yoke is moving the thrust bearing. By having the rod as short as possible that means the yoke is as far from the TO as possible.
If I recall there are two different slave cylinders, a long one and a short one. Not sure which goes with the spring clutch or the diaphragm clutch. If the slave cylinder return spring pulls the piston all the way back that will give sufficient bearing clearance but could that result in over travel of the slave, ie more than necessary to fully release the clutch? Just trying to educate myself. My 3.8S was recently converted from a spring type to a diaphragm type but the shop still used a return spring. Not sure it that is correct but it seems to ensure the release bearing is NOT touching the clutch cover.
Hi John…i dont think it will and your slave has a circlip to limit travel and stop the piston popping out…but when changeing gear typically we dont press the pedal fully to the floor…Jaguar choped and changed slave cylinder length and pushrod length and importantly thrust bearing depth a few times…so you need to ensure you have all 3 correct depending on your clutch cover (spring/diaphragm) to work correctly…Jaguars try at haveing a self adjusting slave (no external spring) didnt work well so they reverted back to an external spring to ensure the thrust bearing is always held off the clutch cover but you do need to adjust the 1/16in…my advice is what ever length slave you have always fit an external spring… Steve
Now adjusted correctly between 1/16 - 1/8 free play. Checked the clutch pedal free travel as per owners manual that came with the car and this is 3/4" as it should be, however will have a look through the inspection hole, to verify as suggested by Paul.
Incidentally I measured the pushrod which is 3 13/16", I did read somewhere push rods were 3 1/2" or 3 7/8"…so maybe the one on the car has worn down 1/16" or this is a 3rd size for the pushrod. According to the parts book, the car should have the first type / size of pushrod, which for the 3.4 ends at engine number KJ 7658.