If adjusted to it’s maximum shortness then what would I do to increase free travel? I turned the rod as far as it would go.
The clutch is not slipping as far as I know. Drives and shifts fine. Just engages almost all the way out (close to resting position)
First thing is to make sure you have about a 1/16" of free play down on the clutchfork, then when that is set, go up and see how much headspace you have between the pedal and the master cylinder…
Paul,
Let me fully understand this free play on the rod. My understanding is with the spring off, you should be able to move the rod 1/16 inch into the slave/clutchfork (the freeplay you are talking about). I’m I correct or wrong. And if there is no freeplay on this rod - how would you increase/decrease?
I think I just got it. The free play adjustment here is not adjusting the clutch pedal at all. It is adjusting the free play of the rod. I’ve read the manual many times and I think I just got it. Is that right?
Yes.
But no (if I understand you correctly). You want to be pushing it the other way.
I check it with the spring in place. I just push the eye of the arm forward and see if I get about a 1/16" of movement. You have to overcome the force of the spring to do this but that’s not too hard to do.
Ok - Move it away from the slave cylinder and it should move 1/16 inch. I think very slowly on this.
Thanks
The 16th of an inch, more or less, should be between the throwout bearing and the contact plate of the pressure plate itself.
Because of mechanical differences of the clutch fork that may be a bit more than a 16th at the slave cylinder.
Once you have determined that amount of free pkay, you can then go up and check the headspace.
The clutch fork is connected to the throwout bearing inside the bellhousing. When the end of the clutch fork is pushed by the pushrod, it wants to be set so that you can move the clutch fork 1/16" before it hits a stop - that’s the throwout bearing hitting the pressure plate. Pushing further operates to disengage the clutch so you can change gear. You can’t do that by hand because the clutch diaphragm springs are extremely strong - you need hydraulic pressure to do it.
The pushrod wants to be pushed back into the slave all of the way and it’s threaded length is extended via the end nut such that when all is connected up, the first 1/16" movement of the pushrod out of the slave is simply taking up the slack between the throwout bearing and pressure plate.
With the clutch fork disconnected from the pushrod, you should be able to wiggle the fork forward and backwards. You want the pushrod pulled back all of the way into the slave cylinder and then adjust the nut on threaded end of the pushrod so that the whole lot when connected together can move 1/16".
You can check that by pulling and pushing the pushrod and comparing against a 1/16" drill bit. If the total in and out movement exceeds that, then you have excessive freeplay between the throwout bearing and pressure plate. Unadjusted, that means you end up taking up that slack by having to press the pedal more and you have a “long pedal”. If the total freeplay is less than 1/16", then there is a smaller gap at the clutch plate/throwout bearing end. That means the throwout bearing may be still be contacting the pressure plate and prematurely wearing the throwout bearing during normal driving.
The little spring external to the slave is there to pull the pushrod back into the slave just that last 1/16" after the big clutch diaphragm spring has thrown the throwout bearing off of the pressure plate when you let go of the pedal and it makes sure the freeplay doesn’t settle at less than 1/16". If that happens, you risk never fully disengaging the clutch plate, i.e. “riding the clutch” and premature throwout bearing and/or clutch plate wear occurs.
Basically, you are keeping the hydraulic part of the system separate from the mechanical end inside the bellhousing by maintaining a 1/16" gap between them at the slave.
kind regards
Marek
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You have a hydrostatic slave cylinder set up to operate like a non hydrostatic cylinder. The HS cyl is probably correct for your car year, thou not set up like yours is. I did a crude drawing to show the differences. Also below is Jaguar’s instructions on setting up the hydrostatic cylinder. Most readers believe that you can operate the HS cyl like a non HS cylinder using the external spring. I feel that you should set it up like Jaguar does. The HS system keeps the release bearing in constant contact with the release ring on the pressure plate leading to slightly increased wear of the RB, and does not use the external spring. Most of us don’t put on enough miles to worry about this. The HS system, once properly adjusted, does not require subsequent adjustment for free play - it is automatically done.
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The OP has a 1970 which should be non hydrostic and should have the spring and should be adjusted to 1/16 inch free play. The 1970 also should be the longer slave.
Tom
If @MichaelB 's profile information is correct, he has a Series 2 car. Jaguar abandoned the so called “Hydrostatic” clutch (self adjusting) configuration with the Series 2 (in fact, somewhat before then). They continued to us a “long” (3-3/4" length) slave cylinder, but with a different push rod, an external return spring, and a recommended periodic manual adjustment of 1/16" free play at the slave cylinder just like the S1 3.8s and early 4.2s. The photo of Michael’s slave cylinder looks correct for a Series 2 - and it should be manually adjusted as I described above. Do NOT adjust it as per the Hydrostatic configuration as you will be sorry…
I appreciate all this, but as the hydrostatic and Ser II cylinders look the same externally (both long cylinders), and he’s having problems adjusting it, is it possible he’s got the hydrostatic one installed?
Jaguar adopted the non hydostatic cylinder at engine no 7E18356 - probably summer of '68
You make a good point. With the age of these cars, and the apparent confusion caused by the sequence of changes in the slave cylinder configuration, anything is possible. If the original poster is unable to set up the free play to 1/16" with the current slave maybe they have the incorrect length push rod fitted, which as Geo has indicated, can be fixed with a suitable length bolt and a hacksaw.
Profile correct! Series II OTS. All good in the neighborhood with mine.
For Steve
Boy can I feel that pain
On a car with a new owner that’s having problems , personally I wouldn’t assume anything is correct until it was verified. I spent years struggling with hack work till I worked my way through it all
Every nut and bolt on the car
You have no idea what has been installed over the years and just because it’s new doesn’t mean it’s right with these one size fits all aftermarket parts
I’m a real fan of rebuild your originals
You know they fit ,Luckily you have these experts to tap
Your sooo lucky
Cheers
I’ve had the hydrostatic cylinder on my car since I’ve owned it, 25 years, one clutch, no problems. Just set it right.
Thanks for all the help. I had a lack of understanding of the adjustment. Tomorrow I will lift up car and follow the guidelines in above post. As far as the original slave cylinder or not - I’m not going to worry about that now.
And again, Jaguar used the term “hydrostatic” incorrectly, and people continue quote Jaguar’s malapropism. The two designs are “self adjusting” and “manual adjusting” per Lockheed, who designed the system.Yours is manual adjusting. The difference between them amounts to this: spring vs no spring, 3/4" travel vs 1/8" travel. Depending on the actuating rod, you can go from one to the other by adjusting rod length. I think you’ll find it easier if you remove the pin and free up the rod end off the car. If your rod doesn’t give enough adjustment, you can make a new one out of a suitable bold. Once the thread is clean and moving, it should be pretty easy to get whichever adjustment you need.
In earlier years I had BMC cars which had sc’s similar to the so called hydrostatic Jag ones. If I remember correctly they had a light spring inside the sc which always kept light pressure on the tob. In practise wear on the tob was compensated by wear on the clutch plate so adjustment remained more or less constant (until both reached the wear limit simultaneously!). Is the Jag system the same?