Clutch fork travel - Youtube, check me on this

'66 4.2. Resurfaced flywheel, new disc and pressure plate. PP, disc from reliable source, in their catalog:

“Fits Jaguar XKE 4.2 1965 - 1971, MK2 3.4/3.8 Late *, MK2 340, S-Type 3.4/3.8 Late ** , 420, MKX 4.2, XJ6 1969 - 1978 With Manual Transmission. All 6 Cylinder XK Engines with a 9-1/2"”-241mm clutch fitted. Most 6 Cylinder Jaguar Models from 1964 1978 with a manual Transmission fitted
High Quality Aftermarket Borg & Beck Branded Product. 9.5Inch, 3 Piece Clutch Kit. 1 Set per car.
9-1/2" inch kit with a diaphragm operated pressure plate. This 3 piece kit contains the pressure plate, Clutch Disc and Release Bearing (with clips) This is a direct replacement for the stock fitted 9.5 Inch clutch."

I don’t mind a little free space, but this much free movement seems excessive. Would you mind having a look before I install the engine in the car?

Thanks.

Youtube, 16 seconds (mercifully short)

If that is the Hydrostatic Slave (which I think it is) then isn’t the spec ¾" of free-play? Are you unable to adjust it to that?

I may never know why but for my new clutch (S2, the other type of slave, has an external spring) I had to make a longer than original rod to be able to adjust it to spec. A different system I realize, just mentioning what it took for mine.

That is perfectly normal, and, as the clutch wears, the freeplay will reduce, and eventually be eliminated if you don’t do periodic adjustments (every 25000 miles recommended).

What’s important is the travel BEYOND the freeplay, which is actually compressing the pressure plate springs to release the clutch. You need to adjust the pushrod length to reduce the freeplay to ~1/16-1/8" to get proper pedal travel.

Regards,
Ray L.

OK, thanks. It just looks like it won’t go much further, enough to release the disc. The first thought is, wrong PP from Bangladesh - damn.

I should have measured from deck to bearing and compared to the old one. Forgot this time.

I just installed a new clutch in a friends E-Type a few days ago, and it looked exactly like your photo. Normal travel at the pushrod is about 3/4", and as the clutch wears, the arm moves FORWARD, increasing the space behind the fork.

What I always STRONGLY recommend is, as soon as the engine is back in position, BEFORE anything else is connected, including the motor mounts, install and bleed the clutch slave, adjust the pushrod, and make sure the clutch releases properly, by ensuring you can easily spin the gearbox output shaft with the transmission in gear, and the pedal to the floor. THEN go ahead and re-attach/re-install everything else.

Regards,
Ray L.

There dosn’t seem to be a lot more travel left to actually dis-engage the PP, can you get a lever in there and manually disengage the PP before installing the unit in the car?

Micnell you need a release carbon with a deeper offset, there is not enough space remaining
twixt the release lever and the bellhousing.for correct clutch clearance.
Peter B.

I think the fork would move rearward as the disc wears and the diaphragm moves to the rear.

That’s what I was thinking.

And if you think some more about the geometry of the disk, pressure plate and fork, you’d realize the outer end of the fork moves FORWARD as the disc wears. Consider this - WHY is it necessary to periodically adjust the pushrod, and in what direction does it ALWAYS needs to be adjusted (longer or shorter)? The answer is it ALWAYS needs to be adjusted shorter, because the free-play disappears as the clutch disc wears. IF you don’t adjust it to compensate for this wear, the free-play eventually goes away completely, leaving the release bearing ALWAYS in contact with the pressure plate, resulting in rapid wear, and eventual failure, of the release bearing,

Regards,
Ray L.

This is one area where the wear of the carbon release bearing actually comes to your aid. Any wear in the release bearing actually compensates to some extent for the wear in the driven plate, so you don’t have to adjust the clutch as often as you would have to if the carbon didn’t wear.

Yes, to some extent. But, under normal conditions, the disc wears faster, and free-play gradually disappears. Unless, of course, you DON’T periodically adjust the free-play, in which case the bearing wears very quickly, adding free-play, and you can eventually end up with the fork moving far enough rearward that you can no longer get enough travel to release the clutch (if the bearing does not die from heat-related failure first).

Regards,
Ray L.

Agreed. I guess that if you ride the clutch at stop lights just the right amount, and thereby wear the release bearing at exactly the same rate as the driven plate, you never need to adjust the free play! Of course, you have to remove the engine to replace the release bearing every few thousand miles, instead of spending five minutes adjusting the free play, so probably not a good idea…:grinning:

Per the video, not seeing a spring, it appears this one is a hydrostatic slave cylinder. So unless changed, it never needs adjusted after the initial install.
Tom

But it WILL prematurely wear the release bearing, which is why Jaguar stopped using them…

Regards,
Ray L.

Here’s the bearing I removed.

It’s brand new. …Spring or no spring?

I would NEVER install the internal spring. Hydrostatic or not, use the external return spring, and do periodic adjustments.

Regards,
Ray L.

Which shows exactly why you do NOT want the internal spring.

Regards,
Ray L.

How many miles would you say was put on the car for this amount of wear.I just changed my slave cylinder and
this is how I made the adjustment. I checked my TOB and it looks good.
Benny