Series 2 clutch issue

G'day All,

Shane, I have got you thinking about what you are actually trying to achieve by following the Manual's clutch adjustment procedures. Yes you're right, you cannot adjust the pushrod length under load.
So what I do is fully depress the pedal and see where the slave piston skirt is in relation to the circlip, for example say approx. 8mm above the circlip. Then release the pedal and shorten the pushrod say 5mm by screwing the rod into the fork. Fully depress the pedal and check with your Go/No go gauge and make slight adjustments to get the clearance to 3mm(1/8") using the same procedure as above. (Once you have set the pushrod length next time you replace the slave cylinder it doesn't change very much.)
The reason why you have free play in the pedal is to make sure the master cylinder piston is passed the compensation port so there is no residual pressure in the system. The height of the pedal is set to give the slave cylinder piston the right amount of movement to operate the clutch cover plate forks.
Interesting, my parts manual doesn't list a return spring for the slave cylinder?.

G'day Colin,
I don't have any problems with my clutch setup, as per the Manual.
What you are missing here is part of the design of the clutch withdrawal mechanism on the 2a. The withdrawal sleeve bearing is oil lubricated from the gearbox and the outer race slides along the housing. There is no oil seal between the primary pinion bearing and the clutch. An Archimedes Screw is machined in the input shaft to return oil back to the bearing and away from the clutch assembly. The withdrawal sleeve forms part of this process because it is always rotating with the clutch assembly. It was designed that way in the 1960's so that the clutch system is self adjusting for wear on the driven plate as well. I have never had to replace a withdrawal sleeve bearing in my 46 years of ownership!.
The reason why modern clutch withdrawal bearings need to have clearance from the rotating clutch assembly is they are sealed and grease lubricated. They only rotate when the clutch is depressed. They don't last long if they are allowed to rotate with the clutch when driving normally. They have a return spring on the clutch operating lever and a stop to set the clearance away from the clutch.
That's why you don't park a Series 2a with the nose down a steep hill. Oil flows out along the input shaft and into the clutch assembly.

Thank you for listening to my thoughts on the subject. (We haven't mentioned the trailing brake shoes without return springs or adjusters on the 2A brake shoes and how that works. Maybe the same engineers designed the clutch slave system?.)

Chris

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Originally Posted by Busted Syncro

G'day Colin,
I don't have any problems with my clutch setup, as per the Manual.
What you are missing here is part of the design of the clutch withdrawal mechanism on the 2a. The withdrawal sleeve bearing is oil lubricated from the gearbox and the outer race slides along the housing. There is no oil seal between the primary pinion bearing and the clutch. An Archimedes Screw is machined in the input shaft to return oil back to the bearing and away from the clutch assembly. The withdrawal sleeve forms part of this process because it is always rotating with the clutch assembly. It was designed that way in the 1960's so that the clutch system is self adjusting for wear on the driven plate as well. I have never had to replace a withdrawal sleeve bearing in my 46 years of ownership!.
The reason why modern clutch withdrawal bearings need to have clearance from the rotating clutch assembly is they are sealed and grease lubricated. They only rotate when the clutch is depressed. They don't last long if they are allowed to rotate with the clutch when driving normally. They have a return spring on the clutch operating lever and a stop to set the clearance away from the clutch.
That's why you don't park a Series 2a with the nose down a steep hill. Oil flows out along the input shaft and into the clutch assembly.

Thank you for listening to my thoughts on the subject. (We haven't mentioned the trailing brake shoes without return springs or adjusters on the 2A brake shoes and how that works. Maybe the same engineers designed the clutch slave system?.)

Chris

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Chris,
Having two Series II's I understand the clutch release mechanism but there is no need to have the bearing continually revolving.

The point I was making was about removing the spring so that the slave cylinder takes up part of the travel before being operated. The idea of the spring is that you always get full travel of the slave cylinder available to operate the clutch, adjustment needs to be made elsewhere.
Both my Series II's operate perfectly with spring in place and the one I sold a few years back was the same. No need to measure how far the piston is from the circlip because with full piston travel available it's not an issue although I do understand how spring removal would make the system self adjusting.

Trailing brake shoes don't need return springs until you reverse the vehicle, then it might be an issue.

Colin

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Originally Posted by gromit

Hi Paul, the spring is there so that the slave cylinder is fully retracted otherwise you 'lose' part of it's stroke. What you've done is the way I would do the job to retain the full available stroke. Chris, fit the spring and adjust the pushrod and you won't have to do this because you have the full stroke of the slave cylinder available so it won't hit the circlip. With the spring in place if you can't adjust the pushrod to get a small clearance at the clutch then there is something worn or NQR somewhere. Removing the spring is a 'fix' but with other complications. Colin

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The pushrod is already fully extended. This solution would require either adding a couple of centimetres to the pushrod, or mounting the slave under the bracket and still adding a centimetre to the pushrod. That can't be right either can it? And would you adjust the pedal height to that recommended in the manual for a non-hydrostatic or hydrostatic option?

Shane I don’t think there is a right or a wrong way to set this up, as both methods work.
The key to this maybe re lengthening the rod or going without the spring is wear.
there are a lot of wear points from pedal to clutch plate cumulatively they will add up to the 1 or 2 cms you needed to gain
Good thing is you have got the setup working👍

Cheers Paul

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Originally Posted by Shane Scanlan

The pushrod is already fully extended. This solution would require either adding a couple of centimetres to the pushrod, or mounting the slave under the bracket and still adding a centimetre to the pushrod. That can't be right either can it? And would you adjust the pedal height to that recommended in the manual for a non-hydrostatic or hydrostatic option?

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Shane,

Just confirming Paul's point.
There is lost motion somewhere, I don't have this issue with either of my Series II's or the one I previously owned.

Removing the spring is a 'fix' to overcome your problem but as Chris suggested you can end up with the slave cylinder running out of travel, hence the comment about ensuring the piston is 3mm away from the circlip.

Colin

G'day Shane,

All good with the further posts. Yes I agree you have two methods of adjustment without/ with slave spring. Both work as Colin has said his series 11's clutch had no problems with the spring fitted.
It appears neither is going to work for you ATM however, I posted why each adjustment is made and the design methods which will help I think in fault finding what is wrong with the your setup.
Without knowing ATM where the slave cylinder skirt is in relation to the circlip with pedal depressed and the push rod is fully extended already, I feel the problem is as John mentioned the setup of the withdrawal forks on the splined cross shaft in relation to the pins for the connecting tube. (The manual explains how to set this up.)

So how to move forward without removing the gearbox as you also have brake problems as well.

Your suggestion of making a longer pushrod maybe worth a try, once you know where the piston skirt is as a solution and when you have to remove the G/B for other reasons you can adjust the fork position back to where it should be if that is the cause of the problem.
The pushrod is 5/16" UNF x 4.125" long. A longer one can be made out of a bolt with the head removed and the end radiused.
I could take some photo's of my setup of the connecting tube with the clutch out and fully depressed referenced to a datum point if possible to pickup the angles of the pins?. Let me know.

Chris

Here's a similar problem which turned out to be a hardened pin replaced with a bolt causing the lost motion. Also a lengthened operating rod had been made where someone had maybe tried to 'fix' the problem ?!

clutch adjustment woes

It seems pins replaced with bolts will probably cause problems or the clutch operating arm has been installed one spline out of position.

Another adjustment method.

Clutch Adjustment

If everything is in order there shouldn't be a need to lengthen the pushrod.

Colin

Yes

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Originally Posted by Busted Syncro

G'day Shane,


The pushrod is 5/16" UNF x 4.125" long. A longer one can be made out of a bolt with the head removed and the end radiused.


Chris

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https://uploads.tapatalk-cdn.com/202...83ccd228b0.jpg
Using a bolt is not a good idea. Someone tried that on Sid and it didn’t end well. (It did for me as I got him cheaper)

The bolt has bent by 90degrees.