Checking out whether Your Control Valve is working - Gears Grinding?

[68autobug]

             

If You cannot get Your car into gear without grinding...  [in emergency situations You can knock the gearshifter into drive 2]

it means the clutch servo isn't working because...  [and the clutch is still engaged]

No vacuum in vacuum tank -  Leaking vacuum tank - leaking vacuum hose - Clutch Servo bladder leaking -
Usually a leaking hose or servo bladder -  Replace all vacuum hoses recommended - New Servo repair kit available in USA -

Control valve not operating - wire to gear shifter broken - or no power to control valve -
TEST the control valve by grounding out One terminal and putting Power to the other terminal..
it doesn't matter which terminal is which... +  or  - or which wire goes onto which terminal.

Clutch servo is working BUT - the adjuster is not adjusted correctly OR the adjuster is not there?
[In this case You should hear the servo working]
This is unlikely unless You haven't tightened the adjuster locknut after adjustment ..



Lee in Australia






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[CarlIseminger]

So would the clutch arm ever need adjustment over time?  Wearing clutch plate?

And I notice that on the one pic, there is a distance marked 30MM.  Is this the "free play" when the clutch is released?  Or is this the distance the clutch arm travels during enactment?

Thanks

[68autobug]

Hi

The clutch doesn't need any adjustment as when its worn out the clutch arm will be hitting the GEARBOX bellhousing.
You will however need to adjust the clutch servo/arm adjuster whenever the gears start to Grind when used..

The problem I had, was I had pulled the arm off My gearboxes , and going by the workshop manuals
which ONLY tell You how to make a small measuring tool to be used when installing a NEW clutch plate..
I tried this for a long long time but couldn't get into gear... so continued to try to find the right "spot"
then, I took two of My manuals to a local Mechanic friend...  and I had been adjusting it the wrong way.
I had been adjusting so that the clutch arm would press on the throw out bearing...
but I needed to PULL against the clutch throw out bearing....  I finally got it into gear next day...  
I found that I needed to take the servo and bracket off... undo the clutch arm bolt... difficult.. Yes...
pull the loose arm to where the servo was and THEN tighten the arm bolt...
Now the lever should go back to where I have shown... approx 30mm....
The clutch plate wears VERY little, as its either IN or OUT.... No Slippage like a normal clutch...
The torque converter does all that... not a lot of difference in thickness of a new or worn clutch plate.

Its Not free play but the distance the arm must move to depress the clutch pressure plate..
You should be able to feel or hear a click when You move the arm... that is the free play
no pressure on the throw out bearing etc....

cheers

LEE in Australia

[68autobug]

I adjusted My control valve today , 1/2 a turn clockwise
and the thumping the clutch servo used to make is no longer there...

the control valve lets the vacuum from the vacuum tank into the clutch servo
when You move the gearlever....
so, You can adjust the length of time the control valve opens to allow the smooth operation of the clutch servo..

I had been thinking maybe, it will be too slow for the clutch to re-engage after changing gears...
but I should have been thinking milliseconds... not seconds...
My car now drives smoother...
and no noise changing gears....  after 5 years of thumping... 

Lee  in Australia

[CarlIseminger]

I have noticed that my manual part of the clutch seems to be slipping a little every now and then.  You step on it and nothing happens.  Just engine revs.  Does this mean that possibly my clutch needs to be replaced?

[68autobug]

Naturally,
it can be Your clutch plate...
but they wear very little.. as they are either IN or OUT...
No slippage normally..
but the pressure plate will eventually loose its tension???
so, it will possibly down to the clutch..
see if You can adjust the clutch servo, so it doesn't slip...

You can adjust Your clutch servo adjuster until it crunches going into Reverse or Low gear
then adjust it little by little until You can get into gear without crunching...
Hopefully this will fix Your problem...

It would be great to know whether Your clutch servo is going into dis-engage..??
but this is impossible to do when driving... lol

cheers

Lee in Australia

[CarlIseminger]

I honestly think that my clutch plate somehow is slipping. 

I am getting frustrated with the symptoms.  I have posted before asking about a possible slipping clutch and everyone keeps telling me to adjust my servo.  It doesn't happen after I shift.  It happens when I step on the gas after sitting at a stoplight, or I forget to downshift into 1 after slowing down and I step on it.  I feel it starting to slip and then there is a jerk and it catches again.  Very similar to my Chevy 350 SS started to do when the clutch started slipping.

So I guess I am going to have to take it for a long drive to the next city that has a decent foreign car shop that will work on my autostick.

[68autobug]

I honestly think that my clutch plate somehow is slipping. 

I am getting frustrated with the symptoms.  I have posted before asking about a possible slipping clutch and everyone keeps telling me to adjust my servo.  It doesn't happen after I shift.  It happens when I step on the gas after sitting at a stoplight, or I forget to downshift into 1 after slowing down and I step on it.  I feel it starting to slip and then there is a jerk and it catches again.  Very similar to my Chevy 350 SS started to do when the clutch started slipping.

So I guess I am going to have to take it for a long drive to the next city that has a decent foreign car shop that will work on my autostick.

Hi Carl,

It may be the control valve...
as if the clutch servo loses vacuum etc it stays engaged... [pedal out in in a manual]

take the small hose off the control valve [or carby end]
and take a drive locally.. not on the highway...lol

and You will see what happens when the control valve isn't working correctly..
when You press the accelerator down..  Normally,
the vacuum caused goes thru the small hose and the control valve is quick to change the servo
and when You change down with no throttle down..
the clutch servo [via the control valve] is supposed to operate slowly..

I would still adjust the clutch servo adjuster until it crunches gears then adjust 1/2 a turn back..
and see if it still happens...  if it doesn't... then maybe the clutch or pressure plate just operated normally
after the clutch servo operated and it just wasn't enough pressure to stop the clutch plate from spinning...

OR You may be correct in that Your clutch plate is worn down too far...

You may have a problem finding someone who can do the job...
of installing a new clutch plate... [You would have to supply the clutch plate as they are not available thru normal channels]
as the clutch plate is INSIDE the gearbox... and the nuts to undo the bell housing to get at the clutch are inside the gearbox
next to the differential... 

its NOT a difficult job... You just need someone who knows about the autostick..

cheers

LEE

[CarlIseminger]

Thanks for the advice Lee.  I will try unhooking the small hose this weekend and see how it operates without the small hose connected. 

I am guessing that the control valve is working correctly because when I am at idle and shift, it engages slowly, almost as shifting into Drive with a normal automatic.  And when driving, if I am giving it gas while changing gears, it "snaps" into gear like it should.  And when downshifting at the light while slowing down, it engages nicely too.

So that is why I am so hesitant to adjust the control valve as it works so nicely now.  I would hate to get it out of sync.

What makes me think that quite possibly it is the clutch slipping is that the car sat for many many years of its life before I started to drive it.  Just about from 1972 until 2009, it was rarely, if ever driven.  And when I first drove the car home, at first I thought it was the brakes sticking (from sitting so long) when I would start out, but now am thinking it was the clutch slipping.

[68autobug]

Hi again Carl

Well, You wouldn't believe it...  lol.. I have had the same problem...
I screwed the control valve in about another 1/2 turn...
and it was excellent .. nice and slow and NO thumping but in DRIVE 1 when accelerating...
the clutch was slipping... !!  so I have adjusted the clutch servo adjuster...
not straight forward as it was close to the ends of the thread...
so, It came off the clutch arm end, so I unscrewed the other end a few turns then screwed it back on..
I got mixed up a few times and turned it the wrong way...lol
so, I have no idea how far I have adjusted it...??
but the thumping has come back... but its cold weather and the engine is revving more when cold..
so, it IS better when the engine warms up and the revs drop to around 900 RPM...

Just thinking... I screwed the control valve IN another 1/4 of a turn... [just remember where the screwdriver slot is] -- or  l 
and its not like it was before... [the clutch started slipping...] ??

but it was the clutch plate slipping.. and the more I revved... the More it slipped..
I was thinking about moving the clutch arm... but undoing the bolt that holds it on was a nightmare last time... lol

[the manuals say {from memory} that when the clutch arm hits the gearbox.. the clutch plate is worn out..]
clutch plates only wear about 2 -3 mm approx.. so it doesn't take long to hit the rivets...

maybe I should have had the clutch plate relined before it went into My car...
although from memory it looked OK...
I have two spare gearboxes so I should pull one apart over winter...
and check it out and pull the release bearing apart and fill with Lithium Moly grease..

I'm just worried that the throw out bearing may have pressure on it all the time... NO freeplay ..
it was hard laying under the car and trying to check the clutch freeplay...
its much easier when the gearbox isn't in the car or the engine is Out... lol

the clutch actually PULLS the pressure plate...
it doesn't PUSH the plate like manual beetles...
the clutch arm pulls the two lugs on the throwout bearing..

cheers

LEE









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