Author Topic: installing new clutch  (Read 3794 times)

johnr

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installing new clutch
« on: September 12, 2006, 09:42:05 AM »
I took my clutch housing to a shop I trust & had a new clutch installed.
I re-bolted it to the trans axle and now am not sure how to adjust the
arm correctly.  It just seems to wiggle back & forth,  and I feel no pressure on the clutch when pressing it back to the servo.  I tried to follow the directions in the manual  ( I have three, Haynes, Clymer & Chilton's) and they all pretty much agree.  Shouldn't I feel some spring pressure as the clutch releases?

Before I bolted the housing to the t-axle I moved the arm around and
the whole thing moved back & forth with it, so I assume the actuating
arm is positioned correctly behind the release bearing.  I also need some help finding a new servo,  when I press the arm back into to servo and seal the vacuum hole, it won't stay down.

I sure would appreciate some advice as I love the car.   Thanks!

bookwus

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installing new clutch
« Reply #1 on: September 12, 2006, 10:45:40 AM »
Hiya John,

I'm having a little bit of trouble visualizing what you are describing.  I think this is just a matter of semantics - so let's do a little defining.  Starting at the clutch servo - the rod that is attached to the clutch servo is the clutch release shaft.  The clutch release shaft is then connected to the clutch operating lever.  

When you use the term clutch arm, are you referring to the clutch operating lever?  If so, have you checked the bolt on its lower connection to the clutch shaft (the internal shaft - not the clutch release shaft already mentioned)?

Servo rebuild kits are available at a number of places online.  You might want to give CIP1 a shot.  These kits usually run around $30 US and basically are just the rubber bladder and a new body clamp for the servo.

I'd be interested in knowing how you found new clutch components.  Did you replace the pressure plate and the disc?  The fact of the matter is that some clutch components are the scarcest of all AS related parts.  Just about impossible to find.

Best of luck to a fellow Oregonian.  And keep on coming back - we need to pool our knowledge.
ike

70 AS Bug

johnr

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auto-clutch
« Reply #2 on: September 12, 2006, 05:41:22 PM »
I'll do my best here.  I am talking about the clutch lever which is attached to the servo.  I turned the clutch shaft in counter-c-wise all the way with out tightening the clutch lever, as instructed in the manual.  I then pushed the servo rod in and adjusted the clutch lever to 30mm distance from it.

It feels like it's just bouncing around in there when I move the clutch lever back & forth.  I should feel the force of the pressure plate pushing the clutch open when I move the lever back towards the servo, shouldn't I

I had the clutch done by 2nd street foreign car repair in Coos Bay.
The boss is a VW owner,  and knowledgable about auto-sticks.
I just took the housing & parts into him.  Thanks!

volkenstein

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To get you started....
« Reply #3 on: September 12, 2006, 05:57:38 PM »
Johnr,
        First off, since you have a new clutch and will be getting a servo bladder the shaft (with LH thread eyelet that is attached to the servo bladder mechanism) should be adjusted to "baseline" specifications.
Your Haynes at least should have this measurement.

If you have taken the long arm (clevis joint at where it connects to the servo shaft, and clamps at the actuating shaft) off, then you will have to re-set the whole relationship in order to get everything working just so.

Unfortunately I can't give you much guidance on resetting the long arm as I haven't ever done this. I'm still monkeying around with my spare trans and trying to make sense of exactly how to set this.

Regards
Volkenstein
1 Super RHD Semi-Auto "Klaus"

68AutoBug

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Hi JohnR and Sean and Mike
« Reply #4 on: September 13, 2006, 01:01:36 AM »

Hi JohnR
I don't think You should have undone the clutch arm....
thats what I did to mine years ago...  
and it took Me ages to get it to work --
what I did..  I took the clutch servo Off..
then I moved the clutch arm as far forward as it could go -
and done up the lock nut/bolt..
Now its just a matter of adjusting the clevis arm that screws into the
clutch servo...
I kept adjusting the clevis adjuster, until I could get the car into reverse
[slowly] without crunching...
I can make it crunch going into reverse by moving the gearlever quickly..
and into Low gear without ever crunching..

and Yes, I could move My clutch arm back and forth and it would hit something but never any tension...
the books only advise You --
if the clutch arm is still located on the shaft - as it left the factory...

sounds like Your Clutch servo bladder has a hole in it...
as mine doesn't move if You block off the hole...

cheers

Lee  -- 68AutoBug -- AUstralia --

http://community.webshots.com/user/vw68autobug
 

ttp://community.webshots.com/user/vw68autobug
--- 68AutoBug  ---  Lee  ---  Australia ---
-- helping keep Air Cooled Volkswagen Automatics on the road -  Around the World --

johnr

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autostick clutch
« Reply #5 on: September 13, 2006, 07:38:02 PM »
Thanks lee,  good advice.  I just finished taking the clutch housing off the axle to see if I had maybe got the clutch shaft in wrong.  Can't see anything wrong!

volkenstein

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Baseline spec's from the Bentley & SP manuals
« Reply #6 on: September 13, 2006, 11:32:24 PM »
Johnr,
        FYI from the manuals.
The setting for the servo shaft is:
Back off the LH thread nut on the eyelet end.

8.5mm from the steel servo plate (on the bladder) to the bottom of the long adjusting nut.

Adjust eyelet until the measurement from the steel servo plate to the centre of the eyelet is 77mm. Do up the nut to lock this measurement.

A good starting point for the arm is when you put the bellhousing back on (and the actuating shaft is engaged between the pressure plate and T-O bearing prongs) the main case, turn the actuating shaft (with the long arm off!) clockwise until you feel resistance. You then know that from there you are at the point just before pressure plate release.  Put the servo/bracket assembly back on, and then put the long arm back on the actuating shaft and go from there!

Regards & HTH
Volkenstein
1 Super RHD Semi-Auto "Klaus"

johnr

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installing new clutch
« Reply #7 on: September 14, 2006, 09:05:04 AM »
tHANK YOU VOLKENSTEIN.

volkenstein

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I screwed up!
« Reply #8 on: September 15, 2006, 05:12:17 AM »
Johnr,
        I went and checked the Bentley & my spare servo.
The 8.5mm should be from the top of the hex portion of the servo stud, to the bottom of the adjustment sleeve (the 40mm piece of hex that the LH eyelet screws into).

The 77mm goes from the top of the hex portion of the stud to the centre of the eyelet.

 :oops:
sorry about that
Volkenstein
1 Super RHD Semi-Auto "Klaus"

johnr

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installing new clutch
« Reply #9 on: September 15, 2006, 10:02:00 AM »
Many thanks once again!

johnr

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Re: Baseline spec's from the Bentley & SP manuals
« Reply #10 on: September 18, 2006, 05:51:16 PM »
Quote from: "volkenstein"
Johnr,
        FYI from the manuals.
The setting for the servo shaft is:
Back off the LH thread nut on the eyelet end.

8.5mm from the steel servo plate (on the bladder) to the bottom of the long adjusting nut.

Adjust eyelet until the measurement from the steel servo plate to the centre of the eyelet is 77mm. Do up the nut to lock this measurement.

A good starting point for the arm is when you put the bellhousing back on (and the actuating shaft is engaged between the pressure plate and T-O bearing prongs) the main case, turn the actuating shaft (with the long arm off!) clockwise until you feel resistance. You then know that from there you are at the point just before pressure plate release.  Put the servo/bracket assembly back on, and then put the long arm back on the actuating shaft and go from there!
*************************************************************

When I have turned the actuating shaft until I feel resistance,  do I put the long arm back on as far back towards the rear of the car as it will go?
So it touches the clutch housing?

Regards & HTH
Volkenstein

volkenstein

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No, try it this way..
« Reply #11 on: September 18, 2006, 06:38:02 PM »
Johnr,

Quote/
When I have turned the actuating shaft until I feel resistance, do I put the long arm back on as far back towards the rear of the car as it will go?
So it touches the clutch housing?
/Quote

No. When you feel resistance this is around the point where your servo arm sit's "at rest".

What I would do as a start is whack the servo assembly back on. Then tweak the actuating shaft till you feel resistance and leave it there. Next is, with the servo arm pushed back as far as you can, measure  say 30mm from the centre of the eyelet and put the long arm on the actuating shaft so it's clevis is directly over this point (the 30mm away point!).
Then move the long arm away from the servo and tighten the clamp.

That'll be a good starting point.

DISCLAIMER! Why 30mm instead of 40? 10mm free play at the supposed "take up" point and because you don't have a "reference point" to start with. AND..despite my reading the Bentley & other manuals I am still unsure of exactly how their method ensures correct engagement.
Something to measure up on the spare trans when I have some time......

Now here's something. The Bentley & My SP manuals give a figure of 40mm as the connection point. You've said 30mm. Odd. Unless the Bentley etc are including say 10mm arm movement freeplay (so the T-O isn't being driven all the time)?

Anyone else got ideas??? Pretty Please?


Volkenstein
1 Super RHD Semi-Auto "Klaus"

johnr

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autostick clutch
« Reply #12 on: September 19, 2006, 08:57:38 AM »
Once again thanks!  The book says the same thing, but not very clearly.
You made it understandable!

volkenstein

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Playing in the shed
« Reply #13 on: November 17, 2006, 04:27:11 AM »
FWIW,
         I worked out that the leverage ratio is roughly 8:1. That is 8mm of movement at the long arm's servo clevis joint centre equates to 1mm of linear movement along the centreline of the T-O bearing.

Bad news is that there is 15mm of long arm feeplay when you attempt to reverse direction.

So I told Johnr 30mm servo movement from where the actuating (gearbox) arm feels resistance. That equates to 3.75 mm of T-O linear movement to actuate the clutch, and a 1.25 mm T-O linear movment of freeplay before the T-O contacts the pressure plate splines, assuming we are all playing by the 40mm setting the manual recommends.

But this still means there is 15mm reverse freeplay of the long arm.

BTW. My long arm/actuating shaft was marked prior to me pulling it off, I just placed it where it originally orientated.

Next up I'll bolt the servo and bellhousing/clutch etc together and fiddle with that and determine how/why all the manuals tell you to start with the long arm touching the bellhousing.

After testing a few more ideas and such I am hoping I can come up with a foolproof method of getting the initial setting spot on the first time.


Volkenstein
1 Super RHD Semi-Auto "Klaus"

johnr

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servo adjustments
« Reply #14 on: November 17, 2006, 09:03:19 AM »
I compromised and set mine at 35mm,  half way between 30 & 40.
Works fine.  I still can't figure out why the damn thing works, but it does!