Author Topic: clutch plate dimensions  (Read 10429 times)

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Offline Speedsterautoshift

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clutch plate dimensions
« on: 05 March 2019, 11:23 »
Hi All,
we are having terrible trouble changing a clutch plate. the garage managed to get the old one off, we sent it off to be relined and it came back apparently OK.

Now the garage is tearing its hair out as it cannot get the clutch to disengage.
Does anyone know the actual thickness of the clutch plates, as we have had ones fitted that are 3.2 mm thick and now the garage thinks these may be too thick, as they cannot see what else could be the problem.

The official dimensions for what they supplied are as follows 2 - 180 x 124 x 3,20 s/w if that helps at all.

Please reply if you have any idea of the correct specifications for this as we are desperate!

Regards
John

Offline Raymond73

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Re: clutch plate dimensions
« Reply #1 on: 05 March 2019, 23:19 »
Not sure, but someone might. There is a way to adjust the arm on the canister. You might just need to check the free play.

https://www.thesamba.com/vw/forum/viewtopic.php?p=7569975

There are things to consider if your clutch won't disengage. Your control valve needs power and a good ground (when you touch the shifter). Has that been ruled out? Also, if your transmission has been out (I'm assuming they pulled it), has the ground strap been reinstalled?

Also check out the link below that SB001 posted on TheSamba.

https://www.thesamba.com/vw/forum/viewtopic.php?t=680778

« Last Edit: 05 March 2019, 23:29 by Raymond73 »
'70 AS, 30 PICT-3

Offline Speedsterautoshift

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Re: clutch plate dimensions
« Reply #2 on: 06 March 2019, 10:49 »
Hi Raymond73

Thanks for both links they contain valuable stuff.

I would be happy if someone has a worn but still working clutch as, as we all seem to know now, they don't wear much at all, the dimensions, or even just the thickness of the lining, in inches or in millimeters would be exactly what I need.

However the situation now is that even with the servo disconnected and someone moving the arm with a pry bar as far as possible, the clutch still will not disengage.  The situation is absolutely not to do with the servo, all that is OK and was fine before the clutch was replaced. It has been stripped, checked and adjusted according to the book.  There is also nothing wrong with the rest of the vacuum system, solenoid, tank, pipes etc.

However, I think the spindle connects to the arm by being splined and the pinchbolt could be undone, the arm taken off and then replaced on another spline. I am hoping this is the issue and I am going to the garage in a minute to talk to them about this. The spindle end has a tiny mark on it which is obviously designed to be a reference point.  Even if the clutch is a fraction too thick I feel this might be a way of at least moving it to the point where it can be bedded in.

I spoke to the company that relined the clutch and they were clear that they did not absolutely know what to fit so they fitted what they thought was most likely.  They are willing to skim the plate but obviously each time they do this the gear box has to be taken off and the plate has to be sent 300 miles to them for skimming, huge expense every time in labour at the garage, which is why I am so keen to find out the actual dimension of a new clutch-plate.

I'll let you know how I get on, meanwhile, if anyone has a spare clutch and a caliper, please measure it for me!!!

regards

john

Offline sb001

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Re: clutch plate dimensions
« Reply #3 on: 06 March 2019, 18:51 »
Sorry I have never had my autostick apart to replace the clutch or any components so I can't help you there--

Can you get the car to go into gear with the engine off??

If no then the first thing I would check is the clutch freeplay adjustment on the clutch arm as mentioned earlier... this would also make the most sense to me as the new thicker clutch lining would cause the servo arm limited travel.

There's a guy on here (Rhodrich) who had a similar problem years back and ended up installing a whole new transmission that worked perfectly, he said he would check the old tranny to find out what the problem was, but from what I can tell he never posted about it. Another guy (handofdoom) seemed to think the similar thing you are-- that his clutch had too much padding:

http://vwar.org/forum/index.php?topic=33.msg1930#msg1930

But in his case the problem was solved by adjusting the shift lever contacts.

If you can't even engage gears with the engine off, and it feels like the shift lever is jamming up, the only thing I can think of is something to do with the clutch release bearing- are you (and the shop) sure it was reinstalled correctly? I have read that there's something a little different about the autostick throwout bearing, can't remember what- I found something on the samba that says be sure it's on the outside of the pressure plate, not sure what that means as it has to push against the PP to do its job.

Offline sb001

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Re: clutch plate dimensions
« Reply #4 on: 06 March 2019, 19:02 »
Aaah!
Here's the thread I remembered reading about the clutch throwout bearing-- it goes between the clutch disc and the pressure plate, not on the other side of the pressure plate as with manuals:

http://vwar.org/forum/index.php?topic=2026.msg14827#msg14827



Make sure they have that oriented correctly! If it's wrong it can apparently cause the exact issue you are having.
« Last Edit: 06 March 2019, 21:09 by sb001 »

Offline Speedsterautoshift

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Re: clutch plate dimensions
« Reply #5 on: 07 March 2019, 10:33 »
SB001

you are an absolute treasure!  I will get the garage onto this straight away.
To answer your first question, yes it is possible to get the car into gear with the engine off.  In fact it is possible to start the car in gear, by shorting out the gearbox starter inhibitor switch, and thus drive the car in either reverse, or a forward gear, you just cannot change gear, or engage a gear as the clutch don't work!

I wasn't there when they put it back together but they will be stripping it down again to deal with the issue so I'll speak to them about it and show them this thread.

This may well account for why the mechanic could not simply put the pressure plate up to the clutch and fit the bolts.

Thanks again and I'll stay in touch.
John

Offline Raymond73

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Re: clutch plate dimensions
« Reply #6 on: 08 March 2019, 01:32 »
This may be a shot in the dark, but over in TheSamba they have a tool section.

https://www.thesamba.com/vw/archives/info/tools9.php

Item # 4432 is labeled as a "Clutch gauge for automatic stick shift, 4mm - 6.5mm"



This might function as a simple visual reference to check for maximum or minimum pad thickness?

Raymond
'70 AS, 30 PICT-3

Offline volkenstein

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Re: clutch plate dimensions
« Reply #7 on: 08 March 2019, 09:01 »
Speedman,
                 Sounds nasty, ring your shop and get them to pull off the bell housing ASAP.
The rotten bit of gear is a PULL clutch.

The correct assembly sequence is :
Put new clutch plate onto carrier plate - centre it as well as possible or use a tool/wood stick.
Put T-O bearing on clutch plate - "ears" uppermost
Put pressure plate on
Put all those nasty little screws into the pressure plate.

Torque to 18 ft/Lbs or wrist tighten EVENLY. You may (because of possible alignment issues - choose to leave these little sods JUST done up enough to keep the clutch plate aligned - see below)

Your bellhousing now goes on the trans BUT.......
"ears" on the TO bearing are VERTICAL
Move the clutch arm so it's own "ears" are TOWARD the bellhousing, not the gears.
Now, with more hands than normal humans have - offer up the bellhousing to the trans.
With some jiggery-pokery of the clutch arm, and watching the "ear" pair's engagement...said clutch arm "ears" should now PULL backwards
on the T-O bearing "ears" after mating them.

Now...if the gods have smiled, the bellhousing should engage and go on ALL the WAY. If NOT, I suspect plate-to-trans shaft alignment. Index that trans shaft left or right and try again. After it has slid on correctly - pull off *gently* and check tightness.

I've measured an uncompressed plate - about 7-8mm OVERALL thickness is good.

You may almost be in luck - I've sold my house, and am travelling down to clear the shed (big) of worldly possessions - so I'll have my
A-S trans that I was experimenting with handy.


HTH
Volkenstein
« Last Edit: 08 March 2019, 09:19 by volkenstein »
'71 RHD A-S Super - "Klaus"

Offline Speedsterautoshift

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Re: clutch plate dimensions
« Reply #8 on: 10 March 2019, 17:06 »
Volkenstein, you are a star!

I'll send a copy of this to the garage.

We really are getting to the bottom of this now.

Raymond 73, that gauge is for adjusting the settings on the servo, i.e. 4mm from the mounting plate on the servo to the base of the adjuster, then 6.5mm for the end of the adjuster to the lock nut once wound out.
Wish I had one!

I too scratched my head over the need for the 6.5mm measurement, but then it struck me that, off the car, or disconnected from the arm, the bit that takes the pin could be adjusted independently from the rest of the adjuster, hence the need.

All I need now is to get this to the garage.

Will keep you all posted and thanks hugely Volkenstein for the thickness of the clutch plate, Ill have to see if this is compressed or not as ours is one of the sprung ones.

John

Offline sb001

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Re: clutch plate dimensions
« Reply #9 on: 11 March 2019, 03:47 »
Volkenstein and Lee are the go to guys on here for more in depth autostick issues than vacuum hoses or clutch servos...  ;D that's all I've ever had to deal with on mine!   :P

Offline Speedsterautoshift

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Re: clutch plate dimensions
« Reply #10 on: 11 March 2019, 10:55 »
Volkenstein, I must have had too much wine yesterday, your post said "uncompressed" plate, so my statement about a plate being compressed or not makes little sense.

If it is as low as 7mm uncompressed, then I am in trouble, as the thickness of each piece of friction material is 3.2mm.  So, doubling that gives 6.4 mm, which only allows .6mm for the air gap when uncompressed and the thickness of the metal.  If overall it is 8mm then obviously the air gap plus metal would be 1.6 mm, which still seems thin.

Here's hoping you get time to take the plate out and measure the actual thickness of the lining material, once correctly adjusted, it seems it should not wear hardly at all. So if you can give me that measurement, I can pass it on to the clutch reliners and they can redo the job properly.

If the thickness is OK then it is definitely a reassembly error.

I am dying to find the root cause of all this.

Regards
John

Mine was worn on one side and that was due to incorrect adjustment at the servo.

Offline Tom K.

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Re: clutch plate dimensions
« Reply #11 on: 11 March 2019, 12:33 »
My clutch plate happens to be sitting on my workbench.  The lining on each side measures 2.5mm thick.  The entire plate is 7.0 mm thick.     

Offline Speedsterautoshift

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Re: clutch plate dimensions
« Reply #12 on: 11 March 2019, 15:09 »
God love you Tom K, now I can get it taken off and sent back for relining.

Whoopee!

Offline Speedsterautoshift

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Re: clutch plate dimensions
« Reply #13 on: 11 March 2019, 15:10 »
Too excited, posted too quickly.

Is your plate made up of sprung sections, or is it a single solid plate?  I have seen images of both.

John

Offline Speedsterautoshift

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Re: clutch plate dimensions
« Reply #14 on: 11 March 2019, 15:12 »
yet again, still too excited, if it is a spring clutch, was your measurement of 7mm taken of a section compressed or uncompressed?

regards
John

 

anything