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Clutch Shaft / Nut / Seal Assembly


Forum Website User
Non-VOC Member
G3 Clutch Shaft
C20 Clutch Retaining Nut
C19 Clutch Thrust Washer
C17 Clutch Plate Carrier Bush
C13 Clutch Shoe Carrier

First of all I need to identify my G3 Clutch Shaft and C20 Clutch Shaft Nut. Is the earlier or later pattern

The Clutch shaft looks like the one in MO16, I know there was a change but I
do not know how to recognize the difference.

The Clutch Retaining Nut has a counter bore on the end that mates with the
Clutch shaft that is about 1/4 inch deep with a taper to the threads.

Are they compatible with each other, if not what does the nut have to look
like to be compatible with the shaft, and which seal will it take, the
o-ring or the dowty. Are there any images on line that show the

Upon assembly with no Thrust Washers, I find there is no end float and my
Clutch Shoe Carrier is locked up. The way I see it, when the Clutch
Retaining Nut is fully tightened it sandwiches the C17 Clutch Plate Carrier
Bush between the base of the nut and the Clutch Shaft. If the body if the
nut is longer than the bush then end float will result that can be minimized
with the thrust washers. I read that the earlier type that used that dowty
seal can use in place a copper washer. I see an opportunity to add a washer
with OD and ID equal to the end face of my nut, making the nut effectively
longer. This will restore my end float. What was the thickness of the
Dowty seal?

Am I on the right track?

Richard Friedman


Well Known and Active Forum Website User
VOC Member
Clutch seal

Hello, Just came across this, I was just about to ask the same question.
My solo clutch has a recess in the carrier that takes a C18/1 seal, the seal that came out was .081 thick, I did not measure the one I fitted, but had to fit a shim under the nut to take up excesses end float. This suggests that the replacement was thicker. The seals that I have just bought are .047 thick which is correct?
Also I am a little confused as to how to identify which shaft, carrier, and nut is which. After 44 years of ownership I really should know, but the two clutches I run have been good to me most of the time. Up to recently The only sealing in either clutch has been Hylomar or silicone on the splines. John.


Well Known and Active Forum Website User
VOC Member
Clutch seal

Hello Richard, To attempt to answer your question, having looked at all the usual sources I looked in Paul Richardson excellent book. The difference between G3AS and G3/1AS appears to be that the later one has a small plain spigot between the thread and the spline. This is I think for the 'O'ring to sit on. The clutch carrier C13 has a recess for the C18/1 bonded seal, the later C13/1 has no recess.
The earlier nut C20 has a flat face to match the C18/1 seal. the C20/1 later nut has a counter bore for the 'O'ring..
You need to have all the earlier or all the later according to Know thy beast (another excellent and essential book), except you can adapt the G3 shaft by making a small sleeve Page 118.
I am not sure of the C18/1 thickness perhaps someone else will come up with that info. John.

Vic Youel

Well Known and Active Forum Website User
Non-VOC Member
C18/1 Thickness

Over the years I have purchased several of these from Conway/Vintech/VOCS and the thickness varies considerably...... so add one or even two and adjust the shim on C20 to give 10 thou float.

I found the best solution was to get a washer machined up to fit use hylemar/silicon.

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