C: Clutch Refreshing Vincent Twin Clutch seals and pieces

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
Try 747 page 12. I'm lifting that information from the book without going back and checking. The mod is simpler than any of the others and can be done with the use of hand tools if machine tools are not available. The first time I did this, which is probably over 60 years ago, I did it by hand using a small grinding stone in a hand drill. This made a 'vee' in the inside of the tube to take the 'O' ring. Nowadays one would use a lathe, milling machine or whatever. Note that the 'O' ring only needs 10 to 15 thou nip to make it completely oil tight.
here it is
 

Attachments

  • mph 747 001.pdf
    417.3 KB · Views: 68

Robert Watson

Well Known and Active Forum User
VOC Member
We have in the past made PD21 from (I think 4140) steel, cut an oring groove internally and then hardened and finish ground them. A nice function-able piece. I have also ground a small bevel on the inside of a PD 21 at the internal bore and put a small oring in there that gets squeezed between the bevel and the inner radius of the bearing.
 

craig

Well Known and Active Forum User
VOC Member
I am in need of an explanation, or better yet a picture or drawing, of the seal provided for series D C20 clutch nut. I received a new C20/1 that is pretty close to my collection of old used C20 laying around from the past. I was expecting a recess in the new C20/1 for an oring.
When I look at the drawing of 1954 C3/C20 pieces, it appears there is a recess in C20/1, yet compared to my new C20/1 with no recess????
What is up please?
ClutchDetailsC3aa2.jpg
 

greg brillus

Well Known and Active Forum User
VOC Member
The flat face of the C20 nut shown buts nicely up against the flat face of the C3 carrier. I use a small amount of grey Threebond on the inner face of the C20 nut, on final assembly do the nut up by hand, then tighten fully with a socket bar or rattle gun to a good 60 Ft/lB'S until one of the three slots in the mainshaft aligns with a slot in the C20 nut. Never had one leak, never used "O" rings or the modified Dowty seals in there unless it was set up that way to obtain the right distance for some end float, no less than 10 thou........Use a tiny amount of antiseize on the C5/1 clutch shoe drive pins as these can stick. And a very small wipe of oil in the bushes on the plate carrier, wipe away any excess or else it will end up on the shoe linings...........Don't make any of the parts/fits too tight as this will make the clutch stick in action............Good luck.
 

Peter Holmes

Well Known and Active Forum User
VOC Member
The flat face of the C20 nut shown buts nicely up against the flat face of the C3 carrier. I use a small amount of grey Threebond on the inner face of the C20 nut, on final assembly do the nut up by hand, then tighten fully with a socket bar or rattle gun to a good 60 Ft/lB'S until one of the three slots in the mainshaft aligns with a slot in the C20 nut. Never had one leak, never used "O" rings or the modified Dowty seals in there unless it was set up that way to obtain the right distance for some end float, no less than 10 thou........Use a tiny amount of antiseize on the C5/1 clutch shoe drive pins as these can stick. And a very small wipe of oil in the bushes on the plate carrier, wipe away any excess or else it will end up on the shoe linings...........Don't make any of the parts/fits too tight as this will make the clutch stick in action............Good luck.
I don't think that you are correct Gregg, if you are using the standard parts for the B+C clutches, and you do as you suggest you will lock the clutch centre up solid, the only thing that governs the desired operational length of the C20 nut is the metal outer ring of the Dowty seal C18/1, if that seal, or a derivative of that seal, such as Maughan and Sons supply is not used then the C20 nut will tighten onto the C17 bush fitted to the clutch shoe carrier C13 before it bottoms out into the C18/1 seal recess in the C3 clutch shoe carrier , and you will not get anyway near the 10 thou end float that is desirable, perhaps this method works just fine on the later D type set up, but I would not want to comment on that as I have no experience with the D s.
 

greg brillus

Well Known and Active Forum User
VOC Member
Notice how I said, unless it has one of the dowty type spacers, I will refit what came out to retain the correct distance for the nut verses C 17 bush clearance plus a shim as necessary. The point was to prevent an oil leak from this area, and that is generally how I do it, nothing special but it seems to work.
 
Top