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Disc drum question
Posted: Mon Apr 01, 2019 2:47 pm
by RGould1910
Is the disc drum used with the 3 washers different that the one used with the flange bushing? I am working on a 27 and need to replace the disc drum. I have about half a dozen spares and they all look the same, even the one that came out of a 1912 transmission.
Re: Disc drum question
Posted: Mon Apr 01, 2019 7:32 pm
by Dan McEachern
Yes there is a difference. it is not really well documented, but the difference is between the thrust surface and the centerline of the lock screw. I'll check at the shop, but I recall the one without the Ford script is the early version. RV Anderson originally posted this info 3-4 years ago if I recall, quoting a brief entry in a service bulletin from round 1921.
Re: Disc drum question
Posted: Mon Apr 01, 2019 8:57 pm
by Mark Gregush
From what I picked up; that the early one has several holes around it, the later style has just two. (the holes you would use for pulling it)
Re: Disc drum question
Posted: Mon Apr 01, 2019 10:23 pm
by RGould1910
Thanks for the info gentlemen.
Re: Disc drum question
Posted: Tue Apr 02, 2019 10:06 am
by RajoRacer
There are actually 6 holes around the circumference and a spiral oil groove machined/cast into the bottom where it rides against the "top hat" bushing - I dig one out & post a photo.
Re: Disc drum question
Posted: Thu Apr 04, 2019 12:00 am
by Dan McEachern
To clarify this for everyone- I went back and looked up my printed copy of the forum posting that Trent Boggess did on this several years ago.
The clutch hub that was made for use with the top had brake drum bushing can be identified by there being NO ford script on the hub at all or the Ford script will be located on the brake drum (front) side of the clutch hub.
Later clutch hubs made for use with the 3 steel washers have the Ford script on the side opposite the brake drum (rear) or set screw side.
Steve- FYI: I have both styles that only have 1 pair of puller holes 180 degrees apart, so I don't believe the # of puller holes will completely identify the early or late hub.
Trent noted that this info came from a 1920 Ford service bulletin.
Re: Disc drum question
Posted: Thu Apr 04, 2019 2:34 am
by Corey Walker
This one came out of a 1914 transmission. It has no Ford script anywhere, I thought there was a DB but there’s not. The flywheel was marked Dodge Bros. I guess is why I thought that.
Re: Disc drum question
Posted: Thu Apr 04, 2019 12:14 pm
by Dan McEachern
Correction- "top had brake drum bushing" should have been "top HAT brake drum bushing". sorry for any confusion.