Re: 1928 multiple disk clutch

Posted by Joe on May 23, 1998 at 19:38:29

In Reply to: Re: 1928 multiple disk clutch
posted by steveg on May 21, 1998 at 21:31:45

: : Hope this helps,
: : Joe
: Joe you seem to know a bunch about these clutches...
: My t/o brg has some wear where the forks hit but the mill marks are still visable.. The plates look good (assembled) with all other indicators Iguess my Tudor has less than 5K miles on it - originalTalk to me, tell me more..
SteveG
Dear SteveG
Don't be fooled by my apparent knowledge of multiple disk clutches.I confess I don't own one myself (although if one should show up at the shop I wouldn't turn it away). But I'm curious enough about this detail of the early "A"s to do some research for both you and myself.
I am fortunate to have most of the published literature on the Model A, possibly excluding some of the latest and greatest.Also, as an appreciator of the Model A I always enjoy researching some of the more obscure technical questions.
Page 223 of the original Service Bulletins includes the service instructions for the multiple plate clutch. (Page 26 of the yellow Dan R. Post reprints)The Victor Page book "The Ford Model A Car" (p. 370) also has most of the information and the same pictures.
The multiple plate clutch differs from the later single plate clutch in that the clutch and it's "pressure plate" components (if I can call it that) instead of being attached to the flywheel are attached to the transmission front shaft and held by a large nut.
On disassembly of the transmission/bellhousing from the flywheel housing, the entire clutch assembly slides out of the splined interior of the flywheel.This interior spline is where most of the dust ends up. (by centrifugal force)
In your case with so few miles on an original clutch, I might try just doing the quick disassemble, cleaning of the flywheel spline, and reassembly.You'll want everything to be dry and clean on reassembly, possibly using some graphite powder lightly in the spline area to keep the sliding friction to a minimum.Don't dust the "disk pack" with graphite for the same reason we don't want any grease in this area.
If on your inspection of the removed disk pack you should see something suspicious such as the dog eared end of one of the friction facings poking out beyond the edge of the disks (indicating a torn or broken friction facing) or copious quantities of grease,you'll probably want to disassemble the disk pack by the methods presented in the Service Bulletins.
Grease in this area can come from the throw out bearing.The grease fitting on the throw out bearing slider not only greases the bearing via an internal channel, but on many of the throw out bearing sliders it also greases the cylindrical surface between the exterior transmission front shaft and the interior of the throw out bearing slider.An overenthusiastic mechanic could potentially contaminate the stack with grease during a routine lubrication session.
You can remove the disk pack by removing the large nut near the pilot bearing of the transmission front shaft.The disk pack should slide off as a unit.
5 bolts hold the elements of the disk pack together.You definitely don't want to undo even one of these without some positive method of restraint on the top and bottom of the disk pack.There is a large compressed spring in the disk pack that would just love to remove your head if you do.Several K.R. Wilson Co. tools were available during the Model A era to service the clutch but I think some ingeniousness could rig up something that would work.A couple of ½ inch steel plates with a 3/4" hole in the center and some 3/4" all thread with nuts placed through the center of the disk pack likely would do the disk pack disassembly as well as the original tools.
On reassembly of the disk pack, you'll want to make sure the exterior teeth of the driving disks of the disk pack are all lined up to match the flywheel spline.A specialized tool was used for this too but I think you could likely "eyeball it" and it'll work fine.You'll know immediately if your lineup is not correct when you can get the disk pack in only so far when returning it to the flywheel. The interior teeth of the driven plates are aligned on the center carrier of the disk pack as you stack them so this is not a problem.
The rearmost driving disk has a sawtooth cut or slot in one of the teeth.This identifies it as the special disk for this location which was held to a tighter manufacturing tolerance than the others.The Service Manual describe the reason for this is that this disk acts as a master plate to maintain alignment of the clutch as a unit relative to the flywheel and thus prevent chattering.
Frankly, I'm envious of you with such a find in an original Model A.In your case I would never consider a change to a single plate clutch.The original clutches were not that common to begin with and an original example such as your I consider more desirable as a result.
As for myself, I have a ‘29 CC pickup (March) which shows a lot of the early "A" features including H style headlight and taillight.But not the multiple disk clutch.Henry used up a lot of his outmoded parts on the commercial line.
I would be curious to know if your "A" has the equalizer shaft assembly on the center brake shaft.Another sign of an early production car.
It's kind of remarkable how Ford took the basic layout of the flywheel and transmission for the multiple disk clutch and adapted it to the single plate clutch with so few changes.With such success too! The Single plate clutches were virtually unchanged for the next 20 years.He must have had some very talented engineers.
Hope this helps.You now have all I "gots".I enjoyed researching your question and got even more appreciation for the Model A as a result.
Best regards,
Joe

Follow Ups:
Re: 1928 multiple disk clutch Steveg May 29, 1998 at 22:02:04(0)

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