Decided to start a new thread, just to clear up any confusion....

I called Lang's this morning and talked to Steve, who has rebuilt a number of T transmissions. I asked WHERE that "special" spacing washer goes and WHY a "two hole" clutch disc drum would not work if using that washer.

First of all the special washer goes against the brake drum hub, taking up the space vacated by the removal of the top hat bushing. Then two of the regular steel washers are placed under the clutch disc drum, as per normal in the later transmissions.

Okay, I understand that...but why can't you use the older "two hole" clutch disc drum, instead of changing to the later one? Well, it seems that Ford changed the location of the clutch disc drum SET SCREW when they went to the three washers under the drum. In order to use the old style drum, you place two washers under the drum and then check your clearances (.015"-.022"), adding or replacing washers as necessary. Of course, this procedure is NOT in the Ford Service book due to it being printed long after the top hat bushing was discontinued.

So the whole point is to end up with even spacing between the drums, along with the correct clearances. Makes perfect sense.

And THAT'S the word.....straight from the horses mouth!

I understand the two hole clutch drum IS the later one - the "early" one has the six holes.

You're right Steve.....I just discovered my error. In any case the later clutch drum can't be used. When I mentioned the combination I had to Steve, he said that someone had been in there before, mixing and matching parts.

At this point I'm seriously thinking about ordering a piece of cored bronze and making a new top hat bushing, just avoid all the fuss. Are there any factory drawings available that show the dimensions of that bushing? All I really need is the thickness of the "top hat" portion...the rest should be easy to machine.

Cancel all that.......I've already ordered a new brake drum which should work with the normal three washer set up.

Whew!

George- your clutch hub will not be compatible with the new drum and 3 steel thrust washers- its not a case of how many puller holes are in the clutch hub- I have examples of both late and early hubs with two holes.

I've posted the following before and posting it again here for reference:

Be aware that the pre 1920 clutch drums are different from the later ones. On pre 1920 clutch drums the distance from the set screw hole to the thrust surface is longer that the later clutch hubs to account for the difference in the top hat thrust washer VS the 3 steel washers. The later clutch hubs will have a ford script on the center area on the set screw side of the clutch hub. The pre 1920 clutch hubs have either no ford script or a ford script on the thrust side of the clutch hub. Using the incorrect combination of thrust bearings and clutch hubs can result in both too much end play and also not enough end play. According to Trent Boggess, the only place this was published by Ford was in one of the 1920 Service Bulletins- I believe the May 1920 one, but not exactly sure. You can search the forum archives for Trent's posting on this

I found it Dan and it cleared up a couple of things for me.....thanks!

Somewhere around here, I have a NOS "top hat" brake drum bushing - I'll attempt to locate it for future reference !

And all that's right but when a mix match of parts is all you have got to work with, then, I've turned the bush off the thrust to use, turned down hubs and faced the thrust face in brake drums all to get the right clearance. Nothing is impossible!!

The spacing of the three drums isn’t controlled by changing
the mix of thrust washers. The washers purely set the
end float of the three drums between the main shaft bottom end and the thrust face of the locked clutch hub also on the main shaft. You can also buy a .015 steel washer and I ended up using 3 x standard thrusts plus a .015”. Although the set up was a bit tight with these 4 a very light skim of the clutch hub
increased the end float to .018” Alan

Forgive me, but I've not heard of a top hat bushing! Please explain, and give a Ford part number.

Larry, I don't have the part number (obsolete anyhow) but it was a flanged bushing installed in the brake drum. The flange provided a wear surface against the clutch hub, along with a couple of spacer washers (hardened steel). Ford changed the design around 1919, eliminating the flanged washer and using three hardened steel washers instead. In addition, Ford changed the location of the clutch hub set screw hole making a rebuild somewhat of a challenge.

In reality, you only need to have a stack of spacers that will add up to .110" from what I understand and that will give you .015"-.027" clearance under the clutch hub.

Larry, the part number is 3320B. Here's one of the ones I got last summer, when you and I went through all that NOS stuff:

Thanks for posting the photo RV - saved me some digging !!!

Further to my earlier post where I incorrectly quoted .015”
shim I used. It was actually .025” Part # 3320BW (steel)
plus 3 standard sized shims to correct the excessive end float
Alan

I now know why I was confused! It pays to call parts by their correct name. I have a NOS sleeve bushing that I've had for years, and as I recall they were used through 1916.