Transmission drum

[1925 Touring]

So my car has a broken transmission brake drum and the engine has to come out for it to get replaced. I know you can buy new transmission drums for 4 to $500. I'm not really wanting to spend that type of money right now on the transmission drum. I was hoping I could find an original transmission drum that was in good enough shape to be used. I found a drum and I am wondering what you guys think of the condition.

[speedytinc]

That drum is a variation I have not seen before. It has the bosses that were re-positioned to later take the late steel disk shoes.
I have a NOS wide drum like this. So this drum would have been produced as a replacement during the early wide drum production?
Very interesting variation.
If there are no wear patterns in the shoe bosses, you have a NOS drum. (Cant tell from the picture angle)
If used, it wasnt used much.

To answer your question.
Bead blast the piece. Minimal @ the driven gear spot & polish the shaft, again not where the driven gear fits.
Check a driven gear for a press fit. The drum will need a slight dressing(hopefully) partly to confirm its still running square.
I would try real hard to save the piece. Use or put in the display case as a rare variation.

I put my NOS wide drum aside as a piece to confirm the drum grind finish.(A study piece) A shoe-less wide drum is not preferred anyway.

[JTT3]

Austin really a neat find, if not mistaken this was the drum that was produce mid to late 25, it has the bosses for the removable lugs that protect the bosses like you’d find on a 26-7 brake drum. So I realize you’re trying to do this on the cheap but that drum & the driving plate alignment will be crucial to your engine survival. That involves more than cleaning it up, checking for cracks, polishing and checking if you have clearance within tolerance on the transmission shaft. While it can be done alone you’ll need some help from someone with experience and the right tools. You’ll get plenty of help here from a visual standpoint but nothing like in person help. I’d encourage you to view the tinkering tips videos on YouTube regarding the transmission with young Mr Bender. It may give you some insight on what the task involves moving forward. Plus you’ll note there are over 40 other T Tips that are a real benefit for down the road help. Best John

https://youtu.be/q9Oo1lHBfsM?si=jIjOFix1BMBWnTRS

Here’s a nice drawing from Martin Vowell of that style brake drum. Thanks Martin for making these available. Best John

[J and M Machine]

I would recommend you check the other two drums along with triple gears while you're there as you may be replacing more than just one drum.!

[Mark Chaffin]

That sure looks to be a regular narrow transmission drum with excellent lugs. The late 25' replacement drum would have the slot in the lug to accept the retainer on the back of the clutch shoe.

Clutch Shoe.jpg (23.68 KiB) Viewed 1682 times

[speedytinc]

That sure looks to be a regular narrow transmission drum with excellent lugs. The late 25' replacement drum would have the slot in the lug to accept the retainer on the back of the clutch shoe.

Clutch Shoe.jpg

The regular narrow drum only has 6 legs. Those lugs have the drive plate mounting threaded holes.
This drum has separate cast lugs for the drive plate mount holes & the disk lugs.

[Dan McEachern]

Nice drum for sure, but I'm pretty sure it will need to groove machined in it for the retaining tab in the replaceable shoes. Nice find. Also, I have driven gears in stock with undersize bores that will allow you to salvage brake drums with undersize press fit areas. Just FYI.

[speedytinc]

Nice drum for sure, but I'm pretty sure it will need to groove machined in it for the retaining tab in the replaceable shoes. Nice find. Also, I have driven gears in stock with undersize bores that will allow you to salvage brake drums with undersize press fit areas. Just FYI.

The lugs are of the early non shoe width. To use the replaceable shoes, all the lugs would need to be narrowed & a grove as a shoe retainer added.
The lugs are too nice to narrow. If the lugs had a lot of wear, it would be possible to machine for replaceable shoes on this type of drum, where as, thats not feasible on normal narrow drums.

[Craig Leach]

Hi Austin,
Interesting part you have there. Could be a transition from the early narrow brake to the narrow brake with the lug shoe? How wide is the drive
lug? Will most likely need the later large disc with the flats between the lugs. First I would clean it up. Bead blast or soak in evaporust or similar
solution to remove the rust then determine if it is useable. No cracks, pits, sizes match up to the mating parts & runs true. It looks to have the
step for the early drive plate check that also. You may have a aftermarket ( we think were smarter than Henry part) or a very rare ford part.
Good luck.
Craig.

[Dan McEachern]

Yup- looks like the lugs are full size. Sometimes ya get real lucky.

[1925 Touring]

I got some more pictures. Thank you all for the replies. I am not familiar very well at all with the transmission differences between the years of the Ford cars other than the fact that the 26 and 27s had a larger brake drum. What is the difference with the lugs? This is a drum I found and some of my grandpa's old parts.

[1925 Touring]

[attachment=0]20231114_172125.jpg[/attachment][attachment=1]20231114_172136.jpg[/attachment][attachment=2]20231114_172140.jpg[/attachment][attachment=3]20231114_172154.jpg[/attachment]

[Swinz]

Your drum looks very similar to mine, but mine has the replaceable shoes, i still need to find an earlier type of cover to plate and establish if the hole positions will fit or can be made to fit. When installed in my car a later cover plate was fitted which made the width of the drum too narrow, the brake band always slid rearwards and wouldnt stay on the drum.

[Allan]

Paul, the outer edge of the driven plate forms part of the brake drum surface. It needs to be the same diameter as the brake drum to perform at its best.

That replacement drum may need to be ground to remove that patch of heavy rust. It would be best to index the driven plate to be used, and grind them as an assembled pair.

Hope this helps
Allan from down under.