Is it possible to use the replaceable transmission brake drum lug shoe set offered by Lang's to repair the worn lugs on my '24 transmission? Lang's shows them to be for 26-27 models - can they be modified to work in the earlier models? If not, how can I repair the serrated edges of the lugs so that the clutch plates wont bind? Will filing work?
Thanks to all for any info.
Mike in Palmer, Tx.
Filing works if the damage isn't too bad. Care should be taken to try filing about the same on every lug so not all the forces from the large discs goes on the same two tabs.
Machining all the way down to fit 26/27 lug shoes weakens the lugs too much - the fastening screws for the driving plate goes into the lugs on the old brake drums, while the 26/27's has separate lugs for the driving plate screws.
Ford offered a replacement narrow drum with lug shoes in August of '26, but they are difficult to find. Your '24 drum can't be modified, so forget about that. What you can do is find a '26 brake drum, and get a good machinist to turn down the end so it matches your '24 drum. I've done that, and currently have one in one of my cars.
Filing is at best a shade tree fix. Problem is twofold. First its almost impossible to file each lug so the distance between the disc teeth and the lug edge is the same for each lug. This results in uneven contact and grooves in the lugs where the distance is closest. Second you increase the distance between the disc edges and lugs which causes a hammering effect resulting in more grooving. All that being said, its the only way I know of freeing up a binding clutch without changing the drum. The best set up as Larry explains is to use a 26-27 drum and driving plate. The driving lugs are separate from the bolt bosses making for a much sturdier lug, the steel shoes don't wear against the discs like the cast iron lugs and the driving plate is captured inside the drum making for a much more solid connection and eliminating the need for the rear brake drum bushing.
It is very easy to cut down a wide brake drum to work in an early transmission. The only thing to remember is to use the earlier driving plate bolts rather than the stepped bolts you see on the 26-27 set up.
That's why we've made new ones due to the lack of good used ones out there.
A quick note here. If you cut down a '26 drum, and convert it to a narrow drum, you must machine the step on the drum to accommodate the driving plate which is part of the band surface when in use. Do not use a '26 driving plate, however, you will have to oblong some of the screw holes in the driving plate to match it up with the '26 drum. That is mentioned in a late service bulletin somewhere.
You do not have to machine the step. You just remove the the over hang and leave the area over the drive plate and use a 26-27 drive plate. That gives you a full surface for the brake band to use. The replacement brake drum for the early style (1925) transmission with the lug shoes was an odd ball and did use a different drive plate then the early style non shoe type and the later 26-27. When the bolt hole's were moved to the stronger part of the casting the diameter of the circle was moved just a little, I am pretty sure that is what was being talked about in the service bulletins.
I'm not sure it's needed to cut anything to fit a 26/27 brake drum to an earlier pan and hogshead? It's the wider brake band that'll clash with the three dip pans. The drum may go free on at least the later three dips? With a pre 26 hogshead and a narrow brake band, it'll only use the front part of the drum surface, but the lugs with shoes will hold up better than before
Don't know about the wide drum fitting into an earlier pan, Roger. I notice the 26-27 pans had buldge. Perhaps it is there to accommodate the band rather than the band and drum. Got to be a pretty close fit if it works. I wonder if someone has tested it. Even if it does fit, it makes more sense to me to turn it down some both for clearance and because you must use the narrow band. The overhang has no function. When I say turn it down, of course I mean leave enough drum so the driving plate is captured underneath.
Doing a 26 rebuild now that has a 3 dip pan on it and a narrow band on the wide drum, looks like it had been like that for years.
Filing down the worn drum is a very temporary fix. Those lugs are often cracked around the threaded holes in the first place. taking more material from them will only exacerbate the problem. The new drums with the separate lugs as per J&M are the way to go.
Allan from down under.
I will differ with Mark. The step on the brake drum is there for a reason! It is there to perfectly center the driving plate, not to mention the additional strength. Ford put the step in there for a reason, but of course you are free to do whatever you wish.
Richard that bulge came out in 1924, and is commonly called a 4 dip pan. Are you speaking of a different bulge?
The 26-27 drive plate is centered in the brake drum. The outer rim of the drum supports it and centers it. Same as it was before removing the extra lip when installing in a early transmission. You don't remove the whole lip, just enough to bring the edge to the top of the drive plate. No filing and enlarging the mounting holes in the drive plate.
You are thinking of CONVERTING a wide drum to a narrow one and still using the pre 26 drive plate.
Everyone else seems to be suggesting just narrowing a wide drum as needed and using the 26/27 drive plate. Which is a simpler approach.
If a 26 drum is narrowed and the 26 drive plate is used it will be father forward in the engine and will not fully fit in the 4th. main bearing.
I don't think so Art. The 26-7 drive plate bolts up to a land within the drum. It does not bolt up to the back of the drum. Machining some off the back of the drum surface will not alter this internal land. At least, that is how our Canadian cars are.
Allan from down under.
Allan is correct for US made engines too, the 26/27 driving plate is captured by the wider braking surface.
Now I have checked stuff in the garage and I'm more sure no modifications are needed for using a wider brake drum in an earlier engine - if you use the old hogshead with a narrow brake band.
The first picture shows a march 1922 engine with a three dip pan and narrow brake drum. The bosses on the driving plate for the clutch arms goes all the way out to the same outer diameter as the braking surface and the total width from the front of the drum to the rear of the bosses is the same as the 1926 trans shown in the second picture - the bosses were moved in a bit so the driving plate could be captured by the braking surface. So both types of brake drum / driving plate combo needs about the same room in the pan. No need to cut parts that doesn't need modifications.
That's good to know Roger. One problem with trimming the 26-27 drum I encountered was using the older style bolts to secure the driving plate to the drum. Thinking the stepped bolts wouldn't fit in the earlier pan, I opted to use the earlier bolts. The problem using the earlier bolts is there is not enough room to get a socket on the heads making it difficult to tighten them. Now I see you don't have to trim the drum nor substitute bolts.
I have no experience with the stepped bolts. Since my '26 trans is very early, it has the first style screws for the improved driving plate, and they'll fit:
You are correct. The drive plate distances are the same.
Roger, Thanks for the pictures. They are a big help.
I agree with Roger, filed the lugs on my 24 over 50k ago and still working. Guess it depends also on the pocket book, mine at the time was very thin! KGB