Wide brake drum vs. narrow drum interchangability

[GRW24TVete]

Hi everyone. I'm new to the forum. I'm looking for some interchange info concerning my 1923 Model T.

My Model Ts transmission is very noisy above 30 mph in high speed; it sounds like it's about ready to fly apart. I have a 26-27 transmission with the wider brake drum left over from an earlier T project that was professionally rebuilt but never used. My questions are:

What needs to be changed on my 23 to use this 26-27 transmission? Specifically can I use the 23 3-dip pan or do I need to find a 26-27 4-dip pan?
Can I reuse my 23 hogs head along with the narrow brake band on the wider brake drum?

I would like to keep the 23 pedals and floor boards if possible.

Thanks. Gregg

[speedytinc]

If you want the benefit of 50% more brake You would need the 4 dip pan & the late HH. Top HH mounting ears need modifying or removal.
You can change the pedals.

If you dont want to use the wider brake band, you can still use the front section of the wide drum with a narrow band. No need to change pedals or the pan.

[GRW24TVete]

Thanks for the info. That's perfect! That's all I needed to know.

[Scott_Conger]

No problem with interchange

Problem is with diagnosis. Transmission is locked up solid at 30MPH in high gear. Your noise is elsewhere - almost certainly in the rear end.

[Craig Leach]

Hi John,
You should be able to fit the 26/27 trans in your 3 dip pan & use the 23 hogs head, you just can't use the wide band as it will not be centered
on the drum & you can't use the 26/27 hogs head because the ears collide with the back of the block. Scott is correct everything is turning
together in high gear. T's telescope sound kind of weird. I was once asked to listen to a U/joint that was making noise, being the fourth or fifth
monkey in the circus the diagnosis was U/joint 2 rear end 2 I had never heard or felt either one that was like that. My SWAG was take it apart it
could be a broken crank or bolts in the crank shaft flange. Turned out to be a broken third main cap??? I would do some intensive investigating to
make sure you know what is making the noise. Todays diagnostic tools are great from bore cameras to electronic stethoscopes ( some that have
clamp on sensors& headphones) so you can clamp the sensor on the rear, trans & engine while driving down the road to pin point the noise.
Good luck with this & get back to Ting soon.
Craig.

[GRW24TVete]

My first thought was a bad U joint, so I pulled the rear end to inspect. I found a modern repo U joint with no wear whatsoever. I next moved to the rear end and removed the torque tube. I found the previous owner had rebuilt the entire rear end including modern roller bearings for the pinion shaft, new ring gear, new axle shafts, modern outer wheel bearings, bronze thrust washer, etc. So I'm confident the problem is not in the rear end.

This car has significantly more band chatter than other Ts I've driven in the past. Maybe the transmission noise could be coming from a loose flywheel. I guess I will have to take it apart and do more investigating.

[speedytinc]

Maybe a loose magnet keeper. Even a bendix that isnt retracting.

[GRW24TVete]

I could see where that could be a problem, but I've already checked those. Everything is smooth when I hand crank the engine.

[babychadwick]

Hi John,
You should be able to fit the 26/27 trans in your 3 dip pan & use the 23 hogs head, you just can't use the wide band as it will not be centered
on the drum & you can't use the 26/27 hogs head because the ears collide with the back of the block.....

Are you sure about that? I have an early (generator) not 26/27 block with a 26/27 hoggshead and early transmission here. The ears on the hoggshead clear the block. The brake band is not centered on the drum as expected. Also the 4 dip pans have a bulge to accommodate the larger drum/band. It may clear in a 3 dip without the band over the entire drum, not sure what the clearance would be.

[Craig Leach]

Hi Chad,
My experience has been that the bulge in the back of the earlier block collides with the ears on the 26/27 hogshead. I just barrowed a 27 block
to mock up a speedster ( the engine going in it will have a 26/27 hogshead on a early block with the ears cut down) so I want the pedals to fit.
My recollection is the wide brake will fit in a 3 dip pan but the wide band will not & it might be good to cut 3/16 off the end of the wide drum
to do it. Gregg, All previous branches of the diagnostic tree would be good info in the first post.
Craig.

[babychadwick]

Should fit...

I assume you intend to run a 4 dip pan as a 3 dip won't fit with the band on the 26/27 hoggshead.

[Craig Leach]

Hi Chad,
Good to hear that some 26/27 hogsheads will fit the early blocks I just haven't had that kind if luck with that combination.

Craig.

[Original Smith]

A 26-7 wide drum can be turned down to the early style by a competent machinist. Just be sure to get the lip done at the same time. The added benefit is the brake shoes.

[babychadwick]

Hi Chad,
Good to hear that some 26/27 hogsheads will fit the early blocks I just haven't had that kind if luck with that combination.IMG_3692.jpgIMG_3691.jpg
Craig.

Guaranteed to go on when the engine is out of the car. Once in the car deals off lol.

[Dan Hatch]

Early blocks are square on the back of block. Later blocks have a sloping rear. Easier to remove HH. No sure of change date.

[Allan]

The lug ears on the 26-7 hogshead in Craig's post have been modified to allow it to fit. Normally the block side of the ears is flat against a flat land on the 26-7 block.
The 26-7 wide brake drum and its attendant driven plate will fit in a three dip pan with no modification. The wide brake band will not fit. There is nothing to stop you from using the narrow band on the wide drum, with the attendant hogshead with its evenly spaced pedals.

Machining the wide drum to the same width as a narrow one is pointless. The drum will fit as it is. The benefit is there is a continuous drum surface for the band linings. Often when building a transmission with the small drums it is difficult to get a drum and a driven plate with matching diameters. As the outside diameter of the driven plate forms part of the brake drum surface, it is preferable that there be no step between the diameters of the two components. Using both the 26-7 drum and its driven plate also removes the necessity to modify the bolt circle holes in an earlier driven plate to make it fit a later drum.

All that said, the restored chassis I bought with the Holden body on my 1924 tourer has had a relief worked into a three dip pan so the wide band will fit! It has the usual 24 hogshead with equal pedal spacings, so if a wide band is in use, the ears have to have been shifted forward of centre on the bands. I have yet to have a need to check out just what has been done. It hasn't broken, so I haven't had to fix it yet.

Allan from down under.