MTFCA Forum

Pulled apart my transmission today... Had a cracked brake drum in two places. Ordering a new one.

Showing pics of old brake drum: Outside of clutch basket: Inside of clutch basket: Over half the clutch disks were either cracked or broken. Ordering Watts disks from R.V. Anderson.

Looks like I can't add more photos, so will in a reply.

Clutch disks examples: Slop/oplay in transmission. Seem excessive? All the bushings appear to be nice and tight... In triple or driven gear? Might this be some of the rocking back and forth I get when stopping?

https://youtu.be/UHnA6tFybW8

I ordered the transmission book from Snyder's..... But of course, started without it.

Wondering if I need a new clutch basket?

Low drum is a bit pitted, but seems solid, and bushing tight. Thinnest point is .128".

I made a clutch spring compresser from a couple flanges from Tractor Supply, as I didn't have any spare wheel hubs.

The clutch discs were cracked because the brake drum lugs are all chewed up. About half of the large plates in the transmission in my 23 runabout were broken too. The watts clutch works well, but with your new brake drum and some replacement original steel plates the stock clutch will work just as well. Save you a little money.

Stephen

The stock clutch, properly adjusted, with a good used spring (95 to 110#’s at 2”compression) will not slip and is nice and smooth. It also protects the engine and drive-train from unnecessary shock loads...

Adam wrote: ↑

Sun May 24, 2020 8:56 pm

The stock clutch, properly adjusted, with a good used spring (95 to 110#’s at 2”compression) will not slip and is nice and smooth. It also protects the engine and drive-train from unnecessary shock loads...

I couldn't agree more

Stephen

The spiral mark on your clutch basket is most likely a manufacturing mark and harmless. BUT, given the nature of all the other damage you've got, check it out to be sure. Clean it up and see if the spiral continues down in and through the slot, as a crack would do. I think you'll find that it won't, but again, check it out.

And yes, this would explain the rocking back & forth when you stop.

I have the watts clutch in my 26 touring and have enjoyed the free neutral, but it is not near as smooth as the stock one in my 25. The stock one is harder to start in the winter. Looks like you are headed in the right direction, good luck.

At first glance, my triple gears do not appear to be worn, (although, admittedly, I need to take a much better look) and the bushings don't have wobble. All 3 triple gears plus the center driven gear all fell off the drum cluster when I pulled them off .... well ... they stayed on their shafts, at least, except for the center driven gear.
My question is, should the center gear move around the middle, when the triple gears are moved? By that, I mean it turns, but doesn't stay in the middle of the 3 triples, as it isn't on the brake shaft. The 2 keys came out when I pulled the drum cluster, as well.

I'm looking for the source of the play in the YouTube video, posted above.

Dennis,

The center gear, (a.k.a. the sun gear), should be a heavy press fit on it's shaft. They can be a bear to remove without the right puller. They should not fall off. As an aside, the clutch basket should also be a press fit on the main shaft.

Looking closely at your triple gear photo, at least 2 of the bronze bushings appear to seized on the triple pins, with the gears rotating about the bushing, rather than the gear/bushing assembly rotating about the pin. Sorry to add to your work list...

Hi, Jerry ...

Yes, the clutch basket was a pretty tough pull. My puller wouldn't stay in the basket pull holes from the inside, so I had to pull with the arms on the outside. No harm, no foul, I guess.

Hmm ... So I guess I need to check where the issue is on on the sun gear, then. I'll try putting it back on the shaft, to see how it fits. I assume it will still be loose. Need to check the brake shaft end to see if shows wear, and if not, then a new sun gear is in order?

Boy, these piece parts add up, eh?

If you find your brake drum shaft is worn, I make driven gears with undersize bores that allow use of slightly worn shafts.

Dan ...
Very good ... what should the shaft diameter be? ... and/or, what is the inside measurement of your driven gear?

Ok so it's good that the clutch drum had to be pulled off, but what was also said is"plus the center driven gear all fell off the drum cluster". That is not good. It too needs to be a press fit, not loose on the shaft. So my take would be, you need a better driven gear too. Are you getting the brake drum with or with out the shaft?

Mark... I am off to measure the drum shaft now... Have to box up to send to R.V Anderson, anyway. If it's too narrow at that end, yes... I'm need to have him add a new one, or get an undersized drven gear from the previous poster. I don't know what the proper diameter is, but it should measure similar to further up the shaft.

The driven gear bore per the Ford drawing is 1.651"/1.652"

Dan

it's great to know you make these U/S gears! That was news to me. I wonder how many "stealth" parts exist for the market-place?

That has to be one of the most chewed up brake drums I've seen and I've taken quite a number apart !!!

The readings I get with my calipers are 1.650" ID on the driven gear, and 1.651 on the area of the brake shaft where the 2 keys are, with 1.652 in the 'unused' area if the shaft above where the opposing holes are, then back to 1.651 in the bushed area, down next to the drum.

Interestingly, the driven gear won't just slide back on. With some effort, I can 'wobble' it back on, maybe 3/16".... To go further, I would have to drive it on.

Should I ask for the drum back to keep as an example of a terribly bad drum?

If that gear was in my shop, it would recieve 9 separate measurements using telescoping gauges and an appropriately sized micrometer that had been double checked for "zero" against a 1" standard block (there are admittedly other ways to measure, including inside mics, but I find telescoping gauges combined with a good outside micrometer to be satisfactory for the accuracy needed). Those 9 measurements, mapped, would let you know what's really going on. You've already found a slip fit situation for some portion of the assembly which the dial calipers did not pick up. Though they appear to be built for it, they really are not the tool for this job.

Good quality dial calipers are my go-to tool in my shop but do not trust them to be accurate under .002" if it is an important measurement, and this one is. ID measurements can be particularly problematic and give bad surprises even if you're used to using them carefully and correctly.

As an aside, if you're used to the method, standard Starrett hand calipers can guide you to a remarkably close size "to size" on a lathe and save you from constantly double checking with measuring tools prior to going in for the final cut, but that's an entirely different subject.

More than likely both the driven gear and the brake drum shaft are shot because the gear would have been moving slightly on the end of the shaft. Good driven gears are easy to find and cheap. Find a better one and you'll be all set.

Stephen

Scott... I wish I had the skill set and tools to do proper measuring and comparison. I have sent my old drum and shaft to R.V. Anderson to mount one of his new break drums to my old shaft. If he makes the shafts as well... I will ask him to go ahead and install one of his, instead. Otherwise, one I get it back, I'll take the setup to a local machine shop, and have the shaft turned to match one of Dan's (I think I got his name right) undersized gears.

Thanks all for your input!!

Dennis

I reread my post and believe I came across harshly, when I did not mean to. Dial Calipers are in everyone's shop and are generally considered the final word by their users...I simply wanted to warn you to not put too much stock in what they were telling you for this job. General machine shops often work to +/- .005", while precision work is usually +/- .002. This is work that really needs to be understood to 1/2 thou (.0005) and an awful lot of folks don't realize that. Please accept my appologies if you were offended.

No problem, Scott... I wasn't offended at all. It is good to remember, that some aspects of the T are not best left to 'farmer hacks'. I appreciate knowing, that this is one of them... That proper tolerances need to be maintained. As it 'kinda starts to go on' now.. I would otherwise been inclined to get out the hammer and a block, and schmuck it back on, when the time comes.

If Dave's Restoration and Machine makes the shafts, then I'll just have him mount that... Otherwise, I'll have a machine shop clean minne up to match a slightly undernoted driven gear. I am, after all, as part of this rebuild, looking for sources of 'slop', that I can mitigate in the process.

Take care, and be safe!

Dan McEchern... I sent you a PM. Thanks,

Dennis