Brake drum

[ozimmerman]

#1 I didn't pay attention during the take-apart faze... and I can't tell from my service manual, where should the brake drum line up? Does it go all the way in or do I want it so that the brake pad is centered?

#2 The next problem is that when I tighten the retention screw, the drum just slips off of the key. Any thoughts on that?

[tst]

the drum has a key way and should fit tight on the axle, it will bottom out on the axle and cannot be pushed any further when it is installed

[Dale Finch]

As Tim said, push/tap the drum all the way until it hits the shoulder on the shaft.
Once the final is installed, the brake band should be centered...provided the pins on either side of it are in the holes of the casting AND the bands are oriented correctly (not upside down)...sometimes difficult to figure out with the toggle style bands!

Make sure that when you installed the drum that the locking nut was backed off far enough to make sure the set screw is actually "digging into" the key. Only then, tighten the lock nut very tight! If access to that set screw & lock nut is a problem, you can rotate the shaft until they line up with the brake rod hole in the housing.

[Glen]

#2 The next problem is that when I tighten the retention screw, the drum just slips off of the key. Any thoughts on that?

Hi,
While the drum is off the shaft, check the threads on the retaining bolt. It sounds like the threads might be bad, or tight, preventing the bolt from turning in enough to tighten on the key.
Back off the lock nut plenty, and see if the bolt screws easily down into the threads in the drum, farther than it would normally go.
Repair the threads, or buy a new lock bolt if needed. TM Tractor has them.
Tighten the lock nut well when it is together.
If the drum has been run with the bolt loose, or no key in the shaft, check the ID of the drum and the surface of the shaft for wear, or damage. They should fit together tight.
The spacer on the brake band pin has to be the right way so the band is aligned in the right position on the drum. The spacer goes in, facing the Cub, on the right and left brakes.
When you put the final drive on the Cub, be sure both ends of the brake band pin are in the holes for it.
It can break the castings to tighten the bolts holding the final drive on, if the pin is not in it's holes.
Below is a picture showing the pin and spacer, it's the right side. It is a Cub with the 2nd style brakes, but the 1st style has a spacer there too.

[Gary Dotson]

Your description sounds like you may have a wallowed out bore in your drum. As others have mentioned, it must be a tight, almost press fit, on the shaft. If your’s is a sloppy fit, good used ones are out there and new ones are also available.

[ozimmerman]

Thanks for all the great info. You guys are certainly on to some things. Set screw is new, as the old one was toast after 70+ years. I did get the screw tight and thought I was good to go, but the drum definitely does not fit tight with the shaft. I don't know what they look like new, but the keyway in the drum was barely even noticeable. I took a file to it to give it an edge, but I now after seeing these posts, I understand that the drum is almost certainly shot. There was no key when I originally pulled the final. There is also a measurable gap between the shaft and the drum. It is hard to describe, but the drum sits elevated above the shaft by the key. Sounds like another order to TM. I think this is order #4 or 5 on just this project; postal service must love me for paying all this shipping. Will chalk it up as part of the fun of the learning process.

[Matt Kirsch]

Yeah, that sounds like you've got a severely worn drum.

JP Tractor Salvage can set you up with a good used drum.

Here's what a new one looks like. As you can see it has a very distinct keyway.

[ozimmerman]

Uh... yeah. I will try to remember to get a photo of mine, for fun.

[Dale Finch]

You probably need to measure the axle shaft, too, in case it has been worn down. They probably are also available from JP. Maybe they or someone else can give you measurements for a good one so you can compare sizes.

Here's one from TM Tractors:
http://www.tmtractor.com/new/fr/662fp.htm

[Jim Becker]

I don't know the proper shaft diameter. Somebody may be able to post it. If you also have the other side apart, you could test fit the other drum.

[Bob McCarty]

I don't have a new one to measure, but have one that is a tight fit in a drum. It measures 1.502-1.504. So if yours is close to 1.5" it should be good to use. Measure in multiple places to make sure it is round.

[Gary Dotson]

I had one, a few years back, that was severely worn, as yours is, in my case, the shaft was undamaged. The shaft is a lot harder than the, soft, cast iron drum.

[Dale Finch]

I had one, a few years back, that was severely worn, as yours is, in my case, the shaft was undamaged. The shaft is a lot harder than the, soft, cast iron drum.

Same here... I replaced the worn brake drum and the (used) replacement drum fit fine...with good keyway and new woodruff key set really tight.

[Glen]

Hi,
Hopefully you replaced the oil seal in the transmission, and final drive, that the upper shaft runs on, while you have the final drive apart, if they weren't replaced lately.

[ozimmerman]

Hi,
Hopefully you replaced the oil seal in the transmission, and final drive, that the upper shaft runs on, while you have the final drive apart, if they weren't replaced lately.

Any tips on getting to the oil seal? I have the left final off.