Is it cheating if I leave the rear hub brake lever and cam on and just clean it and paint it without taking it off?

Just curious how it comes apart does it just twist off?

Unless you need to replace the cam, lever and or bushing I would leave in place. The lever is secured with pins (two if prior to 26, one if after) these need to be removed to separate the lever from the brake cam shaft. To put everything back together, use new pins and peen over both ends.

If the bushing is worn, I'd replace them. Otherwise, no need to disassemble. There's a left and right lever.

Sometimes it's best to leave sleeping dogs lay!

"There's a left and right lever. "

The levers are the same for both sides; the cams are different.

Usually, if the car has miles on it, they need replacing, and it's not an easy job!

If you have to remove a lever or both because of wear use a torch to heat the lever and roll pin, cool them off and carefully use a punch to drive out the roll pin.
Hopefully yours aren't worn enough to have to do that.
But if they are worn do it now and not wish you had done it later. Been there and done that!

How do I know if they are worn?

This video shows the sounds from worn front spindles, but it applies to many other locations.

Wiggle the shaft up and down or back & forth, if you feel slop and it makes a clunking sound, it's worn.

https://www.youtube.com/watch?v=FQ4PWhl2QGQ

It wiggles. I tried hearing it up and grinding the head of the pins off then punching them out. Nothing so far.

Cut the shaft off on the cam end. Drive out the shaft, put it in a vice in the drill press, mill, or clamp it in your lathe, however you see fit. Drill out the old shaft just past the pins. Grind off the head of the pins and drive them into the cavity made by the drill bit. Once they are out drive the remainder of the shaft out. Install new bushings in the housing. Fit brake cam to bushing. Install cam lever onto cam shaft and pin it. Nothing a few hours in the garage can't solve. Pay attention and keep the right cam with the right side. If the lever holes are worn, weld them shut, center punch and drill them out to the correct size.

Is there supposed to be a pit in the backing plate or is that wear too? Does it need to be filled?

That area is defiantly worn away. It also looks like someone has put a shim between the inner bushing and the brake actuator/cam shaft. I'm not a welder but I think the worn (pit) area can be repaired. You will need a new bushing.

How is the bushing changed out? I can braze and MIG.

The bushing is just a press fit. Press or knock it out with a suitably sized driver.

New cams, arms, pins, and bushings are available from the vendors.

Ignacio, Is that a picture of one of your 1914 style rear axle housings with the worn e-break cam area? If so now is the time to get good and correct 1922 housings, they aren't hard to find.

@kevin yes that is the 1913-14 housings. Shouldn't I keep them original?

Ignacio, You must misunderstand. You will keep your 1914 housings for now, or maybe sell them, but not use them in your 1922 car. You should be able to buy from some one in your local Model T club 1922 type housings in good condition and use them in your rebuild with out having to weld up e-brake areas of backing plates.

They came with the car I kinda want to keep them together. Plan is to push out the bushings. Braze the worn part and redrill it from the other side on a drill press. What size hole is it?