I took the rear fender off the bed and there was some banging going on to get the bolts out. Took off the rear wheel as well (including jacking it up to get wheel off).

The brakes worked prior to this process. Now the pedal goes all the way to the floor. Everything is so coated in rust and dirt, I wouldn't even know where to start to look for leaks, etc (plus my limited knowledge of drum brakes).

It is a 51-1 ton with drum brakes on all wheels.

Anyone have any ideas where to begin?

Thanks,
James