Here is what I do for the drive motor brakes. I sand the shoes and drums with emery cloth. Also, when the hole in the backing plate wears and gets egg shaped, it will cause it to brake harder in one direction than the other. You then need to replace the backing plate and cam. I have always felt that the breather for the hydraulic tank is too close to the brakes. The brakes pull in the oil vapor from the hydraulic tank and it makes the brakes grabby. The truck will slide the tire in forks forward direction. In reverse, when you brake, the wieght gets tranfered to the drive tire and it brakes very hard. Cleaning the shoes and drum with emery cloth is the best thing you can do.

For the caster brakes, sand the shows and take some tension out of the spring that applies the caster brake.