I replaced te cam and backing plate and have regained great braking power. Both directions are relatively equal, but it is still a little better in forward than reverse,but more than acceptable.I did not see much wear in the cam or backing plate, but it did make a difference. Thanks for the tip.
Jules

Thanks for the insight Liftdoctor. As a matter of fact I am servicing one now that has this problem. I installed new shoes and actuating arms, and drivers(the small trapazoid shaped inserts in the middle of the shoes), and emeried the drum, which is in excellent condition. I agree about the nearness of the hyd. breather (have seen this also), but my recent repairs have eliminated this.I will try a new backing plate, and cam and will post the results.This seems a logical answer.

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.