i have a 1969 ford 3000. when i bought the tractor it had a little bit of brakes on the left side so i pulled into it and found the axle seals were bad so i repacked the bearings replaced the seal and shoes on both sides cleaned everything and put it back together and adjusted them up till i have a good pedal now when i step on the pedal you can hear the shoes rubbing the drum but i cannot stop it in a 50 acre field! could the drums need to be turned or do they make differant grades of shoes like semi metallic any ideas would be app. thanks evans