Two mechanical shaft seals for both, drive-end and non drive-end of the pump.
When mechanical shaft seals are renewed on your Truck Master 2500, the bearings of the pump must also be renewed.

When you must renew the mechanical shaft seals on the pump, you must first dismantle the bearings, which will cause an internal damage on the bearings. Although, not always obvious to the eye an internal damage of bearings always occurs when they are dismantled from the pump. Subsequently, they must be replaced for the pump to operate properly.