Martin, I've was driving a 310 when the PS pump belt broke and I guarantee it's no fun trying to steer and brake with no power assist! A leaky pump is probably not quite as severe but probably not far behind on the pucker factor scale
Good thing he found it now rather than when you're out on the road trying to source a replacement.
Air forums # 1674
1974 20' Argosy Motor Home
1974 31' Excella trailer (parting out, as of 4/1/2015 I have wheels, brake drums, windows & holding tanks left to sell)