not too difficult at all. you just need to clean up the pump surface and block surface and use a liquid sealant, and make sure you torque the bolts to spec. put the new crank seal in after the pump is on of course. you can take the pump off with the old seal in it too, that will make it easier to get out. it depends on your skill level, but it shouldnt take more than 30 minutes with everything already apart.