How can i bleed my shurflo Trailking 7 water pump?

When you turn the tap on in my motorhome the waterpump makes a loud juddering noise and the pipes that go to the hot/cold taps in the kitchen bang together.I have a shurflo Trailking 7 fitted and wondered if it might need bleeding,is there a way i can do this myself only it doesnt sound a very technical job ?. I have taken it off and tried to suck water through it,apart from making me go blue it hasnt done a thing. Is there a bleed button/screw that does this....?????
any suggestions would be really appreciated.

Simon
December 2009