My shurflo diaphragm water pump model number 208-110-41?

My pump does not seem to draw up water from the tank to my motor home I have Stripped it down before and got it going. this time to no avail its in my highwayman motor home H reg I need to pump out all the water through system question is how to mend it or can I get it repaired somewhere or can buy the same pump some where
Any ideas I run it with the hoses off should I have felt suction when running in the inlet side ,could it be my brushes in the motor .
Help