How can I diagnose bad check valves in water pump???

[hanks75]

I have a boxxer 421 that loses pressure (drops to 200psi) when i pull the trigger on my wand. I've been told it a good chance its check valves. what do bad check valves look like. i have a hydra pump. thanks

 

[Charlie Lyman]

It probably needs the seals replaced. I did mine myself, easy enough for a mechanically declined person.

 

[John Olson]

Seals not check Valves are USUALLY the culprit in what you described. You need to open up the pump and inspect it. While it isn't rocket science to replace seals and check valves if you get them backwards (seals) or damage one your SOL. You just bought another whole new kit and they ain't cheap. We just opened up a Pump that someone put the seals in backwards. I am still wondering how on earth the technician never seen nor told the owner that the pump was pissing water like a fire engine. Caused severe damage to the blower as well as water was dumping right on the breather and filled the oil bath with water. Water does not make for a very good lubricant.