Help identifying pressure washer part

[montrose818]

Cat pump, this part leaks, what is it?

Thank you..

 

[bgaidan]

Looks like one of the valves.

 

[AK_F250]

Know the pump model? It's been years since I worked on vac excavators with cat pumps, but I remember their website having good parts diagrams.

 

[Ransil]

Unloader valve