Overview
Valve kit for the HydraMaster Hydra Pump II and Hydra Pump 5. HydraMaster part number 000-078-159, listed as Kit, valves for Hydra Pump 2 and 5.
The valves are what make a positive-displacement pump a pump. They open and close on every stroke — thousands of times a minute — in water carrying whatever the machine has picked up.
What it fits
- HydraMaster Hydra Pump II
- HydraMaster Hydra Pump 5
HydraMaster's suggested spares schedule lists it against the Boxxer 421 and the Boxxer 427. Because it is specified by pump, it suits any machine running either pump — check the pump, not the machine.
How worn valves show themselves
Worn or fouled valves and worn seals produce similar symptoms, and telling them apart saves an unnecessary strip-down:
- Pulsing or hammering that has got worse over time usually points at valves rather than seals.
- Pressure that will not reach the set point can be either — but if the pump is also weeping at the weep holes, start with seals.
- A pump that has become erratic rather than steadily weaker — a valve held open by debris, or a valve spring that has broken.
- Sudden loss of pressure with no leak — worth checking the valves before anything else.
Debris in a valve seat is the most common single cause and the easiest to prevent: it usually arrives through a neglected inlet screen or Y strainer.
Related pump parts
HydraMaster also list 078-281, a piston seal kit specific to the Hydra Pump 5 on the Boxxer 427. It is not currently a stocked CCW line — ask us if you need one.
Fitting advice
Keep the valve assemblies in order and the right way up as they come out. They are not all identical and they do not all go back in the same orientation.
Inspect the seats as well as the valves. A pitted seat will not seal against a new valve, and that is a pump repair rather than a kit.
Check and clean the inlet filtration while you are at it. If debris caused this failure, it will cause the next one too.
Frequently asked questions
Does it fit both the Hydra Pump 2 and 5?
Yes — HydraMaster list it for both.
Should I do seals at the same time?
If the pump has done real hours, yes. The seal kit is 078-158 and doing both means one strip-down.
What is in the kit?
HydraMaster does not itemise the contents in the documentation we hold. Ask us if you need to know before ordering.
My pump hammers. Valves or seals?
Hammering and pulsing point at valves more often than seals. If it is also weeping, do both.
Tell us the pump and what it is doing and we will help you decide between a valve kit, a seal kit and both.
