HydraMaster Boxxer 421, Owner'S Manual

Page: 48 / 179

HydraMaster Corporation
Page 6-2: High Pressure Pump
Boxxer 421
Service
T
he next few pages explain how to disassemble and inspect all easily-serviceable
parts of the pump.
Do not disassemble the hydraulic end unless you are a skilled mechanic. For
assistance, contact HydraMaster (425-775-7275) or the distributor in your
area.
Servicing the Valves (See Figure 6-1)
1. Remove the hex valve plugs;
top—discharge
bottom—inlet
2. Unthread the valve plug and examine the O-ring under the plug for cuts
or distortion. Replace it if it is worn. Lubricate new O-rings before installing.
3. Grasp the valve retainer by the tab at the top with needle-nose pliers, then
remove the O-ring at the bottom of the valve chamber.
4. Inspect all valve parts for pitting, gouges, or wear. If wear is excessive,
replace valve assembly.
5. Reinstall valve assemblies:
a) Using a clean towel, clean the valve chamber.
b) Install the O-ring into the high pressure manifold.
c) Install the valve assemblies into the high pressure manifold
(the metal side of the valve faces the manifold).
d) Replace the O-ring on the hex valve plug.
e) Torque the plug to 30 foot pounds.