Service Manual User guide

MAINTENANCE PROCEDURES - RELIEF VALVES

DISASSEMBLY

The cartridge type service port reliefs used in the Husco valves are of the pilot poppet type with external

adjustment. Any malfunctioning is usually the result of foreign matter lodging between the piston, relief

valve poppet, and check valve.

To service, clean the surrounding area and remove the complete relief valve cartridge.

The design, of the pilot poppet and pilot poppet seat provides positive seating and seldom requires any main-

tenance. Therefore, the pilot section, check valve poppet and other internal parts, can be removed from the

cartridge without disturbing the valve setting. Disassemble these parts and examine for foreign matter.

INSPECTION AND REPAIR

Examine the seat in the main valve housing, if grooves or ridges are present, the valve must be returned to

Husco for re-machining.

All seats and seating surfaces should be smooth and free of nicks, scratches or grooves. Examine O-rings and

back-up washers for any damage. Replace damageed or faulty parts. All moving parts should slide, freely

with only seal friction present.

If operating difficulties indicate that the pilot poppet is leaking or sticking, remove internal parts of the

pilot section and follow same procedure as above.

ASSEMBLY

After inspecting andl cleaning, immerse all parts in hydraulic oil and re-assemble. Since pressure setting was

not disturbed, unit can be tested for proper functioning under actual working conditions.

There are several variations to service port relief. However, all are similar in nature regarding service

and repair (see Maintenance Procedure Relief Valves, Page 7).

TROUBLE SHOOTING - SERVICE PORT RELIEF CARTRIDGE

. Service Port Relief Cartridge

FIGURE 31

FIGURE 32