11-6
AIR BLEEDING
Air accumulation in a hydraulic system will cause erratic action. This may appear as pump failure to the inexperienced
user. For this reason, it is advisable to air bleed each pump before attempting to operate. To remove air from the pump,
open release valve with the pump in an upright position. Operate the pump slowly through the full piston stroke about a
dozen times. Close the release valve. Pump should be ready for use.
TROUBLE POSSIBLE CAUSE CORRECTIVE REPAIR INSTRUCTIONS
(Refer to pump Repair Section)
Pump will not hold pressure
Pump fails to supply pressure
Pump piston does not draw a full
charge. (This is evident by a cushion
effect at the top of the pump stroke.)
Pump piston raises by itself under
pressure
Pump functions properly but will
generate only a given pressure below its
normal pressure maximum
Pump fails to supply greater output at no
load than under load
1 -
2 -
3 -
4 -
1 -
2 -
3 -
4 -
5 -
6 -
Release valve ball not seating properly
Ball Valves not seating properly
Overload valve ball not seating
properly
Large pump relief valve seal faulty
Lack of oil
Air bound pump
Release valve ball not seating properly
Small ball in ball valve circuit not
seating properly
Overload valve ball not seating
properly
Large pump relief valve seal faulty
Air bound system
Lack of oil
Large ball in ball valve circuit not
seating properly
Overload valve not set properly
Large pump relief valve not set
properly
Refer - "Release Valve"
Refer - Pump Valve
Refer - Overload Valve
Refer - Large Pump Relief Valve
Refer - Oil
Air Bleeding Section
Refer - Release Valve
Refer - Pump Valve
Refer - Overload Valve
Refer - Relief Valve
Air Bleeding Section
Refer - Oil
Refer - Pump Valve
Refer - Overload Valve
Refer - Relief Valve
OIL
If the pump fails to operate, check the oil level before attempting any repairs.
CAUTION: Use only Hydraulic Oil when refilling. NEVER USE BRAKE FLUID