Hydraulic systems troubleshooting varies according to the complexity of the system and the components in the system. It is, therefore, important that the technician refer to the troubleshooting data furnished by the manufacturer.
(1) Relief valves repair... Lack of pressure in a system can be caused by a sheared pump shaft, defective relief valves needing repair, regional aircraft control valves, the pressure regulators, unloading valves stuck in the "kicked-out" position, lack of fluid in the system, the check valves installed backward, or any health that permits free flow back to the reservoirs or overboard. If a system operates satisfactorily with a ground test unit but not with the system pump, the hydraulic pumps should be examined.
(2) If a system fails to hold pressure in the pressure section, the likely cause is the pressure regulator, an unloading valve, leaking relief valves nedding repair, or a leaking check valve.
(3) If the pump fails to keep pressure up during execution of the subsystem, the pump may be worn or one of the pressure-control units may be leaking.
(4) High pressure in a system may be caused by a defective or improperly-adjusted pressure regulator, an unloading valve, or by an obstruction in a line or control unit.
(5) Unusual noise in a hydraulic system, such as banging and chattering, may be caused by air or contamination in the system. Such noises can also be caused by a faulty pressure regulator, someone else pressure-control unit, or a lack of proper assembler action.
Pneumatic Torque Wrench Troubleshooting
Aviation component repair.
Commuter aircraft hydraulics overhaul, maintenance of hydraulic system components, involves a amount of standard practices together with specialized procedures set forth by manufacturers such as the transfer of relief valves, actuators, and other units, together with tubing and hoses. Care should be exercised to forestall system contamination damage to seals, packings, and other parts, and to apply proper torque in connecting fittings. When installing hydraulic fittings, valves, etc. All the time lubricate the threads with hydraulic fluid.
Overhaul of hydraulic and pneumatic units is ordinarily terminated in approved repair facilities; however, transfer of seals and packings may be done from time to time by technicians in the field. When a unit is disassembled, all O-ring and Chevron seals should be removed and replaced with new seals. The new seals must be of the same material as the original and must carry the accurate manufacturer's part number. No seal should be installed unless it is easily identified as the accurate part and the shelf life has not expired.
When installing seals, care should be exercised to ensure that the seal is not scratched, cut, or otherwise damaged. When it is principal to install a seal over sharp edges, the edges must be covered with shim stock, plastic sheet, or electrical tape.
The transfer of hydraulic units and tubing ordinarily involves the spillage of some hydraulic fluid. Care should be taken to ensure that the spillage of fluid is kept to a minimum by windup valves, if available, and by plugging lines immediately after they are disconnected. All openings in hydraulic systems should be capped or plugged to forestall contamination of the system.
The point of the proper torque applied to all nuts and fittings in a system cannot be over-emphasized. Too much torque will damage metal and seals, and too small torque will consequent in leaks and loose parts. The proper torque wrenches with the standard range should be used in assembling system units.
Aircraft Hydraulics Overhaul