HDD 209W - Heavy Duty Diesel HydraulicsCredits: 3
Practices the service and repair of heavy duty diesel hydraulics. Practices NATEF tasks related to heavy duty diesel hydraulics.
Prerequisite(s): HDD 202 and HDD 206 both with a minimum grade of "C" (2.0)
Corequisite(s): HDD 203W , HDD 207 , and HDD 210
Lecture Hours: 45 Lab Hours: 25
Meets MTA Requirement: None
Outcomes and Objectives
- Complete NATEF tasks related to hydraulic system of heavy duty diesel vehicle as listed below.
- General Hydraulics System Operation
- Identify system type (closed and open) and verify proper operation.
- Read and interpret system diagrams and schematics.
- Perform system temperature, pressure, flow, and cycle time tests; determine needed action.
- Verify placement of equipment /component safety labels and placards; determine needed action.
- Identify system fluid type.
- Identify causes of pump failure, unusual pump noises, temperature, flow, and leakage problems; determine needed action.
- Determine pump type, rotation, and drive system.
- Remove and install pump; prime and/or bleed system.
- Inspect pump inlet for restrictions and leaks; determine needed action.
- Inspect pump outlet for restrictions and leaks; determine needed action.
- Filtration/Reservoirs (Tanks)
- Identify type of filtration system; verify filter application and flow direction.
- Service filters and breathers.
- Identify causes of system contamination; determine needed action.
- Take a hydraulic oil sample for analysis.
- Check reservoir fluid level and condition; determine needed action.
- Inspect and repair or replace reservoir, sight glass, vents, caps, mounts, valves, screens, supply and return lines.
- Hoses, Fittings, and Connections
- Diagnose causes of component leakage, damage, and restriction; determine needed action.
- Inspect hoses and connections (length, size, routing, bend radii, and protection); repair or replace as needed.
- Assemble hoses, tubes, connectors, and fittings in accordance with manufacturers' specifications; use proper procedures to avoid contamination.
- Inspect and replace fitting seals and sealants.
- Control Valves
- Pressure test system safety relief valve; determine needed action.
- Perform control valve operating pressure and flow tests; determine needed action.
- Inspect, test, and adjust valve controls (electrical/electronic, mechanical, and pneumatic).
- Identify causes of control valve leakage problems (internal/external); determine needed action.
- Inspect pilot control valve linkages, cables, and PTO controls; adjust, repair, or replace as needed.
- Actuators (Comply with manufacturers’ and industry accepted safety practices associated with equipment lock out/tag out; pressure line release; implement/support (blocked or resting on ground); and articulated cylinder devices/machinery safety locks.)
- Identify actuator type (single/double acting, multi-stage/telescopic, and motors).
- Identify the cause of seal failure; determine needed repairs.
- Identify the cause of incorrect actuator movement and leakage (internal and external); determine needed repairs.
- Inspect actuator mounting, frame components, and hardware for looseness, cracks, and damage; determine needed action.
- Remove, repair, and/or replace actuators in accordance with manufacturers’ recommended procedures.
- Inspect actuators for dents, cracks, damage, and leakage; determine needed action.
- Purge and/or bleed system in accordance with manufacturers’ recommended procedures.
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