308C CR Excavator Hydraulic System – Gear Pump (Pilot) – Test

Illustration 1 g00730416

Flow meter tool layout

(1) Swing motor

(2) Connector

(3) 6V-9837 Swivel Tee

(4) Makeup line

(6) 6V-9851 Elbow

(7) 4C-9910 Portable Hydraulic Tester (flow meter)

(8) Pilot line (oil delivery from pilot pump)

(9) 6V-9829 Cap

(10) 092-3635 Connector

(11) 3K-0360 O-Ring Seal

(12) 5P-5777 O-Ring Adapter

(13) Elbow

(23) 6V-8397 O-Ring Seal

(26) 6V-8398 O-Ring Seal

(27) 1U-7642 Coupling

(28) 7M-8485 O-Ring Seal

(29) 4C-6482 Nipple assembly

(30) 4C-6481 Coupler assembly

(31) 4C-8767 Coupling

(32) 5P-1010 Sleeve

(33) 5P-0201 Hose

(34) 8C-9026 Adapter

(35) 6K-6307 O-Ring Seal

NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.

Refer to Special Publication, NENG2500, “Caterpillar Tools and Shop Products Guide” for tools and supplies suitable to collect and contain fluids on Caterpillar products.

Dispose of all fluids according to local regulations and mandates.

  1. Position the machine on level ground.
  1. Stop the engine.
  1. Release the pressure in the hydraulic system. Refer to Testing And Adjusting, “Hydraulic System Pressure – Release”.

    Illustration 2 g00730423

    Circuit diagram

    (1) Swing motor

    (2) Connector

    (3) Tee

    (4) Makeup line

    (5) Main control valves

    (6) Swivel elbow

    (7) Portable hydraulic tester (flow meter)

    (8) Pilot line (oil delivery from pilot pump)

    (9) Cap

    (14) Engine

    (15) Right pump

    (16) Left pump

    (19) Multitach

    (45) Pilot pump

  1. Install the following tools in accordance with the flow meter tool layout and the circuit diagram. Refer to Illustration 1 and Illustration 2.
    1. Install multitach group (19) on engine (14) .
    1. Remove pilot line (8) from elbow (13) at the pilot filter.
    1. Install seal (23) and cap (9) to the open end of elbow (13) .
    1. Assemble and install seal (23), connector (10), seal (11), connector (12), seal (28) and nipple assembly (29) to pilot line (8) .

      Illustration 3 g00858725

      Swing motor

      (1) Swing motor

      (2) Connector

      (4) Makeup line

    1. Disconnect makeup line (4) from connector (2) at swing motor (1) .
    1. Assemble and install seals (26), tee (3), elbow (6), coupling (27), seal (28) and nipple assembly (29) to connector (2) at swing motor (1) .
    1. Install seal (26) and makeup line (4) to tee (3) .
    1. Connect flow meter (7) and the test hoses between nipple assembly (29) at pilot line (8) and nipple assembly (29) at the swing motor.

    ------ WARNING! ------

    To prevent personal injury or equipment damage from failure of the hydraulic test equipment or associated circuit components because of blocked pump flow, make sure that the test equipment valves are fully open before starting the engine.
    ----------------------


  1. Start the engine.
  1. Place the machine controls at the following settings: engine speed dial “10” and Low idle switch OFF. Refer to Testing And Adjusting, “Engine Performance – Test” for engine rpm settings.
  1. Place the hydraulic activation control lever in the UNLOCKED position.
  1. Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).

    Illustration 4 g00729705

    Portable hydraulic tester (flow meter)

    (7) 4C-9910 Portable Hydraulic Tester (flow meter)

    (19) 9U-7400 Multitach Tool Group

    (41) Valve

  1. Slowly turn valve (41) on flow meter (7) clockwise until the pressure gauge on the flow meter shows a reading of 4100 kPa (595 psi).
  1. Record the pilot pump flow and the engine speed at 4100 kPa (595 psi) in Table 1.
Table 1
Pump Flow Test    
Oil temperature C° (F°)        
Engine speed (rpm)        
Flow measured liter/min (US gpm)        
Flow corrected liter/min (US gpm)        
Specification for pump flow liter/min (US gpm)     New     17 L/min (4.5 US gpm) (1)    
Service limit 14 L/min (3.7 US gpm) (1)    
( 1 ) Minimum

Note: Specifications for pump flow are based on an engine speed of 2100 rpm. To get more accurate test results, measured flow should be corrected by the following calculation.

Table 2
Corrected flow     =     Measured flow x 2100 rpm    
measured rpm  

Flow measurements must be done in pressure rise.