DRESSTA TD-25M EXTRA, Service Manual

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HYDRAULICS
SECTION 10
Page 19
DRESSTA TD-25M EXTRA
TEST AND ADJUSTMENT
Ripper Lift
NOTE: Before performing cylinder time cycle test, perform cylinder blade tilt test to insure that
middle pump is correct.
NOTE: Before performing cylinder time cycle test, perform ripper lift cylinder drift test to insure that
control valve, cylinders and valves are performing satisfactorily.
If there is no excessive drift when ripper lift control is in HOLD position, but slow load speed,
slow response or low power is present in RAISE position, problem could be either hydraulic
pump or pressure relief valve. Loss of flow can be caused by pressure relief valve not
sealing, allowing oil to flow into return to reservoir passage. Refer to Paragraph 5, RELIEF
VALVE PRESSURE TEST.
To check pump, following time cycles should be observed when raising ripper.
1. Position machine so that ripper will not touch ground in its fully lowered position. Run engine
at full throttle.
2. Starting with ripper in its fully lowered position, put control lever in RAISE and record time
it takes ripper to reach full raised position. Repeat this procedure several times and average
time readings.
3. Lift cycle should take not more than 1.8 seconds. If average cycle time is more than
1.8 seconds, front pump should be repaired or replaced as necessary.
NOTE: This check should be made only in ripper raising cycle.
9. PISTON PACKING TEST
Blade Tilt or Blade Tilt/Pitch and Ripper Cylinders Test
1. Position machine so that cylinder(s) to be tested can be completely extended. Start engine,
completely extend cylinder(s) and place control lever in HOLD. Stop engine. Remove rod
end hose.
WARNING! During next step, pressurized oil may be expelled from cylinder.
2. Hydraulically extend cylinder(s) again and check rod end port of cylinder(s) for oil flow.
NOTE: Check tilt cylinder for tilt/pitch model from both sides .
Blade Lift Cylinder Test
1. Disconnect the one of blade lift cylinder piston rod from the blade. Start the engine and retract
cylinder to position slightly extended. Stop the engine. Tie the end of rod to the head of cylinder.
Remove rod end hose.
WARNING! During next step, pressurized oil may be expelled from cylinder.
2. Hydraulically extend cylinder(s) again and check rod end port of cylinder(s) for oil flow.