HYDRAULICS SECTION 10
Page 17
DRESSTA TD-25M EXTRA
TEST AND ADJUSTMENT
Legend for Fig. 10.10
1. Ripper Lift Cylinder
2. Ripper Pitch Cylinder
3. Blade Lift Cylinder
4. Quick Drop Valve
5. Three Spool Control Valve
6. Blade Pilot Valve
7. Ripper Pilot Valve
8. Directional Valve
9. Shuttle Valves
10. Unloading Valve
11. Blade Tilt/Pitch Cylinder
12. Blade Tilt Control Valve
13. Hydraulic Pump Assy
14. Hydraulic Reservoir
14A. Suction Strainer
15. Breather Valve
16. Return Filters
17. Pilot Pressure Filter
18. Pilot Pressure Valve
19. Double Tilt /Pitch Solenoid Valve
20. Blade Double Tilt/Pitch Cylinder
21. Pin Puller Valve
22. Pin Puller Cylinder
A. Oil Supply from Pressure Regulator Valve M Port Located at Steering Valve
B. Drain to Rear Frame
8. If ripper cylinders drift is more than 16 [mm] per minute and blade cylinders drift is more than
18 [mm] per minute lower the blade and ripper and follow below mentioned procedure. Refer to
HYDRAULIC CHART Fig. 10.10.
9. Plug blade pilot control valve (6) at point P. If cylinders drift is much less than checked in point
4 or 7, blade pilot control valve is faulty. Repair or replace the valve. Refer to BLADE PILOT
CONTROL VALVE in SECTION 10B. If cylinders drift is still the same proceed to next point.
10. Plug ripper pilot control valve (7) at point P. If cylinders drift is much less than checked in point
4 or 7, ripper pilot control valve is faulty. Repair or replace the valve. Refer to RIPPER PILOT
CONTROL VALVE in SECTION 10B. If cylinders drift is still the same, pilot pressure valve is
faulty. Repair or replace the valve. Refer to PILOT PRESSURE VALVE in SECTION 10B.
11. When proceeding tests are completed, vent hydraulic system and add oil as necessary. Refer
to the OPERATOR’S MANUAL. Visually check for oil leakage.
7B. RIPPER LIFT CYLINDERS DRIFT TEST
/BLADE LIFT CYLINDERS ARE NOT DROPPING/
There are two places that might be a source of leakage; one of hydraulic cylinder could leak post
piston packing and second of control valve could leak at its spool.
Following is a test to trace the source of internal leakage.
1. Raise and lower ripper and blade through its full travel. Oil temperature should be 82 - 88 [°C].
2. Lower the blade to the ground.
3. Fully lower the ripper to raise the rear of machine up.
4. Slightly move the lever to LOWER position releasing it to HOLD before machine drops to
ground.
5. Perform ripper lift cylinders drift test. Check cylinders for drift, rods should travel out of cylinders
no more than 16 [mm] per minute.
6. If ripper cylinders drift is less than 16 [mm] per minute one of cylinders is leaking. Proceed to
PISTON PACKING TEST in this SECTION to find which one is foulty.
7. If ripper cylinders drift is more than 16 [mm] per minute control valve spool is leaking. Proceed to
CONTROL VALVE in SECTION 10B.
8. When proceeding tests are completed, vent hydraulic system and add oil as necessary. Refer to
the OPERATOR’S MANUAL. Visually check for oil leakage.
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