DRESSTA TD-25M EXTRA, Service Manual

Page: 354 / 595

SECTION 10
HYDRAULICS
Page 12
TD-25M EXTRA DRESSTA
TEST AND ADJUSTMENT
This machine is provided with three control valve pressure relief valves, one in tilt (tilt/pitch) control
valve, one in blade lift and ripper control valve and one in pilot pressure valve. Tilt relief testing and
adjustment must proceed lift and ripper relief valve adjustment in order to obtain correct pressures
Pressure checks should be performed with oil at operating temperature. To bring temperature up,
move equipment control lever through all positions and bottom cylinders for a few seconds in each
position.
NOTE: Bottoming a cylinder for a short period of time will not damage hydraulic system; but
an extended period will produce excessive heat and result in quick oil deterioration.
Blade Tilt (Tilt/Pitch) Relief Valve Pressure Test
1. Open the door from right side and connect an 40 [MPa] gauge with quick coupler (see SERVICE
/SPECIAL TOOLS in this Section) to the quick disconnect fitting (3, Fig. 10.7).
2. Once operating temperature is reached, run engine at high idle and slowly move tilt lever into
a power position until cylinder is in an extreme position. Read and record pressure on test
gauge at which relief valve unloads. Repeat with engine at low idle. Obtained pressures should
range from 18350 tro 19100 [kPa]; if not proceed as follows:
If both low and high idle readings are similar but not as specified, system is operating correctly
but relief valve must be adjusted. Refer to Step 3.
If relief pressure is within 18350 - 19100 [kPa] at high idle but cannot be reached at low idle,
refer to Paragraph 10, PRESSURE DIAGNOSTIC CHART in this SECTON.
3. Remove acorn nut (1, Fig. 10.8) and outer seal washer (3) of relief valve. Loosen jam nut (9)
and turn adjusting screw (10) clockwise to increase pressure or counterclockwise to decrease
pressure. After correct pressure is obtained, retighten jam nut (9) while holding adjusting screw
(10) from turning. Install acorn nut (1) with outer seal washer (3). Recheck oil pressure.
4. Remove test gauge from the quick disconnect fitting and close the door from right side.
Fig. 10.8. Tilt Relief Valve
1. Acorn Nut
2. End Cap
3. Seal Washer
4. O-Ring 5. Pilot Poppet Spring
6. O-Ring
7. Main Poppet Spring
8. O-Ring 9. Jam Nut
10. Adjusting Screw
11. End Cap
12. Pilot Poppet 13. Pilot Popper Seat
14. Main Poppet
15. Main Poppet Seat