DRESSTA TD-25M EXTRA, Service Manual, Page: 357 / 595

HYDRAULICS
SECTION 10
Page 15
DRESSTA TD-25M EXTRA
TEST AND ADJUSTMENT
NOTE: The 18 [mm] per minute figure represents the accumulative allowable loss of cylinders,
control valve and valves.
5. If cylinders drift is more than 18 [mm] per minute lower blade and follow below mentioned
procedure. Refer to HYDRAULIC CHART Fig. 10.10.
6. Fully lower the blade to raise the front side of machine up. Slightly move the lever to LOWER
position and release it to HOLD. Perform blade lift cylinders drift test. Check cylinders for drift.
If cylinders drift is much less than checked in point 4 the problem is inside of one blade
cylinder. Refer to PISTON PACKING TEST.
7. If cylinders drift is still the same plug the pilot pressure valve (18) at point PP . If cylinders drift is
much less than checked in point 4, 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.
8. Plug the pilot pressure valve (18) at point AI . If cylinders drift is much less than checked in
point 4, pilot pressure valve is faulty. Repair or replace the valve. Refer to PILOT PRESSURE
VALVE in SECTION 10B. If cylinders drift is still the same proceed to next point.
9. Raise the blade and support it on some bracket. Plug the one spool control valve in point “ a ”.
Go back with machine to free the blade. Stop the machine and check for drift. If cylinders
drift is much less than checked in point 4, control valve is faulty. Repair or replace the valve.
Refer to ONE SPOOL CONTROL VALVE in SECTION 10B. If cylinders drift is still the same,
the quick drop valve is faulty. Repair or replace the valve. Refer to QUICK DROP VALVE
in SECTION 10B.
10. When proceeding tests are completed, vent hydraulic system and add oil as necessary. Refer
to the OPERATOR’S MANUAL. Visually check for oil leakage.
7A. BLADE LIFT CYLINDERS AND RIPPER LIFT CYLINDERS DRIFT TEST
(MACHINE WITH RIPPER)
/BLADE AND RIPPER LIFT CYLINDERS ARE DROPPING/
There are three places that might be a source of leakage for both ripper and blade cylinders; pilot
pressure valve could leak, ripper pilot control valve could leak or blade pilot control valve could
leak.
Following is a series of tests 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 raise ripper and move lever to LOWER position releasing it to HOLD before ripper drops
to ground.
4. Perform ripper lift cylinders drift test. Check cylinders for drift, rods should travel out of cylinders
no more than 16 [mm] per minute.
5. Lower the ripper to the ground.
6. Fully raise the blade and move the blade lift lever to LOWER position releasing it to HOLD
before the blade drops to the ground
7. Perform blade lift cylinders drift test. Check cylinders for drift, rods should travel out of cylinders
no more then 18 [mm] per minute.