Komatsu PC20R-8 Shop Manual page 174

TESTING AND ADJUSTMENTS
5. Blade test
1 - Position the machine with the arm resting verti-
cally on the ground and with the bucket resting
on its back.
2 - Raise the blade completely and support it on a
centrally-positioned block.
3 - Stop the engine and release the residual hydrau-
lic pressures.
4 - Disconnect the hoses (1) and (2) of the blade cy-
linder (3) and plug them.
5 - Plug the hole of the blade cylinder on the head
side and attach a provisional tube on the base
side to catch any oil leakages.
6 - Start the engine and force the boom down to
raise the machine in order to remove the block
on which the blade is resting.
7 - Lower the blade and stop the engine.
8 - Check the position of the blade for 15 minutes.
If the blade moves downwards the drift is due
.
to the cylinder.
If the blade does not move downwards, the
.
drift is due to the safety valve.
H In order to check whether the drift is due to the
swivel joint, see: «CHECKING LEAKAGES IN-
SIDE THE SWIVEL JOINT».
6. Swing motor test
1 - Position the machine with boom, arm and bucket
raised as in the figure and with the revolving
frame turned 135ë to the left.
2 - Stop the engine and release the residual hydrau-
lic pressures.
20-58
CONTROL OF HYDRAULIC DRIFTS -
ANALYSIS OF THE CAUSES OF A DRIFT
2
RKP04930
1
3
RKPA2520
RKP04980
PC20R-8 PC27R-8