H-2 The Travel Speed Is Slow - Komatsu WA250-6 Shop Manual

500 Troubleshooting of hydraulic and mechanical system (H-mode)

H-2 The travel speed is slow

H-2 The travel speed is slow
Ask the operator about the following:
Did the travel speed suddenly become
q
slower?
o Breakage of HST pump and motor
related equipment
Was there any problem of travel speed
q
becoming slower before?
o Internal wear of HST pump and
motor related equipment, defective
seal
Inspection before diagnosis
Are the oil level in the hydraulic tank and
q
the oil type appropriate?
Is the inching valve linkage adjusting
q
appropriate?
Is the any external oil leak found around
q
the hydraulic piping, pump and motor?
No.
Diagnosis
1 Travel speed is slow in both forward and reverse
The travel speed is slow at forward (Reverse is nor-
2
mal)
The travel speed is slow at reverse (Forward is nor-
3
mal)
Maximum travel speed in both forward and reverse
4
is approx. 4 km/h
Maximum travel speed in both forward and reverse
5
is approx. 18 km/h
Abnormal sound comes from motor in both forward
6
and reverse when travel speed is 10 km/h or more
WA250, 250PZ-6
HST pump
a b c d
E E E E
Remedy
X X X X
Q Q Q
Q
Q
Cause
HST
HST motor 2
motor 1
e f g h i j
E E E E E E
X X X X X X
Q Q Q Q Q
Q
Q
Q
SEN03849-00
1
Others
k l m n o
E E E E E
X X X X X
A
Q Q Q Q Q
Q
Q Q
9
40-500