In Combined Operation Of Work Equipment Or Swing And Travel, Travel Speed Drops Largely - Komatsu PC88MR-10 Shop Manual

H-19 In combined operation of work equipment or swing and travel,
travel speed drops largely

In combined operation of work equipment or swing and travel, travel speed drops largely.

Failure
Perform all troubleshooting with working mode set in power (P) mode.
Related
Before performing troubleshooting, check that the hydraulic oil level tank is normal.
information
Hydraulic oil temperature: 45 to 55°C
No. Cause
Malfunction of pump
1 merge-divider solenoid
valve
Malfunction of merge-
2
divider main spool
Malfunction of boom
control valve (pressure
3
compensation valve)
(boom RAISE side)
Malfunction of boom
control valve (pressure
4
compensation valve)
(boom LOWER side)
Malfunction of arm
control valve (pressure
5
compensation valve)
(arm IN side)
Malfunction of arm
control valve (pressure
6
compensation valve)
(arm OUT side)
Malfunction of bucket
control valve (pressure
7
compensation valve)
(bucket CURL side)
Malfunction of bucket
control valve (pressure
8
compensation valve)
(bucket DUMP side)
PC88MR-10
Troubleshooting of hydraulic and mechanical system (H-
(PC88MR-D26-400-A-Z0-A)
Procedure, measuring location, criteria, and remarks
a Be ready with engine stopped, then perform troubleshooting with engine at
high idle.
Work equipment control lever is in
Main EPC output
pressure
a Release remaining pressure from hydraulic tank and piping, and then
perform troubleshooting with engine stopped.
Check for stuck or seized main spool in merge-divider valve body.
(It must be moved smoothly and must not be caught.)
Remove main spool from valve body and check it for defects and dirt.
Be careful to prevent foreign matter from entering into it when re-installing
spool.
a Check whether boom cylinder moves slowly to RAISE side when
performing hydraulic relief of other work equipment. (If boom cylinder
moves, it is abnormal.)
a If any failure is found in above check item, interchange pressure
compensation valves between both ports, and check whether failure
symptom changes.
(Each area ratio is different, so be sure to restore it after checking the
symptom.)
a Check whether boom cylinder moves slowly to LOWER side when
performing hydraulic relief of other work equipment. (If boom cylinder
moves, it is abnormal.)
a Check whether arm cylinder moves slowly to arm IN side when performing
hydraulic relief of other work equipment. (If arm cylinder moves, it is
abnormal.)
a Check whether arm cylinder moves slowly to arm OUT side when
performing hydraulic relief of other work equipment. (If arm cylinder moves,
it is abnormal.)
a Check whether bucket cylinder moves slowly to bucket CURL side when
performing hydraulic relief of other work equipment. (If bucket cylinder
moves, it is abnormal.)
a Check whether bucket cylinder moves slowly to bucket DUMP side when
performing hydraulic relief of other work equipment. (If bucket cylinder
moves, it is abnormal.)
neutral
Bucket CURL and Arm IN
40 Troubleshooting
mode)
0 MPa {0 kg/cm 2 }
3.14 ± 0.5 MPa
{32 ± 5 kg/cm 2 }
40-491