jcb JS 200 Series, Service Manual

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5 - 5
Sectyion F
Transmission
9803/6400
Section F
5 - 5
Issue 2*
Motor/Gearbox
Fault Finding (continued)
2-Speed Control Function
Fault Possible cause Countermeasure or remedy
1. Travel is not linear 1. Plunger is not switched
1) Foreign matter is caught between Completely remove foreign matter, repair
plunger and body. the damage and reassemble after cleaning.
Replace if damage or leakage is excessive.
2) Spring is not assembled correctly. Assemble spring in specified position.
3) Spring is broken. Renew spring.
4) Foreign matter is trapped in spool Completely remove foreign matter, repair
galleries. the damage and reassemble after cleaning.
Replace if damage or leakage is large.
2. Pressurised oil leaks due to abnormal Replace the 2-speed control piston.
wear of 2-speed control piston Completely remove foreign matter and
reassemble after cleaning.
3. 2-speed control piston is not assembled Assemble 2-speed control piston to the
correctly specified position.
4. Steel ball is abnormally worn. Replace steel balls. Completely remove
foreign matter and reassemble after cleaning.
5. Set pressure is rising due to Replace spool. Completely remove
abnormal wear of spools. foreign matter and reassemble after cleaning.
6. The orifice of the 2-speed piston cavity Confirm orifice diameter.
drain is incorrect.
7. The orifice of the 2-speed piston cavity Reassemble after cleaning.
drain is clogged.
8. Number of washers is different and set Reassemble using correct number of washers.
pressure is different on the left and right.
2.Will not go into 2nd. 1. Plunger is not switched
1) Foreign matter is caught between Completely remove foreign matter, repair the
plunger and body. damage and reassemble after cleaning.
Replace if damage or leakage is excessive.
2) Foreign matter is trapped in spool Completely remove foreign matter, repair
galleries. the damage and reassemble after cleaning.
Replace if damage or leakage is excessive.
2. Pressurised oil leaks due to abnormal Replace the 2-speed control piston.
wear of 2-speed control piston. Completely remove foreign matter and
reassemble after cleaning.
3. 2-speed control piston is not assembled Assemble 2-speed control piston to the
correctly. specified position.
4. The orifice of the 2-speed piston cavity Reassemble after cleaning.
drain is clogged.
3.Will not go into 1st. 1. Spring is not assembled correctly. Assemble spring to specified position.
2. Spring is broken. Replace spring. Completely remove foreign
matter, repair the damage and reassemble after
cleaning. Replace if the damage or leakage
is excessive.
3. Set pressure is rising due to abnormal Replace spool. Completely remove
wear of spools. foreign matter, repair the damage and
reassemble after cleaning. Replace if the
damage or leakage is excessive.
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