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GROUP 3 OPERATIONAL CHECKS AND TROUBLESHOOTING GROUP 3 OPERATIONAL CHECKS AND TROUBLESHOOTING 1. OPERATIONAL CHECKS 1. OPERATIONAL CHECKS This procedure is designed so the mechanic can make a quick check of the system using a minimum amount of diagnostic equipment. If you need additional information, read structure and function, Group 2. A location will be required which is level and has adequate space to complete the checks. The engine and all other major components must be at operating temperature for some checks. Locate system check in the left column and read completely, following the sequence from left to right. Read each check completely before performing.

At the end of each check, if no problem is found (OK), that check is complete or an additional check is needed. If problem is indicated (NOT OK), you will be given repair required and group location. If verification is needed, you will be given next best source of information: · Chapter 2 : Troubleshooting · Group 4 : Tests and adjustments 5-15

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Hydraulic oil must be at operating temperature for these checks. 5-16 Item Description Service action Hydraulic system warm-up procedure Run engine at high idle. Refer to page 5-33. Hold a hydraulic function over relief to heat oil (don't keep relief condition over 5 seconds at a time). Periodically cycle all hydraulic functions to distribute warm oil. Repeat procedure until oil is at operating temperature. FEEL : Hydraulic reservoir must be uncomfortable to hold your hand against. (approximately 40 ~50˚C) OK Check completed. Hydraulic pump performance check Heat hydraulic oil to operating temperature. Run engine at high idle. With bucket flat on ground, actuate boom raise.

Time how long it takes to raise boom to full height. LOOK : Boom must raise to full height in less than 7 seconds. OK Check completed. NOT OK Check the hydraulic pump. IF OK Do steering system leakage check at page 4-26. IF OK Do main hydraulic pump flow test at page 5-28. Control valve lift check Run machine at low idle. With bucket partially dumped, lower boom to raise front of machine. Slowly move boom control lever to boom lower position. Slowly move bucket control lever to bucket dump position. LOOK : Boom must not raise before moving down. Bucket must not rollback before dumping. OK Check complete. NOT OK Repair lift checks in loader control valve.

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5-17 Item Description Service action Bucket rollback circuit relief valve check Position bucket at a 45˚ angle against an immovable object. Engage transmission in 2nd speed forward. LOOK : Bucket angle must not change. OK Check complete. NOT OK Replace boom lower check valve. Bucket dump circuit relief valve low pressure check Raise front of machine which bucket at 45˚ angle. Backdrag with bucket while observing bucket angle. LOOK : Bucket must not rollback OK Go to next check. NOT OK Do loader system and circuit relief valve test at page 5-29. Boom cylinder and bucket cylinder drift check Heat hydraulic oil to operating temperature. Set the boom and bucket horizontal, then stop the engine.

Stop the engine, wait for 5 minutes, then start measuring. B Measure the amount the lift and dump cylinder rods retract during A 5 minutes. (unloaded bucket) A : Retraction of boom cylinder rod B : Retraction of bucket cylinder rod Boom cylinder must drift less than 4 mm Bucket cylinder must drift less than 6 mm OK Check complete. NOT OK Go to next check.

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5-18 Item Description Service action Boom cylinder leakage check Heat hydraulic oil to operating temperature. Dump bucket until teeth or cutting edge is perpendicular to the ground. Raise boom until cutting edge is about 1 m (3 ft) above ground. Stop engine. Measure drift from tooth or cutting edge to ground for 1 minute. Wait 10 minutes. Measure drift from tooth or cutting edge to ground for 1 minute. LOOK : Compare the drift rate between the first measurement and the second measurement. OK Drift is approximately the same between first and second measurement. Repair loader control valve or circuit relief valve. NOT OK If drift is considerably less on second measurement, repair cylinder.

Bucket cylinder leakage check Heat hydraulic oil to operating temperature. Raise bucket about 1 m (3 ft) off ground with bucket level. Stop engine. Place a support under boom. Measure drift from tooth or cutting edge to ground for 1 minute. Wait 10 minutes. Measure drift from tooth or cutting edge to ground for 1 minute. LOOK : Compare the drift rates between the first measurement and the second measurement. OK Drift is approximately the same between first and second measurement. Repair loader control valve or circuit relief valve at page 5-34. NOT OK Drift is considerably less on second measurement. Repair cylinder.

Check valve of safety valve leakage check Heat hydraulic oil to operating temperature. Put bucket level and position about 1.2 m (4 ft) above ground. Place a piece of tape on cylinder rod at least 51 mm (2 in) from rod guide. Run engine at low idle in safety- release position. LOOK : Bucket must not drift up. OK Check complete. NOT OK Check or replace safety valve. Control lever check Stop engine. Turn key switch to OFF position. Move bucket control lever to roll back, dump positions and then release. LOOK : Lever must return to neutral when released from roll back, dump positions. OK Check completed. NOT OK Repair bucket control lever.

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