Komatsu's own document number, WEBM008601, is printed on the cover of this Komatsu PC80MR-3 shop manual PDF, the 302-page factory book written for that hydraulic excavator. Hydraulic circuit and electrical diagrams close out the book, the hydraulic sheet tracing oil from the pump group through the control valve, while the largest share of pages goes to disassembly and assembly of the injection pump, engine head, swing motor and reduction gear, and swivel joint. Before you split anything, Testing and Adjusting walks you through engine speed measurement, exhaust smoke colour, and pinning down the cause of hydraulic drift. Check the track frame idler guide against its 74 mm basic width and 78 mm limit, and fill the final drive with SAE 85W-90. Guess a figure and you pay for the second teardown. Bookmarks and a live text layer take you straight to the right procedure, and your PC80MR-3 is swinging a bucket again before the crew loses another shift.
What's Inside This Komatsu PC80MR-3 Manual
| System | Pages | Key Topics |
|---|---|---|
| Structure and Function | 27-108 | Power Train, Swing Machinery, Track Frame and Idler Cushion, Control Valve |
| Testing and Adjusting | 109-174 | Normal or Standard Technical Data, Measuring the Engine Speed, Checking the Exhaust Smoke Colour, Analysis of the Causes of Hydraulic Drifts |
| Disassembly and Assembly | 175-294 | Counterweight, Injection Pump, Engine Head, Pump Group, Engine Pumps, Complete Radiator and Air Conditioning Condenser, Swing Motor and Reduction Gear, Swivel Joint |
| Other | 295-302 | Hydraulic Circuit, Electrical Diagram |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Final drive oil viscosity | SAE 85W-90 | p. 17 |
| Tightening torque for nuts of flared (1/2" - 20) | 2.6±0.5 kgm (25.5±4.9 Nm) | p. 13 |
| Tightening torque for nuts of flared (9/16" - 18) | 4±0.5 kgm (39.2±4.9 Nm) | p. 13 |
| Vertical width of idler guide (Track frame) | 74 mm (Basic dimension), 78 mm (Limit size) | p. 35 |
| Vertical width of idler guide (Idler support) | 73 mm (Basic dimension), 69 mm (Limit size) | p. 35 |
| Travel motor change displacement pressure | 32 bar | p. 46 |
| Travel motor min. pressure opening brake | 13 bar | p. 46 |
| Tightening torque of cylinder head (Boom) | 961 ± 96.1 Nm | p. 51 |
| Tightening torque of cylinder head (Boom swing) | 785 ± 78.5 Nm | p. 51 |
| General valve P1 (boom – arm - bucket) - Boom swing and travel | 256 – 275 bar | p. 113 |
| Main valve P2 (Blade - Swing) | 201 – 215 bar | p. 113 |
| Engine High Idling Speed | 2250 +100/-50 rpm | p. 111 |
Komatsu PC80MR-3 Common Problems This Manual Covers
Komatsu PC80MR-3 boom, arm, blade and swing functions weak with hydraulic pressure dropping on the test gauge
Lower the equipment to the ground and stop the engine, slowly loosen the tank cap to relieve pressure, and move the safety engagement lever to the locked position. Measure P1 general valve pressure and compare it against the standard value on page 113, 256 to 275 bar for boom, arm, bucket, boom swing and travel. Check P2 blade and swing at 201 to 215 bar. If P2 is low, adjust the general valve following page 146 (about 120 bar per screw turn) and torque the lock nut to 39 to 49 Nm.
Manual Section: Hydraulic System Troubleshooting p. 113Boom, arm or bucket cylinder leaking internally and drifting down with the controls in neutral
Remove and connect tubes only after relieving residual pressures. Test boom, arm and bucket drift following the hydraulic drift analysis to confirm which cylinder is leaking. Overhaul the leaking cylinder, then torque the boom cylinder head to 961 ± 96.1 Nm following page 51. For the bucket cylinder head, use the three stage sequence on page 276 at 116 to 142 daNm.
Manual Section: Hydraulic Drift AnalysisSwing motor leaking internally with the revolving frame slow to start swing and drifting
Lower the equipment to the ground, stop the engine and operate the PPC valves several times. Check swing start time and revolving frame drift following the swing tests: start time on page 113 and revolving frame mechanical drift on page 114. Measure the revolving frame secondary valve against 196 to 201 bar, then verify swing motor brake solenoid output at 32 ± 5 bar on page 153. If both read correct, test the swing motor for internal leakage before pulling it.
Manual Section: Swing System Troubleshooting p. 113Travel motor leaking internally with the machine deviating to one side and travel speed dropping
Ensure that the block used to hold the track up is strong enough not to be ejected out. Measure travel speed and travel deviation using the travel system tests, then test each travel motor for hydraulic drift and inner leakage. Verify the travel speed selector solenoid output at 32 ± 5 bar on page 153. Check the displacement change at 32 bar and brake opening at 13 bar minimum following page 46.
Manual Section: Travel System TroubleshootingEngine not reaching high idle with off-colour exhaust smoke and low oil pressure
When measuring compression, keep body and clothing clear of the cooling fan, alternator belt and other rotating parts. Measure engine speed following page 127 against 2250 +100/-50 rpm at high idle and 1100 ± 50 rpm at low idle. Check exhaust smoke colour, then verify that oil pressure at high idle with SAE 30 reads 3.5 to 5.5 kg/cm². If the oil pressure or smoke is still off, test compression and blow-by pressure before you open up the engine.
Manual Section: Engine Troubleshooting p. 127Idler, track rollers and sprocket worn down to the limit size on tread and root diameters
Measure idler tread diameter against Ø 415 mm basic and Ø 407 mm limit following page 36. Check track rollers against the Ø 103 mm limit on page 37 and carrier rollers against Ø 72 mm on page 38. Replace the sprocket when root diameter reaches Ø 421 mm or tip diameter reaches Ø 472 mm per page 39.
Manual Section: Structure and Function p. 36Frequently Asked Questions
What is the correct final-drive oil and viscosity for a PC80MR-3?
The correct oil for the travel reduction gear is API GL5 oil. The capacity for the travel reduction gear is 2.7 liters for the first filling and 2.7 liters for a change, and the separate final drive takes 1.3 liters for the first filling and 1.3 liters for a change. p. 17
What is the standard tightening torque for a 14mm bolt on the Komatsu PC80MR-3?
The standard tightening torque for a 14mm bolt with a 2mm pitch is 12.5 ± 1 kgm (122 ± 13 Nm) for an 8.8 grade bolt, and 17.5 ± 2 kgm (172 ± 18 Nm) for a 10.9 grade bolt. p. 12
What is the procedure for adjusting the boom safety valve?
To adjust the boom safety valve, maintain maximum pressure and adjust the screw (13) until a slight leakage of oil (a few drops per minute) is seen at flange V2. Each turn of the screw changes the pressure by 110 bar. p. 154
What is the engine oil capacity for the PC80MR-3?
The engine oil pan capacity for the PC80MR-3 is 9.8 liters for the first filling and 9.4 liters for an oil change. p. 17
How will I receive this Komatsu PC80MR-3 Shop Manual?
Immediate download of the complete 302-page searchable Shop Manual. Access it on any device, from a laptop at your desk to a phone in the field.
Is this Komatsu PC80MR-3 manual print-friendly?
You can. Print the sections you want for your own use and keep the file as your backup.
Does this Komatsu PC80MR-3 Shop Manual cover the hydraulic system?
Yes. The manual includes hydraulic circuit diagrams, system schematics, and component specifications with pressure ratings. You can see one on page 297.
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