Built for one machine, the Kobelco SK50SR-3 hydraulic excavator, this Kobelco SK50SR-3 service manual PDF runs 754 pages under factory publication number S5PJ0009E-01. Hydraulic circuit operation gets a long chapter of its own, tracing the travel and bucket circuits, while disassembly and assembly procedures fill roughly a third of the book. Near the back, hydraulic and electric circuit diagrams let you follow a line from pump to cylinder or from key switch to starter, and the troubleshooting section splits hydraulic faults from electrical ones, with the engine getting its own chapter on inspection, adjustment and diagnosis. Check your engine work against a four-cylinder, 88 x 90 mm bore and stroke rated at 30.4 kW at 2,400 min⁻¹, and torque a 1/8 PF O-ring pipe joint to 17 ± 2 N·m. A travel fault with no circuit diagram can eat a whole shift. Print what the job calls for and let it get greasy at the bench; the bookmarked, text-searchable original stays clean.
What's Inside This Kobelco SK50SR-3 Manual
| System | Pages | Key Topics |
|---|---|---|
| Outline | 10-17 | General Precautions for Repairs |
| Specifications | 18-29 | Machine Dimensions, Machine and Components Weight, Engine Specifications |
| Installation Procedures for Optional Attachment | 30-65 | Boom Dimensional Drawings, Arm Dimensional Drawings, Bucket Dimensional Drawings |
| Maintenance | 66-95 | Standard Working Time Table |
| System | 96-235 | Hydraulic Circuit Operation, Travel Operating Circuit, Bucket Operating Circuit |
| Disassembling | 236-485 | General Disassembly and Assembly |
| Troubleshooting | 486-519 | Trouble Diagnosis Hydraulic, Troubleshooting Hydraulic System, Troubleshooting Electrical System |
| Engine | 520-735 | Engine Specifications, Inspection and Adjustment, Troubleshooting Engine |
| Supporting Data | 736-754 | Hydraulic Circuit Diagram, Electric Circuit Diagram |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Metric Coarse Thread Standard Tightening Torque (M6, 4.8T, No lubrication) | 4.4 ± 0.5 N·m | p. 56 |
| Metric Coarse Thread Standard Tightening Torque (M27, 10.9T, Oil lubrication) | 1370 ± 137 N·m | p. 56 |
| Return Filter | Safety valve containing/Filter Type (30μ) | p. 22 |
| Joints for Piping (O-ring sealing type) Tightening torque (1/8 PF) | 17 ± 2 N·m | p. 58 |
| Number of cylinders-Bore x Stroke | 4 - 88 mm x 90 mm (3.46 in x 3.54 in) | p. 27 |
| Total Displacement | 2.189 L (134 cu·in) | p. 22 |
| Travel motor rated output torque (1st / 2nd) | 5710 / 3280 N·m (4211 / 1033 lb·ft) | p. 198 |
| Travel motor rated operating pressure | 23.0 MPa (3340 psi) | p. 198 |
| Link pitch (Reference value) | 135 mm (5.32 in) | p. 416 |
| Link pitch (Repairable level) | 139 mm (5.47 in) | p. 416 |
| Tightening torque of capscrews (2) for lower roller | 280 N·m (207 lbf·ft) | p. 423 |
| Tightening torque of grease nipple for crawler adjuster | 73.5 N·m (54.2 lbf·ft) | p. 423 |
Kobelco SK50SR-3 Common Problems This Manual Covers
Kobelco SK50SR-3 travel motor loses travel power, runs slow, or machine deviates to one side while traveling
Measure pilot pump delivery pressure first following page 492; it must read 35.5 kgf/cm² (505 psi) or over. Then check travel motor relief pressure against 23.0 +0.5 MPa listed on page 80. If both are in spec, work through the travel speed and deviation charts before pulling the motor.
Manual Section: Travel Motor Troubleshooting p. 492Undercarriage track chain sagging loose with stretched link pitch and worn link bushings
Measure iron crawler slack and set it within 130 to 150 mm per page 416. Check link pitch against the 143 mm service limit and link height against the 62 mm limit. Measure bushing O.D. against the 31 mm service limit on page 422 before deciding to repair the chain.
Manual Section: Disassembling p. 416Travel motor sprocket teeth worn thin or sprocket capscrews working loose on the undercarriage
Measure sprocket tooth width against the 32 mm standard on page 439; repairable level is 29 mm and service limit 27 mm. Check O.D. against the 427 mm limit. When refitting, torque sprocket capscrews to 181 N·m (133 lbf·ft) and travel motor fixing capscrews to the same value per page 440.
Manual Section: Disassembling p. 439Slewing motor not slewing, insufficient torque, abnormal noise, or time-lag when starting a swing
Inspect the slewing motor for oil leaks and abnormal heat before anything else, then note whether the fault is no slew, weak torque, noise or time-lag. Work the Slewing Motor Troubleshooting chart by that symptom. While you are in there, grease the slewing bearing with approx. 90 g (3.2 oz) per page 444.
Manual Section: Slewing Motor TroubleshootingAttachment cylinder drifts down on its own or moves in reverse through the control valve
Check pump relief pressure at P1 and P2 against 23.0 +0.5 MPa per page 80 before blaming the cylinder. If pressure holds, inspect the control valve for the natural drop and reverse movement causes in the Control Valve Troubleshooting chart. Torque any disturbed O-ring piping joints to the values on page 58.
Manual Section: Control Valve TroubleshootingEngine output drops with excessive exhaust smoke and higher than normal fuel consumption
Test fuel injection nozzle opening pressure against 19.6 to 20.6 MPa per page 580. Measure valve clearance and adjust to 0.15 to 0.25 mm following page 724. If the head comes off, torque cylinder head bolts to 85.3 to 91.1 N·m per page 733. Then rerun the output checks in Engine Troubleshooting.
Manual Section: Engine p. 580Frequently Asked Questions
What are the replacement specifications for the lower roller on the Kobelco SK50SR-3?
The lower roller assembly should be replaced if the wear on the tread diameter exceeds the service limit of 92 mm (3.62 in) or if the flange width is less than 34 mm (1.34 in). p. 422
What are the sprocket replacement specifications for the Kobelco SK50SR-3?
The sprocket should be replaced if the width of the sprocket teeth is less than 27 mm (1.06 in) or if the outside diameter is less than 427 mm (16.8 in). p. 439
What is the cylinder head bolt tightening torque on the 3TNV82A engine in the Kobelco SK50SR-3?
The cylinder head bolts for the 3TNV82A engine must be tightened in two steps. The first step is 30.0-34.0 Nm (3.1-3.5 kgf-m) and the second step is 61.7-65.7 Nm (6.3-6.7 kgf-m). p. 611
What is the standard valve clearance for the 3TNV82A-98 engine on the Kobelco SK50SR-3?
The standard valve clearance for the 3TNV82A-98 engine is 0.15 to 0.25 mm. p. 614
What is the engine oil capacity for the 3TNV82A engine in the Kobelco SK50SR-3?
The total engine oil capacity for the 3TNV82A engine is 5.5 liters, with an effective capacity of 1.9 liters. p. 539
Do I get instant access to this Kobelco SK50SR-3 Service Manual?
Immediate download of the complete 754-page searchable Service Manual. Access it on any device, from a laptop at your desk to a phone in the field.
Can I print this Kobelco SK50SR-3 manual?
Printing is allowed without restriction. Pull the pages you need for the job and bin them when they get greasy.
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