1997-2002 Hyundai Robex 55-3 R55-3 Crawler Excavator Factory Service Manual (P/N R55NM2SP08)

• Covers 1997–2002 Hyundai Robex 55-3 and R55-3 crawler excavators. Documents service and repair requirements for the Yanmar 4TNE94 engine, hydraulic systems, and undercarriage variants.
• Original OEM publication (code R55NM2SP08) detailing specifications, assembly, and testing procedures.
• Features 64 detailed hydraulic circuit diagrams, component location maps, torque-specification tables, and pressure-testing charts.
• Comprehensive 329-page technical reference. Provides component-weight data for major assemblies like the 2,475 kg upperstructure and 2,305 kg lower chassis.
• Serves as the primary reference for the R55-3 model series. It clearly documents the transition from mechanical to pilot-operated control valve systems after serial number #0580.

Structural and Hydraulic Walkthrough

The documentation delivers a deep technical overview of the machine architecture. Section 1 outlines general machine specifications, detailing lifting capacities and bucket selection guides. Heavy machinery operations carry inherent risks. Always adhere strictly to the documented safety protocols before initiating any service procedures. Section 2 breaks down the structure and function of the hydraulic circuit. It examines the main control valve, pump assembly, swing machinery, and travel device. The text smoothly transitions from operational theory—such as the P1+P2=constant pump output control—directly into component-level structure. Practitioners will appreciate the clear, industry-standard terminology.

Sections 4 through 7 offer extensive information regarding the electrical system, hydraulic component repair diagnostics, and maintenance standards. Disassembly and assembly documentation is laid out for all major modules, including the travel motor, swing motor, and turning joint. The text provides a rigorous look at machine upkeep. You will find precise filter change intervals and hydraulic oil preheating requirements designed for cold-weather operation.

Technical Data and Maintenance Specifications

This manual provides reliable data benchmarks for verifying machine performance. Low idle speed is specified at 1,100 ± 50 rpm. High idle is set at 2,560 ± 50 rpm. Engine oil capacity is documented at 9.7 liters (2.6 U.S. gal). The main relief valve pressure reaches 210 kg/cm² (2,987 psi), with overload relief valves documented at 230 kg/cm² (3,271 psi). For optimal operation, the track gauge measures 1,445 mm.

Service intervals for the hydraulic filter are specified at 500-hour increments. Initial checks are required during the first week of operation. Boom cylinder bore, rod, and stroke dimensions measure precisely 100 mm x 55 mm x 636 mm. This exactness proves essential when assessing machine wear, as evidenced by the 4.0 mm/hr standard wear tolerance for boom cylinder pin bushings.