VOLVO BM L90B and L120B Wheel Loader Service Manual

VOLVO BM L90B and L120B Wheel Loader Service Manual

This in-depth factory service manual provides professional-grade maintenance and repair procedures for the VOLVO BM L90B and L120B Wheel Loaders. Designed for technicians and mechanical specialists, it covers articulated steering systems, turbocharged diesel engines, hydraulic transmissions, brake circuits, electrical layouts, and advanced shifting systems (APS).

Model Covers:

Volvo BM L90B – TD61G Engine
Volvo BM L120B – TD71G Engine

File Format: PDF

Size: 38.61 MB

No. of pages: 689

Language: English

Delivery Method: Instant Download – Access your file immediately after purchase.

📑 Table of Contents Overview:

Engine & Transmission Systems

• Six-cylinder, turbocharged diesel engines (TD61G & TD71G) with direct injection
• Hydro-mechanical constant mesh transmission with single-stage torque converter (HT131)
• Automatic Power Shift (APS) function via Contronic ECU for smooth gear transitions and engine braking

Hydraulic & Steering Systems

• Load-sensing axial-piston pumps with variable flow for working hydraulics and steering
• Articulated frame hydrostatic steering with ORBITROL valve and optional CDC lever steering
• Secondary electric steering system with flow sensors, ECU-controlled diagnostics and emergency override

Braking System

• Dual-circuit all-hydraulic disc brakes with four-piston calipers per axle
• Separate accumulators for each circuit, precharged with nitrogen for consistent pressure
• Brake pressure monitoring with warning lamps and low-pressure alerts via control panel display

Electrical System & ECU Integration

• 24V electrical system with dual 12V batteries (140 Ah/105 Ah depending on model)
• Centralized electrical distribution box with fuses, relays, and Contronic Electronic Control Unit (ECU)
• Systematic cable marking and diagnostic points for efficient troubleshooting

Pumps & Flow Control

• Nine-cylinder axial piston pumps with adjustable yoke angle for flow modulation
• Sensor-driven flow and pressure differential control to regulate secondary steering activation
• Valve logic responsive to pressure deltas and machine speed for system redundancy

This detailed VOLVO BM L90B and L120B Wheel Loader Service Manual is your essential guide for diagnostic, hydraulic, drivetrain, and operational servicing.