Job Name:

Dismantling and Assembling of Front and Rear Axles – A Comprehensive Study on Axle
Construction, Working Mechanism, and Type Identification

Objectives:

The main goal of this practical session is to gain in-depth theoretical and hands-on knowledge
regarding the construction and working principles of front and rear axle assemblies in an automobile.
This includes:

1. To methodically dismantle the front and rear axle assemblies of a vehicle to thoroughly study
their constructional elements and inner mechanisms.

2. To individually identify and understand the function of each component that makes up both
the front and rear axles, including shafts, hubs, bearings, differential gears, and housing
units.

3. To recognize the different types of axles (dead/live, full-floating/semi-floating/three-quarter

floating) based on their construction and functionality.

4. To observe the load transmission, torque distribution, and wheel rotation mechanics that
take place through axle systems.

5. To reassemble the axle system correctly using appropriate tools and techniques while
ensuring all torque specifications, alignments, and lubrication standards are strictly adhered
to.

6. To examine the materials and surface treatments applied to various axle parts for durability,
strength, and corrosion resistance.

7. To develop essential technical and diagnostic skills useful in vehicle repair, inspection, and
maintenance.

Tools and Equipment Used:

To perform the dismantling and assembling process effectively, a variety of professional-grade

automotive tools and diagnostic instruments were used, including:

• Hydraulic Jack and Axle Stands (for lifting and stabilizing the vehicle)

• Complete Spanner Set and Socket Wrench Set (for loosening and tightening fasteners)

• Torque Wrench (to ensure accurate reassembly torque values)

• Pullers and Hammer (for removing bearings and hubs)

• Screwdrivers, Pliers, and Circlip Removers

• Cleaning Brushes and Degreasing Solvents

• Micrometers and Vernier Calipers (for dimensional checks)

 • Grease Gun and High-Temperature Bearing Grease

Detailed Observations:

Front Axle Assembly:

• Axle Type: Dead Axle (also known as a beam axle)

• Structural Configuration: The front axle is a rigid, non-driven type constructed using
hightensile solid steel. It includes two stub axles that are connected to the steering knuckles
and kingpins.

• Functionality: As it is not responsible for power transmission, it primarily supports the

vehicle’s front load and facilitates directional control through steering. It also plays a role in
absorbing road shocks in conjunction with the suspension system.

• Key Components: Kingpin, steering knuckle, stub axles, wheel hub, bearings, and brake
assembly.

• Additional Notes: This axle type is widely used in rear-wheel-drive (RWD) vehicles where
front wheels are not responsible for driving the vehicle.

Rear Axle Assembly:

• Axle Type: Live Axle – Semi-Floating Design

• Structural Configuration: The rear axle is a live axle, which means it transmits power from
the engine to the wheels. The semi-floating design supports both the vehicle weight and
torque to an extent but places more load on the axle shaft compared to a full-floating design.

• Functional Mechanism: The rear axle receives power via the propeller shaft from the
gearbox. The differential assembly splits the torque between the two wheels and allows
them to rotate at different speeds during turns.

• Key Components: Axle housing, axle shafts, differential gears (bevel/pinion), ring gear,
bearings, oil seals, brake assemblies, and wheel hubs.

• Observations on Wear: Minor wear was observed on the bearing surfaces, and gear teeth
showed signs of routine operational stress, but no severe damage or pitting was found.

Material and Heat Treatment Data:

Component Material Used Heat Treatment Process Purpose

SAE 1541 / EN24 Improves wear resistance and

Axle Shafts Induction Hardening
Steel surface hardness
Differential Carburizing followed by Enhances surface hardness with
8620 Alloy Steel
Gears Quenching a tough core

High Carbon High durability and fatigue

Bearings Case Hardening
Chromium Steel resistance

Powder Coating / Spray

Housing Mild Steel Corrosion protection
Painting
Tempering after
Kingpins and Hardened Steel Alloy Balance of strength and
Bushes Quenching toughness

Procedure:

1. The vehicle was securely lifted using a hydraulic jack and supported with axle stands.

2. The front axle was accessed by removing the wheels, brake components, and steering
linkages.

3. The kingpins and knuckles were carefully disassembled to remove stub axles and inspect
bushings and bearings.

4. For the rear axle, the propeller shaft was first disconnected, followed by draining the axle oil.

5. The differential cover was removed, allowing access to the ring gear and pinion assembly.

6. Axle shafts were extracted after detaching the wheel hubs and brake drums.

7. All components were thoroughly cleaned using degreasing agents.

8. Each part was inspected for signs of wear, deformation, or misalignment.

9. After inspection, all parts were reassembled in reverse order using proper torque
specifications.

10. Lubrication was applied wherever necessary, and the system was tested for smooth
operation.

Remarks:

• The axle dismantling and assembly process revealed a great deal of insight into mechanical
design and powertrain dynamics.

• The front axle, being a dead axle, involved relatively simpler construction and disassembly.

• The rear axle assembly, particularly the differential and semi-floating shaft configuration, was
more complex but essential for understanding torque transmission.

• Heat-treated and hardened components are critical for long-term durability, especially in
high-load conditions.

• Proper alignment during reassembly is essential to avoid noise, vibration, and uneven wear.
• The job reinforced the importance of preventive maintenance, especially inspecting bearings,
seals, and lubricants regularly to avoid costly breakdowns.