Heavy Steering

When turning the steering wheel requires noticeably more effort than usual, it typically indicates a fault or an abnormal load within the power steering system. Depending on whether your vehicle uses hydraulic or electric power steering, the diagnostic approach will differ.

Electric Power Steering (EPS) Models

This is the standard configuration found in most modern passenger cars.

Causes of Failure: 

Insufficient Battery Voltage: The EPS motor is a high-current component. If the battery voltage is low or the alternator output is weak, the motor will not receive enough electrical power to provide steering assist. 

Control Module (ECU) Fault: The EPS control unit detects an abnormal sensor signal (such as a malfunctioning torque sensor) and triggers fail-safe mode, partially or completely shutting down steering assist. 

Damaged Motor or Reduction Gear: Worn carbon brushes inside the motor or jammed reduction gears.

Mechanical Binding: Corrosion or seizing in the steering column or universal joint (U-joint). 

Diagnostic Tips: 

Check the Instrument Cluster: Is the EPS warning light (typically a steering wheel icon) illuminated? If so, connect an OBD diagnostic scanner to retrieve the fault codes.

Check the Battery: If the engine struggles to crank, voltage drops caused by an ageing battery may be disrupting EPS operation.

Hydraulic Power Steering (HPS) Models

Commonly found in older models, rugged 4x4s, or commercial vehicles.

Causes of Failure:

Low Power Steering Fluid: Insufficient fluid in the reservoir allows air to enter the hydraulic circuit. 

Drive Belt Slipping/Snapped: A loose, worn, or broken serpentine/drive belt prevents the steering pump from generating adequate hydraulic pressure. 

Worn Power Steering Pump: Internal wear in the pump leads to reduced pressure output.

Degraded Fluid/Incorrect Viscosity: Contaminated or aged fluid clogs the control valve body or internal strainer.

Internal Leak in Steering Rack: Blown internal rack seals prevent hydraulic pressure from effectively pushing the piston.

Diagnostic Tips: 

Inspect the Fluid: Open the power steering reservoir cap and verify if the fluid level sits below the MIN mark.

Listen for Noise: A whining or buzzing sound when turning the wheel usually points to pump cavitation (drawing air) or internal pump wear. 

Inspect the Drive Belt: With the engine running, observe if the steering pump belt is vibrating, slipping, or squealing.

General Causes (Applicable to All Models)

Low Tyre Pressure: The most frequently overlooked cause. Under-inflated front tyres significantly increase rolling and turning resistance; always check all four tyre pressures first. 

Misaligned Wheel Alignment: Severe deviations in geometry, particularly caster angle, create excessive self-aligning torque or mechanical binding, making the steering feel noticeably heavy. 

Seized Suspension/Steering Joints: Severely worn or seized tie rod ends, lower arm ball joints, or shock absorber top mount bearings create substantial mechanical friction. 

Recommended Action

Step 1 Self-Check: Start by verifying that all tyres are inflated to their recommended pressures. 

Stationary vs Moving Test: If the steering is extremely heavy at a standstill but lightens up once the car starts rolling, the issue is likely power assist deficiency (pump or EPS motor issue); if it remains heavy while driving, suspect mechanical binding (ball joints, internal steering rack) or alignment issues.

Safety Precaution: If heavy steering is accompanied by abnormal noises or an active warning light, avoid driving at high speeds. A failing steering system can seize or lose assist abruptly while on the move.