How to Install Electric Power Steering on an Old Car

Upgrading an old car with modern conveniences can significantly enhance the driving experience, and installing electric power steering (EPS) is a prime example. While many classic vehicles offer a unique charm, their heavy, unassisted steering can be cumbersome, especially in urban environments or during parking. This guide will walk you through the comprehensive process of how to install electric power steering on an old car, covering everything from understanding the system to the detailed steps of integration, ensuring you can enjoy a smoother, more responsive ride.

Understanding Electric Power Steering (EPS)

how to install electric power steering on an old car — How to Install Electric Power Steering on an Old Car

Electric Power Steering (EPS) systems replace traditional hydraulic power steering with an electric motor that assists the driver in turning the wheels. Unlike hydraulic systems, which rely on a pump, hoses, and fluid, EPS uses an electric motor attached to the steering column or rack. A control unit (ECU) monitors steering wheel input and vehicle speed, then directs the motor to provide the appropriate level of assistance. This results in numerous benefits, including improved fuel efficiency, reduced maintenance, and a more direct steering feel.

Why Upgrade an Old Car to EPS?

The decision to install electric power steering on an old car often stems from a desire to blend classic aesthetics with modern driveability. Here are the primary reasons why this upgrade is gaining popularity among vintage car enthusiasts:

Improved Driving Comfort: The most immediate benefit is significantly lighter steering, making low-speed maneuvers and parking effortless. This reduces driver fatigue, especially on longer journeys or in heavy traffic.
Enhanced Fuel Efficiency: Hydraulic power steering pumps continuously draw power from the engine, even when not actively steering. EPS systems only consume power when assistance is needed, leading to a small but measurable improvement in fuel economy.
Reduced Maintenance and Leaks: Eliminating hydraulic fluid means no more fluid checks, no more leaky hoses, and no more noisy pumps. This simplifies maintenance and cleans up the engine bay.
Customizable Steering Feel: Many aftermarket EPS systems offer adjustable assistance levels, allowing drivers to tailor the steering feel to their preference or specific driving conditions.
Easier Engine Bay Access: Removing the hydraulic pump and associated components frees up valuable space in the engine bay, which can be beneficial for other modifications or simply for better access for maintenance.
Safety and Control: Lighter steering can improve a driver’s ability to react quickly in emergency situations, offering better control, especially for those less accustomed to heavy, unassisted steering.

Key Considerations Before Installation

Before you embark on the journey to install electric power steering on an old car, thorough planning and consideration are crucial. This isn’t a one-size-fits-all modification, and careful assessment of your vehicle and your capabilities will save time and prevent potential issues.

Vehicle Compatibility and Space

First, assess the physical space available in your vehicle’s interior, specifically around the steering column. Most aftermarket EPS units are designed to integrate into the steering column itself, often requiring cutting and shortening the existing shaft. You’ll need enough room for the EPS motor and control unit without interfering with pedals, dashboard components, or knee room. Some cars, particularly those with very tight dashboards or unique column designs, might present significant challenges. Measure carefully and compare against the dimensions of the EPS kit you’re considering.

Electrical System Requirements

EPS systems are electrical and require a stable power supply. Old cars often have simpler electrical systems not designed to handle the peak power draw of an EPS unit (which can be 40-60 amps under heavy load). You’ll need to verify that your alternator can provide sufficient amperage and that your wiring harness can handle the load. This might necessitate an alternator upgrade, the installation of a dedicated fused power circuit, and possibly a new battery. Neglecting this could lead to dimming lights, erratic engine behavior, or even system failure.

Skill Level and Tools Required

Installing EPS is a moderately to highly complex task. It typically involves:

Mechanical Work: Disassembly of the steering column, cutting and shortening steel shafts, precise fitting of adapters, and potentially some welding or fabrication.
Electrical Work: Wiring the EPS unit to the vehicle’s power, ignition, and potentially a vehicle speed sensor (VSS). This requires a good understanding of automotive electrical systems, proper crimping, soldering, and fusing techniques.
Safety-Critical Component: The steering system is paramount to vehicle safety. Any mistakes here can have dire consequences. If you are not confident in your mechanical or electrical skills, professional installation is strongly recommended.

Cost vs. Benefit Analysis

Aftermarket EPS kits can range from a few hundred to over a thousand dollars, not including potential costs for electrical upgrades, specialized tools, or professional labor. Weigh this investment against the benefits. For a daily driver or a car frequently used for long trips, the comfort and convenience might justify the cost. For a show car that rarely moves, the aesthetic and maintenance benefits might be enough. For reliable parts and accessories, check out **maxmotorsmissouri.com**.

Legal and Safety Regulations

Before making such a significant modification, research any local vehicle inspection or registration regulations regarding steering modifications. Ensure that your modification will be road-legal and safe. Always prioritize safety over convenience.

Choosing the Right EPS Kit

Selecting the appropriate Electric Power Steering kit is a critical step. The market offers a variety of options, from universal kits to those designed for specific vehicle types.

Universal EPS Kits

These are the most common for old cars, as specific kits for vintage models are rare. Universal kits typically consist of:

EPS Motor and Gearbox: This is the core unit that provides assistance. It usually integrates into the steering column.
Electronic Control Unit (ECU): Manages the motor’s operation based on sensor inputs (torque, speed).
Wiring Harness: Connects the motor, ECU, and vehicle’s electrical system.
Steering Shaft Adapters/Splines: Crucial components that allow the EPS unit to connect to your existing steering column’s upper and lower shafts.

When choosing a universal kit, look for one that:
* Is reputable: Read reviews and choose brands known for quality and reliability.
* Offers adjustability: Many systems allow you to adjust the level of assistance.
* Provides clear instructions: While general guides like this one help, specific instructions for your chosen kit are essential.
* Has good customer support: In case you encounter installation issues.

Car-Specific or Semi-Specific Kits

For popular classic cars (e.g., certain Mustangs, Camaros, or classic trucks), you might find kits marketed as “car-specific.” These often come with pre-fabricated brackets or shafts that reduce the amount of custom fabrication required. While more expensive, they can significantly simplify the installation process.

Key Components to Look For

Regardless of the kit type, ensure it includes all necessary parts for a complete installation:
* Torque Sensor: This sensor detects how much effort the driver is applying to the steering wheel, informing the ECU how much assistance to provide.
* Vehicle Speed Sensor (VSS) Input: While some basic systems are speed-independent, a VSS input allows the ECU to vary assistance (less at high speed, more at low speed), providing a more natural feel. If your old car lacks a VSS, you might need an aftermarket solution (e.g., a GPS-based VSS signal generator).
* Ignition and Battery Power Connections: Ensure the wiring is robust and includes proper fusing.

Tools and Materials Needed

A successful EPS installation requires a well-equipped garage and attention to detail. Gather all your tools and materials before starting to avoid interruptions.

Essential Tools:

Basic Hand Tools: Socket sets, wrenches (metric and imperial, depending on your car), screwdrivers, pliers.
Torque Wrench: Crucial for tightening steering components to factory specifications.
Measuring Tools: Tape measure, ruler, calipers for precise shaft measurements.
Cutting Tools: Angle grinder with cutting and grinding discs, hacksaw, or a dedicated steering shaft cutting tool.
Welding Equipment (if required): MIG or TIG welder, auto-darkening helmet, gloves. Only if you or a professional need to modify the steering shaft by welding.
Electrical Tools: Multimeter, wire strippers, crimping tools, soldering iron, heat gun (for heat shrink tubing).
Safety Gear: Safety glasses, gloves, ear protection, jack stands, wheel chocks.
Marker/Scribe: For marking cut lines accurately.
File/Deburring Tool: To smooth cut edges on the steering shaft.

Materials:

The EPS Kit: Your chosen electric power steering unit with all components.
High-Quality Wiring: Appropriate gauge wire for power and ground connections (often supplied with the kit, but verify).
Fuses and Fuse Holders: Heavy-duty fuses (e.g., 40-60 amp MIDI or Maxi fuse) for the main power line.
Heat Shrink Tubing/Electrical Tape: For insulating electrical connections.
Cable Ties/Wire Loom: For tidying and protecting wiring.
Loctite (Threadlocker): For securing bolts on steering components (medium strength, blue).
Grease: For lubricating moving parts, if recommended by the EPS kit manufacturer.
Rust Inhibitor/Primer: For exposed metal areas after cutting/grinding.

Step-by-Step EPS Installation Guide

This guide provides a general overview of the process. Always refer to your specific EPS kit’s instructions for detailed steps and torque specifications.

Step 1: Preparation and Safety

Disconnect the Battery: This is a crucial safety step before working on any electrical system.
Secure the Vehicle: Lift the front of the car and place it securely on jack stands. Chock the rear wheels.
Remove Steering Wheel: Disconnect the horn, then remove the steering wheel nut and pull the wheel off. Be careful with any airbag systems if your car has one (though unlikely on “old cars”).
Mark Steering Alignment: Before disassembling anything, mark the alignment of the steering shaft components to ensure everything goes back together straight. Use a paint pen or scribe to mark the steering column, intermediate shaft, and steering box/rack.
Remove Dashboard Components: You may need to remove parts of the dashboard, instrument cluster, or lower trim panels to access the steering column bolts and provide working space.

Step 2: Removing the Old Power Steering System (if applicable)

If your car currently has hydraulic power steering, you’ll need to remove it. If it’s manual steering, skip this step.

Drain Hydraulic Fluid: Place a drain pan under the power steering pump. Disconnect the return line and let the fluid drain.
Remove Hoses and Lines: Disconnect all high-pressure and return lines from the pump and steering box/rack.
Remove Power Steering Pump: Unbolt the pump from the engine and remove its mounting bracket.
Remove Reservoir: Take out the power steering fluid reservoir.
Clean Up: Clean any spilled fluid and cap off any open ports on the steering box/rack if you’re retaining it (though often, an EPS conversion implies a full steering column modification, not just pump removal).

Step 3: Modifying the Steering Column

This is often the most complex and critical part of the installation.

Remove Existing Steering Column: Unbolt the steering column from its mounting points under the dash and at the firewall. Disconnect any electrical connectors. Carefully remove the entire column assembly from the vehicle.
Disassemble the Column: Take apart the steering column, separating the outer casing from the inner steering shaft. You will likely need to remove switches, wiring, and bearings.
Measure and Cut the Steering Shaft: This is where precision is vital.
- Measure the length of the EPS motor unit.
- Determine where the EPS unit will integrate into your column (usually between the upper and lower shaft sections).
- Carefully measure and mark the existing steering shaft for cutting. The goal is to shorten the shaft sufficiently to accommodate the EPS unit’s length while maintaining overall steering geometry and proper component fitment.
- Use an angle grinder or hacksaw to make precise, straight cuts. Deburr the edges thoroughly.
Install EPS Motor Unit:
- Fit the EPS motor and gearbox onto the shortened upper steering shaft using the provided adapters and splines.
- Secure the EPS unit to the steering column’s outer casing using custom brackets or the kit’s mounting hardware. This may involve drilling new holes or light fabrication. Ensure the unit is rigidly mounted and does not flex.
- Connect the lower steering shaft to the output spline of the EPS unit.
- Ensure all universal joints are properly indexed and tightened. Use Loctite on all critical fasteners.

Step 4: Wiring the EPS System

Correct electrical hook-up is vital for performance and safety.

Main Power Connection:
- Run a heavy-gauge wire (e.g., 8-gauge or 10-gauge, check kit instructions) directly from the battery (or a main power distribution point) to the EPS control unit.
- Install a high-amp fuse (as recommended by the kit) as close to the battery as possible.
Ground Connection:
- Connect the EPS control unit’s ground wire to a clean, unpainted chassis ground point.
Ignition Switched Power:
- Connect a smaller gauge wire from the EPS unit to a reliable 12V ignition-switched power source (e.g., accessory circuit) so the EPS only activates when the car is running.
Vehicle Speed Sensor (VSS) (Optional but Recommended):
- If your kit supports it and you have a VSS, connect it. This allows the EPS to provide less assistance at higher speeds for better road feel. If your car doesn’t have a VSS, you may need an aftermarket solution (e.g., GPS-based VSS signal generator) or run the system without speed input (assistance level will be constant).
Route and Secure Wiring: Route all wiring safely, away from hot exhaust components, sharp edges, and moving parts. Use wire loom and cable ties for a neat and protected installation.

Step 5: Reassembly and Testing

Reinstall Modified Steering Column: Carefully slide the modified steering column back into the car, guiding it through the firewall and aligning it with its mounting points. Bolt it securely in place.
Connect Steering Linkage: Connect the lower end of the steering column/intermediate shaft to the steering box or rack. Ensure the previous alignment marks line up.
Reconnect Electrical: Reconnect all electrical connectors that were previously detached (switches, horn, etc.).
Reinstall Steering Wheel: Reattach the steering wheel, ensuring it’s straight and centered. Tighten the steering wheel nut to spec.
Reconnect Battery: Reconnect the car’s battery.
Initial Power-Up and Calibration:
- Turn the ignition to the “ON” position (do not start the engine yet).
- Follow the EPS kit’s instructions for initial calibration or setup. This might involve turning the steering wheel lock-to-lock a few times.
- Check for any warning lights or error codes.
- Slowly turn the steering wheel side-to-side to feel the assistance.
Engine Start and Testing:
- Start the engine.
- Verify that the steering assistance is working correctly.
- Carefully drive the car a short distance at low speed in a safe area to check steering feel and response. Ensure there are no strange noises or excessive play.
Road Test: Once confident, take the car for a proper road test, gradually increasing speed and observing steering performance at various speeds. Ensure the steering returns to center properly and the assistance feels natural.

Common Challenges and Troubleshooting

Even with careful planning, you may encounter issues when you install electric power steering on an old car.

Electrical Gremlins: The most common problem. Check all connections, fuses, and ground points. Use a multimeter to verify voltage at the EPS unit. Ensure your alternator is producing enough power.
Mechanical Fitment Issues: The EPS unit might interfere with other components. This usually requires custom fabrication of brackets or careful repositioning.
Poor Steering Feel:
- Too light: If adjustable, reduce assistance. If not, consider a VSS input to reduce assistance at higher speeds.
- Too heavy: Check power supply, ensure the unit is receiving full voltage. Check for binding in steering components.
- Not returning to center: Check steering alignment, ball joints, and tie rod ends for excessive friction or binding.
Noise: Whining or grinding usually indicates a mechanical issue (e.g., rubbing components, loose mounting) or an electrical issue (e.g., insufficient power causing the motor to strain).
Intermittent Operation: Often an electrical issue – loose connections, intermittent short circuits, or a failing power source.

Legal and Safety Considerations

Installing electric power steering on an old car is a significant modification to a safety-critical system.

Professional Assistance: If you’re not fully confident in your abilities, especially with cutting and welding steering shafts or complex electrical wiring, hire a qualified professional. A mistake in the steering system can have catastrophic consequences.
Local Regulations: Check your local vehicle inspection and registration laws. Some regions have specific requirements for modified vehicles, and poorly executed modifications could lead to your car failing inspection or being deemed unroadworthy.
Regular Inspections: After installation, regularly inspect all steering components, including the EPS unit, mounting brackets, and electrical connections, to ensure everything remains secure and functional.

By carefully following these guidelines, you can successfully install electric power steering on an old car, transforming its driveability and enhancing your enjoyment of a classic vehicle. The improved comfort and modern feel will make every journey a pleasure.

Last Updated on October 10, 2025 by Cristian Steven

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