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Studebaker President Brake Light Switch Guide: 1943-1947 Models

Keeping the brake lights on your 1943-1947 Studebaker President working is a critical safety task; here are your options.

3 minutes to read 1943-1947 Studebaker President
Difficulty
2/5
Est. Time
0.75 hrs
DIY Doable?
✅ Yes
Shop Labor
$50-$100
🚫 Do not drive — It is not safe to drive a vehicle if the brake lights are not functioning correctly.
Key Takeaways
  • No major aftermarket brands offer a direct-fit switch; you will need to buy from a Studebaker specialist supplier.
  • The correct reproduction hydraulic switch is part number 666858, but it is not compatible with silicon brake fluid.
  • Many owners upgrade to a more reliable universal mechanical switch, which requires custom installation.
  • A failed switch is a critical safety hazard and should be replaced immediately.
The brake light switch on your Studebaker President is a pressure-activated switch. It is installed in the hydraulic brake line system. When you press the brake pedal, the pressure of the brake fluid increases. This pressure activates the switch, completing an electrical circuit and turning on your rear brake lights. Unlike modern cars that use a mechanical switch at the pedal, this hydraulic design was common for the era.

Symptoms of a Failing Brake Light Switch

A faulty brake light switch is a serious safety issue. If you notice any of these signs, you should inspect the switch immediately.

  • Brake Lights Do Not Turn On: This is the most dangerous symptom. If the switch fails to complete the circuit, drivers behind you will not know you are slowing down or stopping.
  • Brake Lights Stay On: The switch can fail in the 'on' position, leaving the brake lights constantly illuminated. This can confuse other drivers and will drain your battery when the car is off.
  • Leaking Brake Fluid: Since the switch is part of the hydraulic system, a failure in its housing can cause a brake fluid leak. This is a critical failure that can lead to a loss of braking power.

Choosing the Right Replacement Part

For a vehicle from the 1940s, traditional "aftermarket" brands do not produce a direct-fit brake light switch. Your options are different from those for a modern car and consist mainly of reproduction parts from specialty suppliers.

Reproduction Hydraulic Switch

The most direct replacement is a reproduction of the original hydraulic switch. Studebaker parts specialists offer a switch (part number 666858) that fits all 1942-1966 cars. This part functions just like the original. It is a pressure-activated switch that threads into the brake line.

Important Note on Brake Fluid: The commonly available reproduction switch (part number 666858) is specified as *not for use with silicon brake fluid*. Using silicon fluid with this switch can cause it to fail. If you have converted your system to silicon fluid, you must find a compatible switch or convert to a mechanical switch.

Mechanical Switch Conversion (Pro-Tip)

Many classic Studebaker owners choose to upgrade from the original hydraulic switch to a more reliable modern mechanical switch. These switches are activated by the physical movement of the brake pedal, not by fluid pressure.

Why Convert?
  • Reliability: Mechanical switches are not prone to leaking and are generally more durable than the hydraulic switches of the era.
  • Faster Response: They activate the moment the pedal moves, rather than waiting for hydraulic pressure to build.
  • System Isolation: A mechanical switch removes the switch from the hydraulic brake circuit, eliminating a potential point of fluid leakage.

This conversion requires some custom work, such as fabricating a small bracket to mount the switch near the pedal so its plunger is activated when the pedal is depressed. Universal mechanical switch kits are widely available from suppliers like Speedway Motors.

Estimated Replacement Costs

The cost for parts is low, but labor can vary if you choose to convert to a mechanical switch.

Part Type Estimated Cost
New Reproduction (Hydraulic) $15 - $35
New Aftermarket (Universal Mechanical) $10 - $25
Shop Labor (Direct Replacement) $50 - $100
Shop Labor (Mechanical Conversion) $100 - $250+

Frequently Asked Questions (FAQ)

Are there any recalls for the 1943-1947 Studebaker President brake light switch?

No, there are no active recalls or Technical Service Bulletins (TSBs) from the NHTSA for the brake light switch on this vehicle. Recalls for brake light switches on modern cars often relate to poor electrical contacts or switch malfunctions causing lights to stay on or off.

Is this a difficult part to replace myself?

Replacing the original hydraulic switch is relatively easy if you are comfortable working with brake lines and bleeding the brake system. It involves unscrewing the old switch, screwing in the new one, and then bleeding the brakes to remove any air that entered the system. Converting to a mechanical switch is more complex and may require drilling and fabricating a mounting bracket.

What is a New Old Stock (NOS) part?

New Old Stock refers to original parts made by the manufacturer that were never sold and have been stored for many years. For a 1940s vehicle, finding a true NOS brake light switch is rare. Most available parts are modern reproductions made by specialty suppliers.

Where is the brake light switch located?

The original hydraulic brake light switch is not located by the brake pedal. It is an inline switch installed somewhere along the vehicle's brake lines, often on the master cylinder or a junction block on the frame. A retrofitted mechanical switch would be located inside the car, mounted by the brake pedal arm.

Technical Specifications

OEM Part Numbers: 666858

Switch Type: Hydraulic Pressure Activated Terminal Type: Push-in / Bullet

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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.

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