Your Guide to the 1963-1964 Studebaker 8E12D Hydraulic Brake Light Switch
Understanding the pressure-activated switch in your classic Studebaker truck is key to a safe and reliable repair.
- The 1963-64 Studebaker 8E12D uses a hydraulic pressure switch, not a mechanical one.
- The available aftermarket replacement is from Standard Ignition, but it is not recommended for use with silicone brake fluid.
- Common failure symptoms are brake lights that don't work, stay on, or a fluid leak at the switch.
- Before replacing the switch, always check the bulbs and fuse first.
Is Your Studebaker's Brake Light Switch Failing?
On a classic truck like the Studebaker 8E12D, diagnosing a faulty brake light switch is usually straightforward. The simple electrical system means there are few parts to check. Before you replace the switch, always check the brake light bulbs and the fuse first. These are common points of failure and are easier to fix.
Pro Tip: Check Bulbs and Fuses First
Before spending money on a new switch, take a moment to inspect the brake light bulbs and the related fuse. A burned-out bulb or a blown fuse can mimic the symptoms of a failed switch and are much simpler to fix.
Symptoms of a Bad Brake Light Switch
A failing brake light switch poses a significant safety risk. The symptoms are clear and should be addressed immediately.
- Brake Lights Do Not Turn On: This is the most dangerous symptom. If the bulbs and fuse are good, the switch has likely failed internally and can no longer complete the electrical circuit.
- Brake Lights Stay On: The switch can fail in the 'on' position, causing the brake lights to remain lit even when you are not braking. This will drain your battery and confuse other drivers.
- Leaking Brake Fluid: Since this is a hydraulic switch, a failure in the switch's body or seal can cause brake fluid to leak from the switch itself. This is a serious safety issue that can lead to a loss of braking power.
Choosing the Right Aftermarket Switch
For a vehicle of this age, finding a new original Studebaker part is not practical. The market consists of New Old Stock (NOS) parts, which are rare and expensive, or new aftermarket parts.
New Aftermarket: This is the most common and practical choice. Brands like Standard Ignition (Standard Motor Products) produce direct-fit replacement hydraulic switches. These parts are made to match the original specifications for fit and function and are a reliable option for most owners.
Important: Silicone Brake Fluid and Switch Failure
Many classic car owners have reported that modern silicone brake fluid can cause reproduction hydraulic brake light switches to fail prematurely. The original-style switches were not designed for use with silicone fluid. If you are using silicone brake fluid, you may experience repeated switch failures. An alternative pursued by some owners is to modify the truck to use a more modern mechanical switch at the brake pedal, which eliminates this issue entirely.
Cost Comparison for Your Studebaker 8E12D
| Part Type | Price Range | Notes |
|---|---|---|
| New OEM (NOS) | Varies widely | New Old Stock. Hard to find, may be brittle from age. |
| New Aftermarket | $15.52 | The most practical and available option. Standard Ignition is a common brand. |
| Used OEM | $5 - $20 | Not recommended. It's a wear item and a used part has an unknown lifespan. |
| Shop Labor | $50 - $100 | Replacement is simple and takes less than an hour. |
Frequently Asked Questions
Is the brake light switch on a Studebaker 8E12D mechanical or hydraulic?
It is a hydraulic pressure switch located on the master cylinder, not a mechanical switch at the brake pedal.
Why do my new aftermarket brake light switches keep failing?
If you are using silicone brake fluid, it may be causing the seals in the reproduction switches to fail. This is a well-documented issue in the classic car community. Consider switching back to a compatible DOT 3 or DOT 4 fluid or converting to a mechanical pedal switch.
Are there any recalls for the 1963-1964 Studebaker 8E12D brake light switch?
No recalls or Technical Service Bulletins (TSBs) were found in the NHTSA database for this specific part. This is normal for a vehicle of this vintage.
Is replacing the brake light switch a difficult job?
No, it is a simple job for a DIY mechanic. It involves unplugging the two wires, unscrewing the old switch, and screwing in the new one. You will need to have a rag handy to catch any dripping brake fluid and you may need to bleed the brakes afterward if air enters the system.
Technical Specifications
OEM Part Numbers: 666858
Hydraulic pressure activated switch with two screw-on or bullet-type electrical terminals. Thread size is typically 1/8-NPT.
We Have This Part in Stock
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.