Go-Parts
Cart 0
Your cart is empty
Add an item to see it appear here.
Wrenchy
Go-Parts Garage
Expert guides for diagnosing, troubleshooting, and replacing auto parts Expert guides for diagnosing and replacing auto parts
Browse All →
🛍️ Shop This Part

1955-1956 Studebaker E5 Truck Brake Light Switch Replacement Guide

Learn about the unique hydraulic brake light switch in your classic Studebaker E5 truck and how to replace it.

4 minutes to read 1955-1956 Studebaker E5
Difficulty
2/5
Est. Time
1 hrs
DIY Doable?
✅ Yes
Shop Labor
$100-$150
Used OEM Price
$10 - $25
🚫 Do not drive — Driving without functional brake lights is illegal and extremely dangerous to you and other drivers on the road.
Key Takeaways
  • The 1955-1956 Studebaker E5 uses a hydraulic pressure switch for the brake lights, not a mechanical one at the pedal.
  • A faulty switch is a critical safety issue; do not drive if your brake lights are not working correctly.
  • A new aftermarket switch from a brand like Standard Ignition is the most practical and reliable replacement choice.
  • Replacement is a feasible DIY task, but you MUST bleed the brakes afterward to ensure safety.
The brake light switch on your 1955-1956 Studebaker E5 is a vital safety part. Unlike modern vehicles that use a mechanical switch on the brake pedal, your truck uses a hydraulic pressure switch. This switch is screwed directly into the master cylinder or a brake line junction block. When you press the brake pedal, the building pressure of the brake fluid activates the switch. This closes an electrical circuit, sending power to the rear brake lights to let other drivers know you are slowing down.

Symptoms of a Failing Brake Light Switch

On a classic truck like the Studebaker E5, the signs of a bad brake light switch are usually very clear. Before you assume the switch is bad, always check your brake light bulbs and the fuse first, as these are common and simple fixes.

  • Brake Lights Do Not Turn On: This is the most common and dangerous symptom. If you've confirmed the bulbs and fuse are good, the switch is the most likely problem. The switch has failed internally and no longer completes the electrical circuit.
  • Brake Lights Stay On: If the switch fails in the 'on' position, it will constantly send power to the brake lights. This can confuse other drivers and will drain your battery when the truck is parked.
  • Lights Only Work Under Hard Braking: A worn-out switch may require more hydraulic pressure to activate. If your lights only come on during a hard stop, the switch is failing and needs immediate replacement.

A Note on Brake Fluid

Some owners of classic vehicles have reported that modern DOT 5 silicone brake fluid can cause reproduction hydraulic switches to fail prematurely. The Standard Ignition switch is designed as a direct replacement compatible with standard DOT 3 brake fluid, which was original to the vehicle. Always verify fluid compatibility before installation.

Choosing the Right Aftermarket Switch

For a vehicle from the mid-1950s, finding a New Old Stock (NOS) Studebaker part is nearly impossible and would be very expensive. The most practical and reliable choice is a new aftermarket switch.

  • New Aftermarket (Recommended): Brands like Standard Ignition (Standard Motor Products) are well-known for producing reliable replacement parts for classic vehicles. These switches are made to fit and function like the original and are readily available.
  • New Old Stock (NOS): These are original, unsold parts. While authentic, they are extremely rare, costly, and may have degraded over 70+ years in storage.
  • Used OEM: A used part from a salvage yard is a cheap but risky option. There is no guarantee of its condition or remaining lifespan.

Consider a Mechanical Switch Conversion

For added reliability, some Studebaker owners modify their vehicles to use a modern mechanical brake light switch mounted by the brake pedal. This eliminates the hydraulic switch and its potential for leaks or fluid-related failures. However, this is a custom job that requires fabrication and wiring skills. For most owners, a new hydraulic switch is the simplest solution.

Typical Replacement Costs

Replacing the brake light switch is an affordable repair. The main cost variation comes from shop labor rates.

Part Type Part Cost Labor Cost Total Cost
New Aftermarket $15.52 $100 - $150 $115 - $165
DIY Replacement $15.52 $0 $15.52
Cost estimates are for the part and 1 hour of shop labor at $100-$150/hr. Brake fluid cost is extra.

Frequently Asked Questions (FAQ)

Where is the brake light switch located on my 1955-1956 Studebaker E5?

The brake light switch is not inside the cab. It is a hydraulic pressure switch located under the truck, screwed into the master cylinder or a nearby brake line junction block on the frame. It will have two wires connected to it.

Is it hard to replace the brake light switch myself?

For a DIYer, this is a fairly easy job, but it requires more than just unscrewing the part. Because it's part of the hydraulic brake system, you must bleed the brakes after replacing the switch to remove any air that enters the lines. This step is critical for safety. The job itself involves unplugging wires and swapping the switch, which can be done in under an hour.

How do I test my brake light switch?

After checking the bulbs and fuse, you can test the switch itself. Locate the switch and unplug the two wires. Use a small jumper wire to connect the two wire terminals together. If the brake lights turn on, the switch is bad and needs to be replaced. If they do not light up, the problem is elsewhere in the wiring.

Do I need to bleed the brakes after replacing the switch?

Yes. Any time you open the hydraulic brake system, air can get in. You must bleed the brakes after replacing the switch to ensure there is no air in the lines, which could cause a soft pedal or complete brake failure.

Technical Specifications

Hydraulic Pressure Activated, Screw-In, 2-Terminal

Wrenchy
Article researched & written by
Go-Parts' AI research assistant. Every article is backed by live web research, verified OEM data, and real technician knowledge — so you get accurate, up-to-date information you can trust.
Meet Wrenchy → Updated Jul 21, 2026

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.

Year Coverage
This article covers the Brake Light Switch for:
In this article
🛍️ Shop This Part
Jump to ▴

Email This Guide

We'll send you a link to this article so you can read it later or share it.

Added to cart · Part