brake lights stuck on

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Mar 10, 2012 | 03:55 PM

carbs & chrome

Thread Starter

Senior User

Joined: May 2009

Posts: 470

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From: Utah, USA

brake lights stuck on

I got home today from a quick drive to the hardware store in the '54, and noticed my brake lights were stuck on. Must have been on for awhile, because my lenses are damaged from heat. I am assuming I have a bad brake switch, but just incase is there anything else I should look into? Thanks.

Mar 10, 2012 | 04:35 PM

raytasch

Believe Nothing

Joined: Jun 2004

Posts: 7,514

Likes: 398

From: W. Central FL.

The original type pressure switches are known for failure from corrosion, internal and external. Brake fluid, being hygroscopic, draws moisture that causes corrosion, internal and external. That is one reason why brake fluid should be changed periodically. Of course, make certain the pedal is returning all the way. I went to silicon fluid back when I was playing with this old stuff on a regular basis. I've read that the newer fluids are better.
These pressure switches fail another way in that they take more pressure to activate the light. This is dangerous in that you roll up to a stop while braking easy and the brake lights never come on. Many rear end accidents because of this.

Mar 10, 2012 | 04:39 PM

r_reed

Laughing Gas

Joined: Jul 2003

Posts: 1,224

Likes: 19

From: scotia. NY 12302

a bad pressure relief valve in the master can keep the pressure up when you let off the pedal. if you notice any "drag" on the truck when you drive it, that would inidcate pressure when you are not on the break. i had that problem once.

Mar 10, 2012 | 09:16 PM

49fordpickumup

Elder User

Joined: May 2006

Posts: 907

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From: Kansas City, Mo

Talk a look at the switch. It maybe out of adjustment. It's most likely the switch is on all the time or the brake pedal arm is to close to the switch. chuck

Mar 10, 2012 | 11:42 PM

NumberDummy

Ford Parts Specialist

Joined: Nov 2006

Posts: 88,826

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From: Simi Valley, CA

Quote:

Originally Posted by 49fordpickumup

Take a look at the switch. It maybe out of adjustment.

It's most likely the switch is on all the time or the brake pedal arm is too close

to the switch.

The brake aka stop light switch is non adjustable. It's pressure activated by stepping on the brake pedal, threads directly into the front of the master cylinder or to a brass fitting that does the same thing.

The master cylinder is firewall mounted.

Studebaker cars/trucks used the same switch (#666858 same as C1AZ-13480-A). The master cylinder mounts on the frame rail next to the brake pedal, but this ain't no Studebaker.

This switch is notorious for getting gummed up with dirty brake fluid.

C1AZ-13480-A (replaced 91A-13480, 0A-13480, 11A-13480) .. Brake (Stop) Lamp Switch (Motorcraft SW-24) / Available from Ford and a gazillion parts stores.

Applications: 1939/66 FoMoCo vehicles.

Mar 11, 2012 | 05:14 PM

abe

Fleet Owner

Joined: Dec 2000

Posts: 25,378

Likes: 5,387

From: Central PA

If you need a new switch, think about getting one from Mid-Fifty. They have one that activates the brake lights with less pedal pressure than stock, allowing your brake lights to come on sooner.