Pressure Switch Question

[Ramblin Reck]

I have a (faulty?)pressure switch from my 1939 Ford which I have replaced. Does anyone know if it can be bench tested and how that is done? Thanks!

[Kube]

Pressure switch?

[V8COOPMAN]

Originally Posted by Ramblin Reck

I have a (faulty?)pressure switch from my 1939 Ford which I have replaced. Does anyone know if it can be bench tested and how that is done? Thanks!

Assuming that you are talking about the BRAKE light PRESSURE SWITCH? Are we close? If so, and since the thread are going to be sort of hard to find a match for for testing, the easiest way to test is screwed into the fitting on the master cylinder. BEWARE that you must not have allowed a bunch of air in while changing, or bleed it out to create the hydraulic pressure needed to activate the switch.

With all of those parameters satisfied, and the two wires hooked-up to the switch, push the pedal down. IF the brake lights do not illuminate, disconnect the two wires from the switch. NOW, touch the ends of both wires together. IF the brake lights illuminate now, the switch is likely defective. DD
.

[deuce lover]

Air compressor.With the right fittings and adjusting the pressure.I have tested the oil pressure senders this way before.

[Ramblin Reck]

Originally Posted by Kube

Pressure switch?

Kube

Brake Light Pressure Switch

[Ramblin Reck]

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Originally Posted by V8COOPMAN

Assuming that you are talking about the BRAKE light PRESSURE SWITCH? Are we close? If so, and since the thread are going to be sort of hard to find a match for for testing, the easiest way to test is screwed into the fitting on the master cylinder. BEWARE that you must not have allowed a bunch of air in while changing, or bleed it out to create the hydraulic pressure needed to activate the switch.

With all of those parameters satisfied, and the two wires hooked-up to the switch, push the pedal down. IF the brake lights do not illuminate, disconnect the two wires from the switch. NOW, touch the ends of both wires together. IF the brake lights illuminate now, the switch is likely defective. DD
.

V8COOPMAN
You assume correctly that it is the Brake Light Pressure Switch. BLS is already off of the MC and on my bench and replaced by a good one. New one works fine on the car. This one did too until it quit. While this bad one was on the MC, I did the two wire touch and the lights worked so i replaced the switch. Just looking to verify that this switch really did go bad in four months time assuming there is an easy quick way to bench test. Unfortunately I trashed the old MC.

[Kube]

Originally Posted by Ramblin Reck

V8COOPMAN
You assume correctly that it is the Brake Light Pressure Switch. BLS is already off of the MC and on my bench and replaced by a good one. New one works fine on the car. This one did too until it quit. While this bad one was on the MC, I did the two wire touch and the lights worked so i replaced the switch. Just looking to verify that this switch really did go bad in four months time assuming there is an easy quick way to bench test. Unfortunately I trashed the old MC.

From what you are describing, yes, the "new" switch is poopy. Not a big surprise. I'd suggest you seek a NOS switch. They last for years upon years.

[19Fordy]

For those considering an upgrade in their brake light pressure switch, this
was just posted on HAMB. Looks promising but, expensive. Thread is worth reading.
https://www.jalopyjournal.com/forum/...grade.1254002/

[Ken/Alabama]

If you’re not looking for 100% restoration, what I’ve done is install a relay within the circuit. Then the brake light switch just makes an breaks the ground to the switch. A 6 volt horn relay works great.

[V8COOPMAN]

.

These work great, too! They even come 'LEFT' or 'RIGHT Handed'. DD

[deuce lover]

Coopman has it right! Those are less than $10 and work every time.

[aussie merc]

pedal switch way to go did 3 pressure switch's inside 12 months [macs & bd ] supplied went to pedal switch 6 years and counting

[Ramblin Reck]

peddle switch it is when this pressure switch goes kaput
now to figure out where to mount it on a 1939 vert. In the cab



also like ken's idea of a relay within the circuit but have no idea how to wire this up

[Ramblin Reck]

Originally Posted by Ken/Alabama

If you’re not looking for 100% restoration, what I’ve done is install a relay within the circuit. Then the brake light switch just makes an breaks the ground to the switch. A 6 volt horn relay works great.

Ken
Sounds interesting. Not sure how this is wired up?

[tubman]

I have had old Fords with hydraulic brakes for over 60 years, and have never had a problem with an original switch. It may be because that's all I've ever used. If I ran across a decent looking one, I'd clean it up and throw it in a drawer.

[V8COOPMAN]

Originally Posted by Ramblin Reck

peddle switch it is when this pressure switch goes kaput
now to figure out where to mount it on a 1939 vert. In the cab

Here ya go! Picture this mounted on the BOTTOM side of the driver side wooden floor board. That is the brake pedal you see running vertically in picture, which allows switch arm to be activated. DD

[Ramblin Reck]

Originally Posted by V8COOPMAN

Here ya go! Picture this mounted on the BOTTOM side of the driver side wooden floor board. That is the brake pedal you see running vertically in picture, which allows switch arm to be activated. DD

Roger That and Thanks That really helps

[36coupe]

I found one Friday at my local NAPA. Not sure if the prongs are the right diameter, a little larger than 1/8”.