Brake light switch brake conversion
5th Wheeling
Joined: Oct 2024
Posts: 42
Likes: 20
FYI:
The plastic switch port for imbalance is also used for bleeding the brake. When a line breaks, lets say in the rear the spool inside will shift to allow the front to continue. This make bleeding not really possible as it would trip when the line is opened. The plastic switch gets replaced with one that does not allow the spool to lock up. These are available online and are a few bucks. Again I would use the speed bleeders if you don't have a helper to "Pump and hold"
Thanks,
Tony
The plastic switch port for imbalance is also used for bleeding the brake. When a line breaks, lets say in the rear the spool inside will shift to allow the front to continue. This make bleeding not really possible as it would trip when the line is opened. The plastic switch gets replaced with one that does not allow the spool to lock up. These are available online and are a few bucks. Again I would use the speed bleeders if you don't have a helper to "Pump and hold"
Thanks,
Tony
AirForceVet
Joined: Mar 2004
Posts: 602
Likes: 126
From: Spotsylvania,Virginia
Brake lights staying on
Stock style pressure switches are fine and never let me down. They are dead simple, can be plumbed in just about anywhere convenient. I believe that those who report issues/disappointment have issues outside of the switch itself (such as bad wiring), or incorrect installation (not using proper deep socket with minimal torque).
Tuned
Joined: Aug 2024
Posts: 323
Likes: 158
From: Texarkana
I'm having a problem with my brake lights staying on intermittently, my truck is a 1955 F250 with stock braking system. I had this problem before and changed the master cylinder, it fixed the problem for a while up until yesterday. I had replaced the switch before changing the master cylinder thinking it was the problem, then I replaced the master cylinder. I thought I had the plunger rod to tight so I adjusted it out away from the master cylinder plunger. It worked for a while, until I used my brakes, and the third brake light I have install in the rear window started flickering (I can see the reflection in the rear glass when it flickers). The brake pedal return spring is tight, I can tap the brake pedal a couple of times and all is good for a very short time. Could it be the pressure switch is to sensitive, the plunger return spring inside the master cylinder is weak?
Have you ever changed the break fluid?
AirForceVet
Joined: Mar 2004
Posts: 602
Likes: 126
From: Spotsylvania,Virginia
Have you checked your grounds? It sounds more electrical than the mechanical pressure switch. It will amaze you how much a bad ground can play havoc with a electrical system. I would even go as far as replacing the ground wire and cleaning the surfaces to make sure that the contacts are to metal to metal. Rust and pain under the contact will also cause problems.
Have you ever changed the break fluid?
Have you ever changed the break fluid?
Tuned
Joined: Aug 2024
Posts: 323
Likes: 158
From: Texarkana
The aftermarket break switches listed here take about 30 minutes to put in and are very simple. But if the problem is not the switch you would be wasting your time.
Best of luck.
Parts Nerd Extraordinaire
Joined: Sep 2010
Posts: 4,347
Likes: 1,773
From: Western NY
Can you share your brake system components? Are you exactly 100% stock?
Which specific brake pressure switch are you using?
Which specific master cylinder?
What wheel cylinders?
Any proportioning valves, electric parking brake solenoids, etc?
Have you check the residual brake pressure with a brake pressure tool such as this?
https://www.summitracing.com/parts/sum-800114
Which specific brake pressure switch are you using?
Which specific master cylinder?
What wheel cylinders?
Any proportioning valves, electric parking brake solenoids, etc?
Have you check the residual brake pressure with a brake pressure tool such as this?
https://www.summitracing.com/parts/sum-800114
AirForceVet
Joined: Mar 2004
Posts: 602
Likes: 126
From: Spotsylvania,Virginia
Have you ran a jumper wire to the terminals and see if that is the issue? I would take a test light to the terminals on the brake switch to see it is a bad switch / bad feed for the hot wire. If that is not the issue I would by pass the switch with a jumper wire and run down the wires all the way to the lights.
The aftermarket break switches listed here take about 30 minutes to put in and are very simple. But if the problem is not the switch you would be wasting your time.
Best of luck.
The aftermarket break switches listed here take about 30 minutes to put in and are very simple. But if the problem is not the switch you would be wasting your time.
Best of luck.
AirForceVet
Joined: Mar 2004
Posts: 602
Likes: 126
From: Spotsylvania,Virginia
The only thing different about the braking system from original 1955 F250 is I went to the wider brake drum and shoe that was on the 1956 model year. The pressure switch is stock replacement , stock master cylinder replacement, wheel cylinders stock replacement, no proportioning valve or parking brake solenoid.
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Parts Nerd Extraordinaire
Joined: Sep 2010
Posts: 4,347
Likes: 1,773
From: Western NY
I was hoping for manufacturer and part numbers, especially on the pressure switch so we could as certain it's properties and specifications.Have you check the residual brake pressure with a brake pressure tool such as this? This will help determine if the switch is faulty or if you have any issues outside the switch. https://www.summitracing.com/parts/sum-800114
Fleet Mechanic
Joined: Sep 2010
Posts: 1,832
Likes: 467
From: Mason City, Iowa
I agree with pltnsgt06 about using the test light. I would isolate the switch first by disconnecting the load side connection to the brake lights and wire a test bulb to that terminal. Get a good socket for the bulb, splice on some long wires to it so you could run it into the cab, then connect one side of the bulb to a good ground, then other side to your brake light switch. Take it for a quick ride, (use hand signals if anyone is behind you) and see if your are still getting the intermittent problem by seeing if the bulb goes on and offwith the breaks not being used.
AirForceVet
Joined: Mar 2004
Posts: 602
Likes: 126
From: Spotsylvania,Virginia
I was hoping for manufacturer and part numbers, especially on the pressure switch so we could as certain it's properties and specifications.Have you check the residual brake pressure with a brake pressure tool such as this? This will help determine if the switch is faulty or if you have any issues outside the switch. https://www.summitracing.com/parts/sum-800114
Parts Nerd Extraordinaire
Joined: Sep 2010
Posts: 4,347
Likes: 1,773
From: Western NY
DC doesn't mention the switching PSI. Some models are as low as 45 psi, which would be on the sensitive side of things. Even higher pressure switches of 120psi are pretty low.
Again, being sure of the electrics as described above by others and checking for residual pressure with the gauge as suggested will help eliminate guesses and assumptions.
I would caution against using a physical mechanical switch without getting to the bottom of the real issue. If there is residual pressure in your system, you want to correct that and not simply mask it.
Again, being sure of the electrics as described above by others and checking for residual pressure with the gauge as suggested will help eliminate guesses and assumptions.
I would caution against using a physical mechanical switch without getting to the bottom of the real issue. If there is residual pressure in your system, you want to correct that and not simply mask it.
AirForceVet
Joined: Mar 2004
Posts: 602
Likes: 126
From: Spotsylvania,Virginia
DC doesn't mention the switching PSI. Some models are as low as 45 psi, which would be on the sensitive side of things. Even higher pressure switches of 120psi are pretty low.
Again, being sure of the electrics as described above by others and checking for residual pressure with the gauge as suggested will help eliminate guesses and assumptions.
I would caution against using a physical mechanical switch without getting to the bottom of the real issue. If there is residual pressure in your system, you want to correct that and not simply mask it.
Again, being sure of the electrics as described above by others and checking for residual pressure with the gauge as suggested will help eliminate guesses and assumptions.
I would caution against using a physical mechanical switch without getting to the bottom of the real issue. If there is residual pressure in your system, you want to correct that and not simply mask it.
AirForceVet
Joined: Mar 2004
Posts: 602
Likes: 126
From: Spotsylvania,Virginia
Well, it appears I had the adjusting rod adjusted to tight. I thought I had it adjusted properly, using my ohm meter connected to the switch, the brake pedal completely retracted I was getting continuity, I backed the adjusting out until I lost continuity then a tad more. So far everything is good. Thanks to all for their input.
