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Brake Lights Pressure Switch

Discussion in 'Builds and Fabricators Forum' started by FinoCJ, Jan 18, 2020.

  1. Jan 18, 2020
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2020 Sponsor

    Denver, CO
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    Replacing the MC in the wagon. The OEM single circuit MC has a Y-block/circuit splitter on the end that also accepts the pressure switch for the brake lights. Obviously, the new Willwood MC doesn't have a spot for the brake light pressure switch, and will need to figure out the best way to install one....
    Here is the old MC with integrated Y-blockswitch on the left end in the pic....
    [​IMG]

    I think I will need to plumb in a 3-way junction block that will allow the brake line to go 'through' using two fittings and put the switch into the 3rd fitting? Sort of like this set-up (although maybe I can get it from FLAPS a bit cheaper):
    Earls PK0017ERL Earls Brake Light Switch Kit - Pressure Activated w/ Tee

    Is this the best way to do it...or is there a better way. Does willwood make anything specific for their MCs that is a clean set-up?
    Last question....on the cj, I have 2 brake light switches: one on the front brake line circuit and one on the rear circuit (although I am not sure if the one on the rear actually works). Is it best practice to have a brake light switch on both circuits, or is it okay to run it on only one circuit?
     
  2. Jan 18, 2020
    Fireball

    Fireball Member 2020 Sponsor 2019 Sponsor

    Pullman, WA
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    Because of this article (that I saw linked from here some time last year):

    SW-EM Hydraulic Brake Light Switch Investigation

    You might want to change to a mechanical switch on the pedal linkage. This Chevy one is a popular option with the hotrod crowd: https://www.ecklerstrucks.com/chevy-truck-brake-light-switch-1955-1959.html

    As far as I know, most vehicles with dual circuits use a switch on the pedal. The also typically have a distribution block with it's own switch that lights up the "Brakes" light on the dash if a single circuit fails. The factory proportioning is usually built into the distribution block.

    Wilwood does make a distribution block, adjustable proportioning valve combo with a brake built in brake light switch. Not super cheap, but not super expensive either. It might be hard to fit under the floor, but it would allow you to adjust the front/rear proportioning if you upgrade to disks down the road.

    Wilwood Disc Brakes - MasterCylinder No: 260-11179
     
  3. Feb 6, 2020
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2020 Sponsor

    Denver, CO
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    So, still SLOWLY working on the brake MC...here is what I think I have ready to go....
    [​IMG]

    The rear brake line is 3/16 and I found a 3-way junction block at FLAPS....going to run a short section of tubing from MC fitting (needs a bend on the MC end to the junction block. Connect through to the rear brake line and put a pressure switch out the top with bullet connectors just like the OEM set-up. I am only going to run the switch on the rear line - for various reasons its easier to work this in on the rear line than the front.
     
  4. Feb 7, 2020
    47v6

    47v6 junk wrecker! 2020 Sponsor

    Washington DC.
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    I have had bad luck with the pressure switches. They seem to like to fail on me, so when I selected a set of swinging pedals i made sure to get ones that had a brake switch. Some people never have a problem with the pressure switches, mine was nothing but issues and i tried multiple different brands. All of them worked for a while.
     
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  5. Feb 7, 2020
    jeepstar

    jeepstar Active Member 2020 Sponsor

    Sheboygan
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    I've gone through 3 brand new ones in one summer. Try to find a better way
     
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  6. Feb 7, 2020
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2020 Sponsor

    Denver, CO
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    You guys may be right, and I just got lucky with the pressure switch I put in the cj - its been fine for 7 years. I also have the original (well lets say old) switch that is currently on the original MC - it was still working when I took it off - just the new MC doesn't have a place to install it. Maybe that old one is higher quality, and it can go into the junction block if needed....I don't really have any idea of a better solution given the through the floor pedals (and those are a must keep from my POV - same as in my cj). The current electrical situation is pretty sketchy so I don't want to go messing with it too much without a complete overhaul to an alternator and fuse box etc...so, this may be temporary because the switches fail, but if so, then maybe I will eventually get around to a better solution. In reality, if it fails, it didn't cost me anything except a few bucks for the switch and junction block...I still have to make some brake line connections, and even if it fails from a switch perspective, it won't require new brake lines etc. Instead of using a flare line union for 2 lines, I am using one for three and putting in the switch - its no additional effort and maybe it will work. And maybe, in short, I am just trying to get this thing back on the road...after this comes the radiator shroud...then its drive it and see if I want to keep it...I am starting to lean to getting in back on the road and selling it this spring....I am hesitant to invest any more time and energy into that I have already committed, which is too much....
     
  7. Feb 8, 2020
    colojeepguy

    colojeepguy Colorado Springs 2019 Sponsor

    At the foot of...
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    This.
    And this.
    I've tried multiple different brands (all "quality" units) and none of them last...I've resigned myself to replacing them every 3-4 months, and checking brake lights every time I drive the Jeep.
    If I was building a whole new system as you are, I'd try to work in a mechanical switch.
     
  8. Feb 9, 2020
    sterlclan

    sterlclan Member

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    47v6 likes this.
  9. Feb 9, 2020
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2020 Sponsor

    Denver, CO
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    hmm...have to see better how that works...the less connections in the fluid system the better as it always a PITA for me to get flare fittings to seal.
    FWIW...I ran into a problem with my previous solution...the 3 way junction block uses 3/16 flare fittings, but the switch uses 1/8 npt thread as they originally threaded into the MC...there are adapters, but it's just more connections. The earls kit posted above comes tapped correctly for this issue.
     
  10. Feb 9, 2020
    melvinm

    melvinm Member

    Arvada Co. 80003
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    I have used Painless # 80174 low pressure brake switch w/pigtail on both My M37 and My 1974 CJ5
    with no Problems .
     
  11. Feb 9, 2020
    ITLKSEZ

    ITLKSEZ Volvophilic

    Post Falls, ID
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    Then there’s this possibility...
    I’ve posted this before, but it’s relevant here. Ever since this happened, I’ll never use another pressure switch. I never considered this a possible failure point before. This was on my dirt bike, but it could just as easily happen in an automotive-style switch. Instant no-brake scenario when the pressure blew the top of the switch out.

    [​IMG]
     
  12. Feb 9, 2020
    sterlclan

    sterlclan Member

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    the lever is easily bendable and could be run with a spring or such as well, I used to have access to a few hundred of this type of switch but my son in law sold the whole lot of old parts .
     
  13. Feb 9, 2020
    supertrooper

    supertrooper Member

    moreno valley, ca
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  14. Feb 9, 2020
    jeep peep69

    jeep peep69 Sponsor

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    I welded a tab to the frame and installed a switch in it. Work very well with through the floor pedals.
     
  15. Feb 10, 2020
    Jeepsterjim

    Jeepsterjim New Member

    Lincoln, CA
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    Would you mind posting pics and such of how you did this up grade? thanks.
     
  16. Feb 10, 2020
    jeepstar

    jeepstar Active Member 2020 Sponsor

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    X2!
     
  17. Feb 11, 2020
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2020 Sponsor

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    Good point... brakes are truly a safety consideration - thus the reason for this project to swap out to a dual circuit MC. Am I correct in understanding that having a pressure switch in only one circuit, if it fails in terms of holding pressure (not just electrically) then only that one circuit completely fails, and the second circuit would still work to some extent...not ideal, but at least there is some amount of brakes...
    Maybe here is a different way to think about this... the oem system is by no means ideal - it was from the 50s - but it is a single circuit MC with a pressure switch in the MC and a difficult to check fluid level - a failure anywhere causes complete loss of brakes. I am trying to improve the system - so a dual circuit MC with remove reservoirs to easily check fluid level with a pressure switch is a big improvement. This sounds a bit grumpy, but compared to going back to the oem set-up...maybe its not about what is ideally the best set-up, but rather what is a reasonable improvement over what I have?
     
    Last edited: Feb 11, 2020
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  18. Feb 11, 2020
    ITLKSEZ

    ITLKSEZ Volvophilic

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    *to some extent* is a good way to put it. It’s never as good as you think it should be. :)

    Don’t let us stop you from using a pressure switch if that’s what you want. They’re not horrible, they just don’t seem as reliable as they used to be. Knowing that, if you have the option, put it in a place that’s easy to get to.
     
  19. Feb 11, 2020
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2020 Sponsor

    Denver, CO
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    sometimes its not about what you want, but about what you can do
     
  20. Feb 11, 2020
    ITLKSEZ

    ITLKSEZ Volvophilic

    Post Falls, ID
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    [​IMG]

    :D
     

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