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Dam brake light..

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by NoSmog73, Dec 2, 2002.

  1. NoSmog73

    NoSmog73 1/2 ton status

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    What would be the most likely reason that the brake light comes on when you stop...
    1.The fluid is full...But could stand to be changed
    2.New brakes in the front..But like to squeak...LOL

    I have a new brake light switch to put in and a new flasher Because I for some reason keep losing the drivers side brake light but I have the running light...
    Thank you for any idea's...Mike
     
  2. 87sm465np208

    87sm465np208 1/2 ton status

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    well if its coming on when you stop.... maybe its doing that because your putting your foot on the brake, and that in turn sets off the brake light switch /forums/images/graemlins/shocked.gif. theres a thought /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif.

    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/truck.gif
     
  3. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    </font><blockquote><font class="small">In reply to:</font><hr />
    What would be the most likely reason that the brake light comes on when you stop...


    [/ QUOTE ] I think that everyones brake lights come on when they stop. /forums/images/graemlins/shocked.gif
     
  4. Tweetysuarus

    Tweetysuarus 1/2 ton status

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    Hey NoSmog if your master cylinder has low fluid level switch on it or near it you might have to bleed the master over again or just replace the switch. I had the same issue on a 72 CST Blazer before the DASH BRAKE WARNING LIGHT came on every time I pressed the pedal. Also check the brake light for a short if you have a bodylift or have removed and reinstalled your tail gate!
    Bill
     
  5. NoSmog73

    NoSmog73 1/2 ton status

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    </font><blockquote><font class="small">In reply to:</font><hr />
    I think that everyones brake lights come on when they stop

    [/ QUOTE ]

    Ok smart ass /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif I was taking about the round light on the lower left corner of the dash that says brake on it...It stays on all the time now ...LOL j/k
    I started to think when it first came on and the only "wire" hook-up That I can think of would be the brakelight switch ...Did they put "other wires" on the master cyl. that I can not see....
    I am getting ready to put the 14 in with the disks and was hoping to fix it before that goes in...I will change the brake light and see if that helps...thanks
     
  6. Tweetysuarus

    Tweetysuarus 1/2 ton status

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    By the way 4x4High! that said:I think that everyones brake lights come on when they stop
    ! So point that HA!HA! elsewhere!
    There should be a low fluid level switch on or near the master cylinder maybe on the porportioning valve. singal switch all by its lonesome! And yes I was refering to the Low fliud level warning light Not the lights out back. although you did say turn signal was fine but no brake light?
    Bill
     
  7. NoSmog73

    NoSmog73 1/2 ton status

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    My bad bill...I have 2 problms with them..LOL

    the first is the light on the dash staying on and the 2nd is that the rear driversside brake light seams to not work most of the time and I am not getting power to the connection at the firewall , But I have the running lights and no turn sig on that side...LOL
     
  8. imiceman44

    imiceman44 1 ton status

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    If you replaced the front pads, and are sure the fluid is not low, and no air in the MC, then check your rear brakes, adjust them closer to the drums, I had the sme problem, with a hard brake the light comes on and stays on, untill I either pump the brake or go uphill and brake.
    The problem is the shoes are too far so the pistons go out tto much to push the shoes on the drum, that creates a big flow to the back which triggers the light. /forums/images/graemlins/thumb.gif
     
  9. 87sm465np208

    87sm465np208 1/2 ton status

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    my wrong, didnt mean to be a smart ass /forums/images/graemlins/wink.gif, but i didnt get your explenmation. that is the brake purposioning vlave switch, means somthin an't right, or your parking brake is on, once mine went on and didnt go off and i got scared, turns out the parking brake petal wouldnt stay up, so i zip tied it to the dash /forums/images/graemlins/grin.gif. but id check it out, sorry again about being a smart ass, but i thought you were acctually having a problem with the brake light acctuator switch. /forums/images/graemlins/smirk.gif. /forums/images/graemlins/thumb.gif

    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/truck.gif
     
  10. NoSmog73

    NoSmog73 1/2 ton status

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    I know then it is the rears ...That is the reason for getting the 14 it was cheaper in the long run to do then buy new crap for the 12 bolt I will change the axles and see if that helps...Thanks bill
     
  11. Triaged

    Triaged 1/2 ton status

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    The reason the idiot light comes on is because you have lost half of your brakes! /forums/images/graemlins/shocked.gif

    Don't drive it if that happens!...would you drive your truck with the oil light on?

    The first things I would check is the rear wheel cylinders. You have to pry back the dust seal and see if any fluid leaks out. If they are fine I would have to say master cylinder but it could be alot of other things.
     
  12. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Lost pressure in the rear like Triaged thinks. Either that or the Combination valve just fried. Somebody else just recently had a bad CV.
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    If you are getting half your brake lights (external obviously) then don't waste your time on a brake light switch. They work in tandem, so obviously if one brake light works, the switch isn't the problem.

    If the fluid is bad like you mention, and you decide to change it/bleed your brakes, you may lose the master cylinder as well, so just be prepared for that.
     
  14. 87sm465np208

    87sm465np208 1/2 ton status

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    ok, i dont understand why you would loose the master cyclender if he bled his brakes, ive never heard of this, please explain. /forums/images/graemlins/thumb.gif

    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/truck.gif
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    The longer the system is left without changing fluid, the more crud builds up.

    Since the piston(s) in the master cylinder, when operating correctly, only travel X depth into the master cylinder bore, the crud will build up on the walls PAST that point, as well as corrosion. When you bleed the brakes, you force the pistons further into the bore, right into all that crud/corrosion.

    If you are lucky, nothing will happen. In my case, and many others, the seals are ruined, and you can't get a firm pedal back. It stays spongy, with excessive travel. Eventually you'll be sitting on a hill, and the brake pedal will go to the floor, the brake light will come on, and you'll start rolling forward as you lose pressure.
     
  16. NoSmog73

    NoSmog73 1/2 ton status

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    Wow thanks for all the Good replys now at least I have a starting point to start from..Just need to drop the 14 in first...then get the brakes going right...Again thanks for the good idea's...Mike
     

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