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CAN"T get a hard pedal...need suggestions!

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by BobK, Jun 7, 2002.

  1. BobK

    BobK 1/2 ton status

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    CAN\"T get a hard pedal...need suggestions!

    I'v been chasing this problem since I've owned my 71 Blazer(2.5 years now).The brakes have never been good,very poor brakeing performance.

    I've done the following to this point:
    1-new front calipers with premium pads.
    2-Rotors are within specs so I just scuffed the surface with a medium sanding disc on my drill.
    3-made sure rear brake cylinders were moving freely.Lots of pad left on the shoes so I left them alone.
    4-adjusted rear brakes so there is only a slight drag felt when I turned the drum by hand.
    5-I adjusted the e-brake and that actually works great!
    6-new brake booster(there WAS a leak in the old one).That only made the brakeing easier(less pedal effort).Didn't improve performance though.
    7-new master-cylinder.bench bled it 1st before I installed it.(TSM says stock M/C provides enough pressure to rear disc's)
    8-new prop. valve.(for 4 wheel disc)
    9-bled the brake system umpteen times.Pressed the pin on the prop. valve while doing this.Also bled the brakes in the proper sequence.Started from the farthest wheel and worked to the closest.
    10-adjusted the rod that's inbetween the booster and the M/C.
    11-checked my vacume lines and checked how much vacume I had going to the booster.All is o.k. there.
    12-new stainless flex lines(all 3 of them)

    What's worse is I just converted to rear disc brakes and now the pedal is even worse(I have adjusted the rear disc e-brake,the pads are real close to the rotor.)
    I'll post pic's of the rear disc install on another post.
    Help me,I can't figure it out!
    Thanks
     
  2. Triaged

    Triaged 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    Damn! You have checked/replaced everything! You even checked the little stuff like the booster to master link!

    Only other things I can think of (don't feal insulted...grasping at straws!):
    Flex lines swelling?
    Bleeders pointing up (ie. calipers on the correct side)?
    Brake lines running too close to exhaust?
    Wrong bore size in the master (brakes would work good and soft...till you ran out of travel)?
    Bad Master? (it CAN happen?)
     
  3. BobK

    BobK 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    Sorry,forgot to mention...new stainless flex hoses(all 3).
    Lines are in stock positions(tight against the frame rail on the passenger side).
    Bleeders are faceing north.
    Bad M/C is a possibility!
     
  4. chevyracing

    chevyracing 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    Bob,
    Maybe a parachute would help. ;-)
    John
     
  5. BurbinOR

    BurbinOR 3/4 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    Power bleed that system..........have it done by dealership or 4x4 shop.............had it done and what a difference.
     
  6. lukefalls

    lukefalls 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    This is a dumb question, but I have to ask. What does it matter which direction the bleeders are pointed? I am having problems with a clutch system, but the bleeder is poined south. Is that a big prob?
     
  7. Chris_T

    Chris_T 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    I'd say have it power bled as well, it can't hurt and it also gets rid of any water logged fluid in the lines. I chased a soft pedal in my '72 with multiple bleedings after I changed my master cylinder (leak) and couldn't believe how much the pedal firmed up after having it power bled.
     
  8. BobK

    BobK 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    Bleeders need to face up when bleeding only.Otherwise they can face any direction you want.

    So far it looks like I'll be getting it power bled next week.Hope it helps.Those who have had it done,how much did it cost.
     
  9. lukefalls

    lukefalls 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    Thank You! I am an idiot, but thats ok. I have been trying to figure out why I cna't get the hydrolics to work. I now see that I had the slave upside-down. Thank you. Good luck with your brakes.
     
  10. Steve_Chin

    Steve_Chin 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    The first problem with the Cadillac calipers and TSM's kit is that their brackets are made for GM mid-size front calipers and are only a ghost-fit for the Cadillac calipers. This makes the bleeders on the rear calipers not point in the correct direction and traps air in the calipers. You *must* remove the rear calipers and manually bleed them with the bleeder screws pointed straight out the front of the Blazer (this puts the bleeder passages in the top of the caliper's cylinder). Power bleeding won't make a bit of difference with this setup unless you've repositioned the calipers so that the bleeders point straight out the front of the Blazer.

    Other than that, I'd have to say that you have an internal leak in your master cylinder. If your pedal gets better for a while after you bleed then gets bad and you can't find a leak, it's the master.
     
  11. BobK

    BobK 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    Steve,I did take the calliper off the mounting plate when I bled them.The bleeders were pointing north during the bleeding process.
    I vacume bled them,I reverse fluid injected them(tool that you can bleed the brakes from the brakes back to the M/C) and finally I gravity bled them.
    I went to your site and copied your write-up on the disc conversion.It helped greatly Steve,thanks.
     
  12. 70~K5

    70~K5 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    You know most of these are older trucks now maybe a little Viagra in the MC would give you a firm/ hard pedal. /forums/images/icons/smile.gif ROTTFLMAO
     
  13. BobK

    BobK 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    LOL...that's funny...haven't tried that yet though.
     
  14. mkmiller

    mkmiller 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    I'm having the same problem with my '71. Only I have rear drums. After I put the new calipers on and got everything bled the drivers side one is loose with no pedal pressure and the pedal goes all the way down just barely giving me enough pedal to get stopped quickly. I haven't replaced the master cylinder but that is the only thing(other than hardlines). My sitituation sounds exactly like yours.
    Matthew
     
  15. NITRO

    NITRO 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    ive got a '79 and i had the exact same problem, so i replace the MC when it started leaking. so i went to autozone and bought another one with lifetime warranty for $13. well that one started leaking 3 days ago. so i went back and got another one. this time i got a really nice one. (it all depends on what u get cause they are rebuilt cores.) and this one has bleeders on the mc itself. finally this one works great. i guess it was just a F*cked up MC .

    NITRO
     
  16. m j

    m j 1/2 ton status

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    Re: CAN\"T get a hard pedal...need suggestions!

    are you refering to hydro clutch?
    if so the slave has to be pulled from bracket and held at an angle to get it to bleed.
     

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