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Brake problems

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by newyorkin, Oct 2, 2001.

  1. newyorkin

    newyorkin 1 ton status

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    Last night driving home, my pedal got a little soft. Then a little softer, and a little softer, so I made a mental note to fix it this weekend, forgetting that this was monday... This morning, I get in to go to work, and at the first corner, I hit the pedal to stop at the stop sign, the perty little red light comes on in my cluster, and the truck slows down, but will not stop... Being super late already, I drove to the train station pumping the pedal the whole time (probably pumped it all out on the way).

    I haven't checked anything out yet, but I'm suspicious of the right rear wheel cylinder, since I had the drum off 3 days ago and adjusted it (it was the only one that was touched, that's why I suspect it so far, no other reason). I haven't seen any leakage anywhere, but I haven't really looked yet...

    If it is the wheel cylinder, you guys think I should do the master cylinder too, since I'll have to bleed it anyway? I've heard that old MC's will fail shortly after bleeding the system (I think in one of Dyeager's posts or somewhere on here) since the piston gets over-extended during bleeding.

    Ratch
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  2. Pugsley

    Pugsley 1/2 ton status

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    While it's probably not necessary, it's one of my personal habits to replace the master if I replace wheel cylinders or calipers.

    Of the 5 toughest dogs in the neighborhood, my cat's ranked #3
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  3. taterblazer

    taterblazer 1/2 ton status

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    If it\'s old..

    If it's old I would replace it at the same time as you do the other brake components. Have to bleed the system anyways. As far as newer ones go I haven't had any problems with keeping the same MC. All new brakes on my 88.
     
  4. newyorkin

    newyorkin 1 ton status

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    Re: If it\'s old..

    aye, mine's an '88 also. I'm just figuring if it's cheap enough, would it be worth while...

    Ratch
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  5. taterblazer

    taterblazer 1/2 ton status

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    If you got the $ do it.

    I'd do it if you have the $$. I don't regret redoing my front and rear brakes. Cylinders, drums and calipers. Gives me some peace of mind. Brakes are important!
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    All you have to do is check the MC to see what the problem is. You could have just lost the MC seals anyways. if the fluids gone out of one reservoir, you know what happene, and you'll know if its front or back.

    I wouldn't replace the MC just because you do the wheel cylinders. But I'd prolly buy an MC while you were at the parts store picking up whatever other brake components you need to replace, to have it ready. If you can't get the pedal "firm" after replacing, say the wheel cylinder and bleeding the brakes to eliminate that problem, I'd throw on the new MC. You do NOT have to bleed the brake system when you replace the MC, per the MC instructions I had. Plus I did it that way, and it's fine.

    I'm a big fan of replacing only whats failed or what you know is going to fail in short order. (everything gonna fail sooner or later) There is no guarantee the MC will fail after bleeding the brakes. But if its never been replaced, and the fluid looks like engine oil, you probably have just cause to replace it, or will shortly. Mine lasted a few weeks after bleeding, before it actually started to fail to stop the vehicle, but I was lucky that it was just sitting at stop lights, not on the freeway. Just don't forget where your e-brake is ;)

    Dorian
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  7. newyorkin

    newyorkin 1 ton status

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    Well, I certainly won't forget where the E-brake is!! It's all I had getting home tonight!

    I pulled out a few feet at the train station when I got home and found a little trail going from behind the left-side rear wheel to where I moved it to.

    I don't think I"ll be doing the MC tonight... $150 new, $50 rebuilt. 5 years ago, it was $25!!!! The guy at the parts place said I'm paying for it's age...

    You can always tell where I parked at the train station... There's the NP208 ATF drip, rear pumpkin drip, power steering box drip... Now wheel cylinder drip...

    Ratch
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  8. TorkDSR

    TorkDSR 1/2 ton status

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    it doesn't make sense... one wheel cylinder will only destroy have, the brakes. but it should get bad, and then stay that way, not get worse. you should still have your front brakes, and if you don't then i would look further into the brake system.

    Tork DSR
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  9. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Your truck is just marking its territory...[​IMG]
    I was told to put a 2x4 or something under the brake pedal when bleeding to prevent ruining the seals in the MC. There is no need to pump the pedal all the way to the floor to bleed the system.

    Rene

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  10. newyorkin

    newyorkin 1 ton status

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    Good idea on the 2x4.

    TorkDSR, you're right, that wasn't right... I did have front brakes, but they seem to be extremely weak, so I was going on the parking brake first, then easing the fronts on.

    It turns out my brake line that runs along the axle tube is smashed (I thought it a little odd the point it was dripping from, but just figured it was running down the line frm the wheel cyl somehow then dripping.)

    It's in a really wierd place, sort of an inch in from the shock mount, so almost protected. It's like someone hit it with a hammer a couple times. There's no other visible damage but that popped brake line. Really wierd...

    Oh well, project for tomorrow night now...

    Ratch
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  11. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I once had a MC develop an internal bypass that left me with no brakes at all in 3 applications. Fortunately I was on my way home and it was almost 3 am with no traffic obviously. Using my emergency brake showed me that my rear brakes were mechanically inoperable as well. Two problems came together to scare the crap out of me. My truck is a 4 speed so for braking I'd shut down the motor and use the compression braking to bring it to a halt. Not very safe or fun but I only needed to do that twice before I babied it into the driveway.
    I've also had a brake line rupture in the rear due to corrosion. Needles to say I went through my brakes top to bottom and front to back. Expensive but worth it.

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
     

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