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9" Drum Brakes - no wheel cylinder pressure

Discussion in 'Early CJ5 and CJ6 Tech' started by 65cj5-, Sep 7, 2008.

  1. Sep 7, 2008
    65cj5-

    65cj5- New Member

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    I have a 1965 jeep cj5 with four wheel 9" disc brakes. The jeep has been sitting for 7 years and has little to no braking power.

    I've cleaned out the master cylinder and bleed all four drums. I have my rear drum puller on order, but had the front drums off. With one drum off and someone pressing the brakes there was no cylinder movement pushing the brake pads on either of the front brakes. I pulled the dust boots off of the passanger side wheel cylinder and the pistons were coated in corrosion and brake dust since there was a crack in both dust boots. I tried PB and WD and baging on the pistons with a hammer to free them up and still nothing. The master cylinder appears to be applying brake pressure to the brakes and is not soft at all.

    My question is do I need to replace the wheel cylinders? Am I missing something else that might be causing the wheel cylinders to not apply pressure to the pads? Should I try and rebuild the wheel cylinders? If I order front wheel cylinders should I just order the rears as well?

    Any help would be appreciated:beer:
     
  2. Sep 7, 2008
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    If the wheel cylinders are corroded they need to be replaced. If they are corroded then most likely they are pitted and would at the very least leak when rebuilt. Brakes are a safety item, for the driver and passengers as well as the people around you. Don't skimp here.

    I'd also look at the condition of the hoses, hardware, and metal lines, and make sure the master cylinder is not leaking as well. Brake fluid is hydroscopic, which means it absorbs moisture. That's why brake systems corrode over time.
     
  3. Sep 7, 2008
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    replace all the wheel cylinders, it's just not worth the time & money trying to rebuild the old ones.

    Now would be a good time to consider upgrading the brakes to a dual master cylinder & 11" drums or disks, even when working 100% the 9" brakes are marginal & occaisionally very scary.

    H.
     
  4. Sep 7, 2008
    Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

    San Diego,...
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    :iagree: Wheel cylinders are not difficult to replace. If the corrosion is that bad it's not worth trying to rebuild them.
     
  5. Sep 29, 2008
    weedy

    weedy Member

    Conroe, Tx
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    I replaced all four cylinders, brake linings and hoses for less than $200. Make sure you turn the drums to ensure a good braking surface. Worth the time a $.
     
  6. Sep 29, 2008
    Steelwheels

    Steelwheels New Member

    Central Calif. Coast
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    Same here, after a 12 year sleep replaced the master cyl., wheel cyls., hoses, shoes, and drums. Now, properly adjusted, I can lock 'em up if necessary. And that reminds me, after a year and a half it's time to replace the fluid and bleed them.
     
  7. Sep 30, 2008
    weedy

    weedy Member

    Conroe, Tx
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    Everyone recomends discarding the 9" brakes but properly adjusted with good servicable parts they stop just fine. They are not nearly as powerful as the modern day disc/drum set ups but for normal driving and trail riding they are fine.
     
  8. Sep 30, 2008
    65cj5-

    65cj5- New Member

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    Got all new wheel cylinders, master cylinder, and flexible brake hoses. I'm not going to replace the hard lines, since I really just want to get it driveable. Weedy, I'm with you, I'm not running a V8 or heading to MOAB just yet so the 9" drums should be fine until I figure out my long term goal for the jeep. I also sort of like the idea of running the stock setup anyway, since this jeep is 15 years older than I am. I appreciate everyones advice.
     
  9. Sep 30, 2008
    Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

    San Diego,...
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    Sounds like a reasonable plan. Let us know how everything works out. Eventually larger drums should be considered just from a safety standpoint. 9" will get you by but you won't know you need larger brakes until you need them. ;)
     
  10. Sep 30, 2008
    weedy

    weedy Member

    Conroe, Tx
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    Yes, for the money you cant beat the stock set up. I am a moderate 4 wheler and I drive it on shrt trips around town (55mph and lower).

    It cost me about $200 to replace my stuff compared to $500-$700 to upgrade to 10" (I would have had to buy 4 drums).

    I did all rubber lines, wheel cylinders and new linings.


    Buy plenty of brake cleaner when you buy your parts.
     
  11. Sep 30, 2008
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
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    The biggest thing against the 9" brakes isn't so much the stopping power; For me it was the fact that no matter how hard I tried I just could not get them all adjusted evenly. The cam adjusters just don't lend themselves to precision adjustment IMHO, and I got tired of trying to predict which lane the Jeep would end up in on a hard stop. :shock:
     
  12. Sep 30, 2008
    dohc281

    dohc281 It is what it is.

    Laurel Springs, N.J.
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    I don't believe in taking the cheap route when it comes to tires and brakes. They are the two things that move and stop you. I got my last brake line hooked up on my conversion today to a dual reservoir master cylinder. I already did the 11" conversion a couple years ago.
     
  13. Sep 30, 2008
    Homebrew2

    Homebrew2 Member

    Dunlap, CA
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    THAT is great info! Thanks for posting it. I thought I'd run into every prob so far. I hadn't heard of the cam adjust to be a prob but will be sure to keep it in mind. :beer:
     
  14. Sep 19, 2009
    manganjb

    manganjb Member

    boston, ma
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    I'm also going to replace my rear master cylinders ... Does anyone know if I can just get the cylinders and the kits at a local store? Or do I need to buy them online ...
     
  15. Sep 19, 2009
    jglad

    jglad Village Idiot

    Glenville, WV
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    I would also replace all the steel lines too, especially if you are using the single chamber master cylinder. Brake fluid absorbs water and I have seen steel lines that looked good on the outside be rusted through from the inside. No brakes is not any fun.
     
  16. Sep 20, 2009
    cpt logger

    cpt logger Member

    Western Colorado
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    My local NAPA store has them in stock. Yours may need to order them, Usually they come in after about two day. I also would replace the steel lines (in stock at NAPA). Take your old ones down with you. Or at least measure the length of the old ones. Good Luck, Matt W.
     
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