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master cylinder rebuild problem

Discussion in 'XJ Technical Chat' started by yamaman, Jun 10, 2010.

  1. yamaman

    yamaman Member

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    so I rebuilt my entire front brake system with new SS lines, both caliper rebuild kits, and a master cylinder rebuild kit and it didn't seem to push the fluid effectively enough. So I took it apart, snapped a pic, and want to ask if the parts are in correctly. the manual isn't clear enough. maybe the middle black part (to the right of the threads) is backwards? the flat part of the spring is on the right side in the pic above. It seemed right that the open part of the spring goes Into the MC since I think the solid end of the spring would block the exit of the MC. Thanks guys
    [​IMG]
     
  2. kcoop99

    kcoop99 Member

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  3. kcoop99

    kcoop99 Member

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    Well that link didn't work right but you can find the brake section....sorry!
     
  4. wizard

    wizard Active Member

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    That's all in the right order.
     
  5. kcoop99

    kcoop99 Member

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    Wizard, doesn't that cap need to have the smaller side sit on top of the spring, with the large part of cap on top of the piston???
     
  6. yamaman

    yamaman Member

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    thanks, well if it's in the right order the handle never has resistance, ever. I pushed it a million times. Here's what I did. at first attempt to prime the system or whatever you want to call it I put the fluid in the MC, pumped pumped pumped and seen tiny tiny air bubbles coming from one of the little holes, they actually took turns pushing bubbles, one then the other then the other etc.

    since the level wasn't getting any lower I hooked up a clear tube to the right caliper bleed screw, unscrewed 1 turn and put it into a clear bottle. Then unscrewed the MC banjo and pushed brake fluid through it with a syringe and needle until I seen fluid coming out of the caliper going into the bottle on the floor. Buttoned up the banjo and put fluid back in the MC. Pump pump pump and can see the fluid moving very slowly down the tube into the clear bottle but not fast at all. so I tried the left caliper, no advancement, never seen fluid come from that guy. So then I took it apart and posted that pic. I'm thinking the problem must come from the MC since there's no moving parts down the line (except for the piston) but I would feel resistance at that point right?
     
  7. yamaman

    yamaman Member

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    it's hard to see but that cap has a nipple in it that fits perfectly into the spring top. the spring top has a solid cap w/ a small hole - and that cap you're referencing has the nipple to go inside. the pic is hard to see it but if you look hard you can, that's why I put a flashlight
     
  8. RickCoMatic

    RickCoMatic Well-Known Member

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    The problem you are having might be elsewhere.

    Drain the Master and Look-IN ... Inspecting the walls of the Master Cylinder Bore.
    If the Bore i s scratched or looks ... "Pitted" ... the Seals might not build-up pressure.

    Aside from looking for Scratches and Pitting, ... look for the build-up of Foreign Matter.
    The light-gray build-up needs to be removed or the Seals won't develop pressure.

    Scrape it off with a sharp edge on the end of a BRASS Rod.
    Or, hit it with a Pencil Flame of a Butane Torch and it will turn to dust.
     

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