Broken Master Cylinder Stud

Discussion in 'Other Automotive Tech & Talk' started by DAB, Jan 21, 2012.

  1. DAB

    DAB MAVERICK/COMET ENTHUSIAST

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    Well, everything was going smooth yesterday on my '69 T-Bird brake repair until I broke one of the mounting studs for the master cylinder! (One of the 2 studs that mounts the master cylinder to the power booster). This was just before dark last night.

    I've got about 1/2 " sticking out so I could tighten 2 nuts against each other and try to turn it out of the booster, but I bet it's solid rust....and really not enough to engage full threads on both nuts.

    Before I do this, though, I'm wondering if the studs are pressed into the booster from the inside. On the non-power brake cars, the studs are threaded into the firewall, but on the booster you have to keep a vacuum, so they may be mounted differently.

    Anyone got any idea how they are mounted?
     
  2. jmgford

    jmgford Member

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    Doug,

    According to my 1969 shop manual, they are pressed in from the back. Sorry.
     
  3. DAB

    DAB MAVERICK/COMET ENTHUSIAST

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    Thanks.....that's what I didn't want to hear! lol

    I wonder if the wall is thick enough to thread and seal with locktight if I were to drill it out and tap it.

    I don't have much to loose at this point----maybe the core on the power booster.
     
  4. jmgford

    jmgford Member

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    Any that I have seen are just stamped sheet metal. Any chance of welding a stud to the broken part?

    Most of those boosters can be separated and re-assembled. It's time consuming, but it may be the best fix in the long run.
     
  5. DAB

    DAB MAVERICK/COMET ENTHUSIAST

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    I thought about welding onto the stud, but I would be concerned about putting heat on the booster and it's old, brittle diaphragm.

    Well, buying a re-manufactured booster and master cylinder assembly was an option, and as typical, I went for the cheap route. I really think at this point, I might as well replace the booster, since after all, it's 43 years old and rusty. I could get that re-manufactured master cylinder on there today and the old booster would leak next week! lol
     
  6. jmgford

    jmgford Member

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    Probably the wisest, but I would have tried the cheap route first, just like you did. Best of luck with it, whatever road you choose. :)
     

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