Leaking Master Cylinder- Options?

Discussion in 'Suspension, Steering, Brake & Wheel Topics' started by dadgonebroke, Jan 25, 2018.

  1. dadgonebroke

    dadgonebroke Veteran Member

    Jul 1, 2008
    Nature Coast of Florida
    I've had my '72 RS Z28 for two years now and the brakes are and have been mushy and as I checked the reservoir this week again, front side is down 1/3 and the rear side is almost empty. As the car is pretty much original, what do you guys recommend for remedies? Send it out for rebuild- buy new or what?
  2. 70-camaro

    70-camaro Veteran Member

    Mar 25, 2010
    marietta ohio
    Have you seen any leaks? Fluid has to be going somewhere. If you are concerned with originality you can have the original MC rebuilt. It may be time for new lines, hard and soft. Old rubbers lines can cause mushy pedal too but sound like fluid loss somewhere.
  3. BonzoHansen

    BonzoHansen Administrator Lifetime Gold Member

    If the master is leaking then get a new one or rebuild your old one. I'd verify that first. not sure about originality or if those are date coded, or any of that stuff or if it matters to you.
  4. dadgonebroke

    dadgonebroke Veteran Member

    Jul 1, 2008
    Nature Coast of Florida
    I can see fluid running down the firewall at the base of the MC. If the MC is date coded, I'd be interested in rebuilding. If not, an exact replacement would be my next choice.
  5. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

    Nov 4, 2004
    Ringgold, GA
    Mine did this several years ago, vacuum booster was soaked also. I replaced both, wasn't concerned with originality, but they both can be rebuilt and brought back to original finish/appearance.
  6. COPO

    COPO Veteran Member Lifetime Gold Member

    Sep 15, 1999
    Ontario, Canada
    Rebuilds are not guaranteed to last from Napa so then why bother rebuilding it. For $5 more, I purchased a new one from Napa and put my orig in the box.

    My brakes haven’t been this great for all the 37 yrs I’ve owned it.
  7. Gary S

    Gary S Administrator Lifetime Gold Member

    Apr 14, 1999
    Bismarck, North Dakota
    I did the same thing. My brakes got weaker and weaker over a few years until the master cylinder failed completely. I put the old one in a box and installed a new one. The brakes are great again.
    My concern with rebuilding the old one was that by the time they are this age and fail, it usually means that the bores are corroded. Honing and rebuilding will leave you with an unreliable master cylinder. To get back to factory quality, it would require boring and sleeving the body and that could easily cost more than it is worth unless originality matters a lot.
  8. BonzoHansen

    BonzoHansen Administrator Lifetime Gold Member

    Agreed with what Gary said. Put a new one on it like Mark said and keep your old one in a box just in case
  9. Zspoiler

    Zspoiler Veteran Member

    May 6, 2012
    Federal Way, Washington
    i agree put in a new one with a warranty.
  10. dadgonebroke

    dadgonebroke Veteran Member

    Jul 1, 2008
    Nature Coast of Florida
    Ok- new it is. Where do I go for an original looking MC? Will the NAPA fit the bill or somewhere else? Just because they have a lot of choices, I checked RockAuto and it seems Raybestos has a lifetime warranty and AC Delco is only 1 year and both are only about $20 which seems awful cheap! I went to the NAPA site and rebuilt units are $77 while new ones are $37. Why is rebuilt more expensive than new?
    Last edited: Jan 25, 2018

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