1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

Rusty Brake Fluid In Recent Master Cylinder

Discussion in 'Early CJ5 and CJ6 Tech' started by kenny78, Jul 15, 2023.

  1. kenny78

    kenny78 Member

    Just looking for a sanity check. I replaced the single mc on the 65. The old one had the cap seized on.

    Upon removal rust colored fluid dribbled out. I had bench bled the new mc and did a rough bleed of the removed ?banjo? fitting. Figured I’d flush and properly bleed the lines the next couple of nights. The brakes were so improved that the next day turned into a month. Also mainly putting around the property with wife, dog, 1, 6, and 10 year olds.

    Opening the cap revealed heavily rust laden fluid. I sucked it all out and flushed the best I could with the “help” the little kids give. The question: Did the old fluid contaminate the new in the interim or did I pressure wash a lot of water in there before I realized(today) that there is a breather hole in the cap?

    Thanks
     
  2. wheelie

    wheelie beeg dummy 2024 Sponsor 2023 Sponsor

    I'd say that the old fluid contaminated the new fluid. That old rusty fluid was through the entire system and if you didn't flush it all out, it made its way back into your new master cylinder.
     
    Fireball likes this.
  3. Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    X2
     
  4. jeep peep69

    jeep peep69 Member

    Contaminated suck out fluid from master cylinder then refill with clean open the bleeder farthest from master and pull fluid through till clear with a vacuum pump . Do this on all wheels starting farthest working to closest.
     
    Fireball likes this.
  5. kenny78

    kenny78 Member

    Thanks fellas, this was my assumption but wanted to confirm. I might remote the vent through top of cap to help me sleep at night. I did suck out and flush, though will probably do again.