Discussion in 'Shade Tree Mechanics' started by JD Martinson, Apr 9, 2017.

  1. JD Martinson

    JD Martinson Well-Known Member

    Finally got my '65 Wildcat back on the road after a complete brake system overhaul (New: Booster, MC, NiCop brakelines throughout, wheel cylinders. shoes, springs , etc.). But now I have what I believe is a vacuum problem.

    I have to gas the engine somewhat and wait for the pressure to build up in order to move the car, especially after using the brakes to slow or stop the vehicle. Additionally, there's a lot of brake pedal travel before the car begins to slow and or stop.

    On a side note, I took the advice of another forum use and after replacing the brake booster, I discarded the 1/2" rubber hose that ran from the back of the carb to the brake booster check valve, and replaced it with a 3/16" NiCop hard line using 3AN fittings. Is this part of my problem?

    Have I created a "vacuum problem" by doing so?

    What other things can I check to remedy my hesitation problem?

    Thanks in advance.
  2. buick64203

    buick64203 Buick Hunter Staff Member

    B y using 3/16" line, you've substantially decreased the tube size. What was the intended purpose in using 3/16" over 3/8"? Not sure I understand your statement that you have to have the pressure build up in order to move the car? Are the brakes locked up?

    You replaced a lot of components, so its going to be a little difficult to determine whats going on. I assume you have all the shoes adjusted up good so theyre dragging slightly on the drums?

    As far as the brake pedal travel, are you sure there isn't a mismatch between the booster pin length and the depth of the master cylinder piston hole? Be sure the hole in the back of the master is not too deep for the booster pin. If you have the old parts, check them against what you installed.
    SteeveeDee likes this.
  3. buick64203

    buick64203 Buick Hunter Staff Member

    And did you discard the check valve?
  4. Smartin

    Smartin Stainless Guy Staff Member

    I had a bad booster out of the box last year. Also bleed and rebleed the brake system....then bleed again.
  5. buick64203

    buick64203 Buick Hunter Staff Member

    Any update on this?

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