Results 1 to 6 of 6

Thread: brake master cylinder + booster

  1. #1
    Junior Member
    Join Date
    Jul 2009
    Posts
    13

    brake master cylinder + booster

    Hi,

    i have a fiero brake booster with wilwood aluminium tandem master cylinder.
    but my brake pedals need a long way.

    between the booster and the master cylinder is a bolt. i constructed a longer custom bolt.
    now i press the pedals a little bit and the car stop (that's perfect). with this construction i can drive all the day.

    problem:

    next day i start the car, but i can't drive because the brake is pressed alone. first when i unsrew the master cylinder i can move the car.

    What is the problem between the master cylinder and the custom bolt?

  2. #2
    Senior Member
    Join Date
    Feb 2005
    Posts
    109

    Re: brake master cylinder + booster

    It sounds like you may need to bleed the brakes some more. Did you bench bleed the master cylinder before installing?

  3. #3
    Senior Member
    Join Date
    Apr 2010
    Posts
    398

    Re: brake master cylinder + booster

    Make sure that the pin between the master cylinder and the booster is not too long. The piston in the master cylinder has to completely return to the stop or it might not release the pressure on the brakes.

  4. #4
    Junior Member
    Join Date
    Jul 2009
    Posts
    13

    Re: brake master cylinder + booster

    i bench bleed the master cylinder and bleed the complete system.
    when i make the pin 5 mm longer, i can brake perfect all day day. but next day i can't move the car.

  5. #5
    There should be an air gap between the pushrod and the master cylinder piston. To test to see if you have this air gap, remove the master cylinder reservoir cover so you can see the brake fluid. Now hit the pedal. You should see a shot of fluid go straight up out of the master cylinder. If you do not see the fluid shoot upward it is too tight.
    The master cylinder piston must return to the top of its stroke every time the pedal is released or else the heat of the fluid at the calipers will start to apply the brakes slowly.

    What you have done is cranked the pushrod to simulate pressing the pedal down so now you would only need to press it a short distance.
    If your pedal stroke is still too long check for air in the system and sticking or misaligned brake calipers. It could be your Tilton pedals have the pivots in the wrong spot.

    Did you setup your balance bar correctly between front and rear master cylinders?
    Your center point should be much closer towards the front master and not in the middle.

  6. #6
    Senior Member
    Join Date
    Apr 2010
    Posts
    398
    His post says he has a tandem master cylinder rather than dual master cylinders so the balance bar issue will not apply in this case. I still think, as you said, that he has the rod between the booster and the cylinder too long. Also check and see that there are no residual pressure valves for drum brakes in the system. Some of the Wilwood master cylinders come with them. If the brakes are locked up, jack up each end of the car and see if the front or rear is locked or both. That will help pinpoint the problem. It helps to have a return spring on the pedal itself.

Similar Threads

  1. Clutch/Brake master question for murci-style kit owners
    By Whitey078 in forum Technical Discussion & Question
    Replies: 9
    Last Post: 08-23-2011, 11:44 PM
  2. Brake booster... Alternative options?
    By giveitup2me in forum Build Diaries
    Replies: 1
    Last Post: 08-21-2011, 01:29 AM
  3. Converting a 4 cylinder into a V-6 ?
    By g_ogata in forum Technical Discussion & Question
    Replies: 3
    Last Post: 09-02-2004, 06:44 AM
  4. Brake Cylinder Help
    By janice_ho in forum Technical Discussion & Question
    Replies: 0
    Last Post: 11-12-2002, 10:54 AM
  5. Remote Master Cylinder Resevoir
    By zrthompson in forum Technical Discussion & Question
    Replies: 3
    Last Post: 10-01-2002, 03:54 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •