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brake question

Discussion in 'The Hokey Ass Message Board' started by chainsaw, Mar 15, 2014.

  1. 62 t bird, power drum brakes. The pedal is slow to return, especially in slow moving bumper to bumper traffic. It returns faster if taking off from a stop light . I put a return spring from the pedal to a bracket under the dash and now it works great at all speeds. Question is, did I fix the problem or just band aid it for awhile.
     
  2. If the master cyldr. and brake system are all in good and correct woking order, I would say you solved the issue.
     
  3. Getting the pedal up is great !
    The thing you really want to make sure of is that the brakes are releasing.
    The master is returning and your pushrod stays attached.
     
  4. In bumper to bumper traffic you could feel the brakes dragging pretty bad, had to pull the pedal back with my toe to get them to release. From a stop they didn't drag, I guess the vacuum to the booster helped. With the return spring they don't drag at all. Wondered if the booster or mc was starting to go bad, hard to believe a spring would fix the problem.
     
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  5. Check the pushrod is not binding at the pedal .



    .
     
  6. Hnstray
    Joined: Aug 23, 2009
    Posts: 10,882

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    I think you have a problem in the booster or a vacuum valve. It sounds like you have vacuum being applied to the booster at a low level on a continuous basis and that is why the pedal wants to stay down. On acceleration the manifold vacuum drops and the booster isn't applied and the brake return springs are sufficient to release the brakes. If the master cylinder was at fault, the change in manifold vacuum would not change the condition.

    In my opinion, with that spring you installed, you are treating the symptom, not the cause.

    Edit: it may be that you do have a pedal return problem which was causing the booster to be "lightly" applied and the return spring you added compensated for that. Even if that is the case, finding and correcting the initial problem might be best. All that said though, I still suspect the booster. Best wishes
     
    Last edited: Mar 16, 2014
  7. saltflats
    Joined: Aug 14, 2007
    Posts: 9,644

    saltflats
    Member
    from Missouri

    I believe the booster has a large return spring in it. And the piston in the master doesn't have a way to hold the push rod in so pulling the pedal up would not pull the piston back so the pedal or the booster must be the problem.
     
  8. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,512

    V8 Bob
    ALLIANCE MEMBER


    I don't remember ever not seeing a pedal return spring in the vehicles I've worked on, both manual and power. Normally, the master cylinder and booster internal springs are only designed to return their internal parts (pistons, diaphragms etc), not pedals and related linkage. All pedals, both clutch and brake, should always have their own return springs on custom installations, imo. :)
    Booster push rods are normally integral with the control valve and cannot be pulled out of the booster. Manual push rods are either retained in the master cylinder primary piston, or they are positioned deep into the counter bore to prevent falling out if they return faster than the piston.
     
    Last edited: Mar 17, 2014

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