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disc brake conversion ????

Discussion in 'The Hokey Ass Message Board' started by mrbuck, Apr 19, 2013.

  1. mrbuck
    Joined: Nov 27, 2012
    Posts: 51

    mrbuck
    Member
    from nor cal

    so i just finished bleeding the brakes on the 58 biscayne for the second time. there are no leaks and no bubbles in the lines. i installed the front discs conversion from autocity classic, with 7" booster. the brakes work but i have to push the pedel down about half way before they start. and they work about as good as the old drums, i was expecting a huge differance. is there an adjustment on the booster or somthing im missing??:confused:
     
    Last edited: Apr 19, 2013
  2. philjafo
    Joined: Dec 22, 2012
    Posts: 42

    philjafo
    Member
    from right here

    Is the master below the floor? Residual pressure valves. What about a proportioning valve?
     
  3. mrbuck
    Joined: Nov 27, 2012
    Posts: 51

    mrbuck
    Member
    from nor cal

    the MC is mounted just insidee the firewall in stock location. the kit came with porp.valve how can i tell if it adjustable, how do i adjust it ? it seems that they should work alot better. the pedal is nice and firm when the car is of but once started the pedel will go 3//4 the way to the floor befor it feels like is doing anything. Ideals???
     
  4. dragonknucks
    Joined: Sep 27, 2006
    Posts: 136

    dragonknucks
    Member

    Is your pushrod within the m/c the correct length?
     

  5. The push rod may be too short. HRP
     
  6. mrbuck
    Joined: Nov 27, 2012
    Posts: 51

    mrbuck
    Member
    from nor cal

    the rod is adjustable,right, its the rod from the back of the MC that connects to the pedel. is there an easy way to extend it. can i just get a longer piece of all thread and replace it. does anyone know the correct demension
     
  7. BobMcD
    Joined: Jan 25, 2013
    Posts: 322

    BobMcD
    Member

    It's the pushrod between the master and booster, not between the pedal and the booster. You would need to remove the master cylinder from the booster. Measure the depth where the pushrod goes into the master. Then measure the distance that the pushrod extends from the booster and compare the difference. Should have a slight amount of clearance. Was the master cylinder bench bled before install? Also check the adjustment on the rear brakes. In my opinion there is still some air in the system.
     
  8. mrbuck
    Joined: Nov 27, 2012
    Posts: 51

    mrbuck
    Member
    from nor cal

    i didnt bench bleed the MC. do you have to do that? Ive got to assume the rod is the right one as they came together in the same ccp kit. ive bleed them twice and the second time got just a bubble or two out of one line the rest were all good.
     
  9. nickleone
    Joined: Jun 14, 2007
    Posts: 463

    nickleone
    Member

    autocity classic does not have a picture of your application on their website.
    If your master cyl has a rectangular block right off it with lines from the front bore and rear bore you have a non ajustable proportioning valve.
    Some of those valves need to be gravity bled. All lines at the wheels opened and let drain. The sliding valve in them will get stuck in one position or another when presure bled. Did not instructions come with the kit?
    Look up bleading procedure for any 70s 80s chevy with a proportioning valve and follow the instructions.

    Nick
     
  10. mrbuck
    Joined: Nov 27, 2012
    Posts: 51

    mrbuck
    Member
    from nor cal

    i did gravity bleed to begin with as i put new lines on so i figured gravity feeding ment a good time for a beer break. yeah i think it not adjustable too. its got front right and left and a rear bore.
     
  11. mrbuck
    Joined: Nov 27, 2012
    Posts: 51

    mrbuck
    Member
    from nor cal

    do i have to bench bleed or does it just make it a bit easier??
     
  12. BobMcD
    Joined: Jan 25, 2013
    Posts: 322

    BobMcD
    Member

    I always bench bleed first before I install the master. That way I am not adding more air to the system that will have to be bled out down stream. It also tells me if there is a problem with the master before I install it. I also had a thought about your front calipers. There is a left and a right. The bleeder screws should be at the top of the caliper. I have seen them installed on the wrong sides. If the bleeders are not at the top you will not get all the air out.
     
  13. mrbuck
    Joined: Nov 27, 2012
    Posts: 51

    mrbuck
    Member
    from nor cal

    i rebleed them one more time today for giggles and no air pockets. i did adjust the pedel to MC rod and it made it better not quit like a newer car but they stop fine so i think im good thanks for all your help
     
  14. classic gary
    Joined: Sep 24, 2009
    Posts: 504

    classic gary
    Member

    Are the calipers on the correct sides of the car?
     
  15. mrbuck
    Joined: Nov 27, 2012
    Posts: 51

    mrbuck
    Member
    from nor cal

    yeah there on the right sides
     
  16. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,263

    gimpyshotrods
    ALLIANCE MEMBER

    Bench bleeding is mandatory.

    Make sure that your REAR shoe drag is set properly. You'd be surprised what effect it has on the pedal feel, and travel.
     
  17. BobMcD
    Joined: Jan 25, 2013
    Posts: 322

    BobMcD
    Member

    A quick way to see if the rear adjustment is causing the low pedal is to set the parking brake and see if the pedal improves.
     
  18. MATACONCEPTS
    Joined: Aug 7, 2009
    Posts: 2,069

    MATACONCEPTS
    BANNED


    Bench bleeding is mandatory
     

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