9" brake booster for 67 GS

Discussion in 'The whoa and the sway.' started by Gary Bohannon, Sep 30, 2021.

  1. Gary Bohannon

    Gary Bohannon Well-Known Member

    Can I replace my original 11" booster with a 9" and get the same angles, spacing and master cyl pocket etc?
    I have drum brakes front and rear.
     
    Last edited: Oct 1, 2021
  2. 12lives

    12lives You die once. You live every day.

    Good question! Are you replacing the whole assembly or just the booster?
     
  3. Quick Buick

    Quick Buick Arlington Wa

    FWIW when I was looking for a booster I noticed the 9'' booster is a single diaphragm..... The 8'' is a dual....

    I got zero input on the 9 ... the 8 feels very good.

    Advice make sure that whoever you buy it from state it fits A- bodys.... this style fits. https://www.ebay.com/itm/313546237785

    This style does not....https://www.ebay.com/itm/202250330046. Notice seller states fits nova & chevelle it dont.......
     
  4. Gary Bohannon

    Gary Bohannon Well-Known Member

    I just want a shiny new booster, but extra clearance (a 9 inch) for the valve covers is always handy.
    Just wondered if it's worth the trouble vs a stock replacement.
    Appreciate your opinions and advice.
     
    Last edited: Oct 2, 2021
  5. Gary Bohannon

    Gary Bohannon Well-Known Member

    "zero input on the 9"
    Do you mean the 9" had a weak boost for the brakes?
     
  6. Quick Buick

    Quick Buick Arlington Wa

    On Chevelles.com I read a few guys did not recommend using the 9''.... I also read that it felt like a cross between manual brakes and power....

    I do know that the 8'' works real good on my 67lark. I wish it had the braking power as my 92 caprice LTZ but those are 1/2 ton truck brakes to the best of my knowledge...... The 8'' was used on corvettes and F- bodies ..... I have no clue what the 9'' single diaphragm was used on.....Vega??????? guess
     
  7. Quick Buick

    Quick Buick Arlington Wa

    FWIW My car came to me with front disks and mixed up bunch of junk on the rear with the 12'' digging into the valve cover. With the rears as bad as the were I cant tell you just how the system worked...
     
  8. 12lives

    12lives You die once. You live every day.

    Bob - which 8 inch did you get?
     
  9. Quick Buick

    Quick Buick Arlington Wa

  10. Gary Bohannon

    Gary Bohannon Well-Known Member

    That looks good for 75 dollars. Any modification necessary?
    Did your pedal push rod fit ok? And did your master cylinder go back onto the original location?
     
  11. Quick Buick

    Quick Buick Arlington Wa

    Any modification necessary?=== bolted on with the 15$ brackets in post 3.....
    Did your pedal push rod fit ok?===== I lost my rod and clevis so I bought new like the 24.23$ in post 3... only to find out the brackets didn't work.. then I bought the 15$ bracket....
    And did your master cylinder go back onto the original location? Its not really in the same spot.. It looks a bit further from FW than stock, a Lot easier to put on than it was to remove old one... Angle looks more tilted.......MC bolted right on.. lines needed a bit of massaging...

    1 hour job was done... not including bleeding.... you may not need to bleed... I put the old power brake MC back on.....
     
  12. Gary Bohannon

    Gary Bohannon Well-Known Member

    You got a photo under the hood? Like to see how that looks.
     
  13. 12lives

    12lives You die once. You live every day.

    The dual diaphragm is much thicker so I doubt the original rod is going to work.
     

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