Register now to get rid of these ads!

Help with Brakes

Discussion in 'The Hokey Ass Message Board' started by HH Derrick, Mar 16, 2010.

  1. HH Derrick
    Joined: Jul 23, 2007
    Posts: 56

    HH Derrick
    Member

    Here is what I have: 68 Mustang Master Cylinder, 40 Ford front brakes, Chevy S-10 rear brakes, All new lines and new wheel cylinders. Master cylinder is under the dash.

    Here is my problem: I have rear brakes but very weak front brakes. I have adjusted the front brakes on the backing plates. When I bleed the front brakes Im getting fluid but the pedal does not give when you open the bleeder screw.

    I see that the 2 ports on the master cylinder are different sizes. The one on the back is smaller than the one on the front.

    Questions:

    1. Which port should I run the front and rear lines from on the master cylinder (exp. the front brakes on the smaller or larger port on the master cylinder)

    2. Do I need to have residual valves inline on the brake lines

    3. Just trying to figure out why thye are not working right......
     
  2. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,966

    V8 Bob
    ALLIANCE MEMBER

    You may have several issues. First, most under dash setups I've seen can have pedal force and travel losses through the necessary bell cranks and sometimes flimsy master cylinder mounting brackets. With both systems open, make sure the master is able to be full stroked before the pedal hits the floor, and that everything stays in place.

    Your rear brakes are more aggressive than the '40 Ford Lookheed fronts- not a good situation. You want the "good" brakes up front-always. I would upgrade the fronts to the later Bendix Duo-Servo design, like '48-up F-1/F-100, Lincoln, new aftermarket, etc. The '40 brakes are the least effective drum design and can be difficult to properly adjust.

    The port opening sizes on master cylinders have nothing to do with chamber size, they simply prevent the lines from being switched. If your master is drum/drum, both chambers will be visually the same size when the cover is removed, and the fronts can be connected to either. Disc/drum masters always have one chamber larger than the other. In ALL cases, the larger chamber, if equipped, ALWAYS goes to the fronts.

    You will have to check for internal residual valves, as some aftermarket or rebuilt masters do not have them, even if the original application did. A 10 lb valve should be installed to each drum axle if none are found in the master. The picture below shows the residuals-a paper clip or similar can be gently inserted into each port to verify if residuals are present.

    Bob


    [​IMG]
     
    Last edited: Mar 17, 2010

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.