No Brake Pedal

Discussion in 'Other Auto Tech' started by clr0gers, Jul 2, 2014.

  1. I'm using the master cylinder & power booster as well as pedals cage from a 1985 Mustang GT for the brake system in my 1946 Ford pickup I'm also using a proportioning valve from a 73 to 76 F100/150. Everything else is new, lines, hoses, wheel cylinders, master cylinder, booster & all. My problem is this, I cannot get a good pedal no matter how many times I bleed the system. As a starting point in diagnosing the problem I removed the outlet lines on the M/C & blocked them both off, then I tried to pump the brakes but they are rock solid. I then hooked up just the front (which are disc) & got the same pedal feeling as before, nothing. I haven't worked much with proportioning valves before but could that be where the problem is or do I have another problem. I have disc on front with drum on the rear. I can bleed the system til I'm blue in the face but never get any more bubbles out of it, just clear brake fluid. If you have any ideas or experience in this area I would sure appreciate your help. Thanks

  2. Hiya Chuck. I'm not the resident expert on such things but I think that we have people here who can help.

    [USERGROUP=77][USERGROUP=77]@SN Certified Technician[/USERGROUP][/USERGROUP]

    Perhaps one of these guys can offer some insight.

    It sounds to me like a mismatched master cylinder and slave and/or booster.
  3. First question...what are the specs of the calipers on the truck?

    The master cylinder is a 21mm bore, which was paired with a set of 60mm single piston calipers.

    What size and how many piston are the front calipers?
    jrichker likes this.
  4. Make sure that all the bleeder ports on the calipers and wheel cylinders are mounted so that the bleeder port is the highest point that it can be mounted. Otherwise you may get air trapped in the calipers or wheel cylinders. If memory serves me correctly, the calipers will bolt up on either side, but if you use them on the wrong side, the brake bleeder isn't positioned at the highest point.