Hard Pedal, No Brakes F100

Q.

I have a 1962 Ford F100 with a new master cylinder installed. No leakage. All manual drum brakes. No booster. Hard brake pedal but NO fluid going to wheel cylinders even with bleeders completely removed on all 4 wheels. I can’t bleed the brakes. Any suggestions? I have bled many brakes in prior years on various vehicles, but never encountered this. This truck has set for 3years before I recently purchased. Thank you for any assistance.

A.

Assuming you still have the original single reservoir master cylinder, I suspect there is either a clog in the line before the splitter or a clog in the splitter or your new master cylinder is faulty (it happens, even with new parts). I would start at the master and loosen the line fitting, put on safety goggles wrap a rag around the fitting and have someone press the brake pedal. If fluid is present and the pedal travels to the floor then the culprit is likely a clogged line. Then loosen the line at the splitter and repeat fluid check process then check the lines as they leave the splitter. We are only trying to discover the source of the obstruction at this point and not concerned with bleeding the system.

At this point you should have a good idea of where the problem resides, clean and/or replace the affected component then proceed with bleeding the brake system.

I recently encountered a similar problem on a 1968 Cutlass. The car had been converted to a dual reservoir master cylinder at some point and the owner complained about a lack of brakes, although the brake pedal was hard. We went to bleed the rear brakes and no fluid was present and even with the rear bleeders removed we still had a hard pedal. The Master Cylinder was only a year old, so we found it hard to believe it could be the source of the problem… but we removed the line from the master, held a rag over the open port (wearing safety goggles) and had someone press the brake pedal to determine if fluid was passing through the master. To our surprise we still had a firm pedal and only a drop or two of brake fluid came out of the port. We replaced the master cylinder then everything worked perfectly.

Wrench Safe,
-Mark

Discussion
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12 Responses to “Hard Pedal, No Brakes F100”
  1. T grassl

    Remove lines at master and blow hi pressure air backwards on lines at the wheels cleans out lines

    Reply
  2. David J Mahoney

    Starting at rear and working forward, disconnect each line at each fitting and use a blow gun and blow towards the front, until you find the plugged line. Fix or replace then flush system.

    Reply
  3. mark

    Have you replaced the flexible brake hoses? I have had them rot shut inside and look fine from the outside.

    Reply
  4. Bill Storer

    You might also want to check the rubber brake lines (flex lines) that go to the wheel cylinders. I have a 1965 F100 and a 1964 1/2 Mustang convertible. These also displayed the exact same symptoms you are describing and to no avail everything else was fine except for inconsistent brake fluid at the wheel cylinders. Come to ind out that the rubber lines after years of use break down inside the lines and swell up restricting the brake fluid from reaching the wheel cylinders. You still have a hard brake pedal because the break fluid is not flowing to the wheel cylinders. After I originally replaced the rubber lines on the Mustang (the first one to do it) I took it out for a test drive and it about put me through the wind shield because they worked extremely well then! The same thing applied to the F100 after doing it as well. Don”t forget to also check the one rubber line in the rear as well because if that is bad to you will only have good brakes in the front. Hope this may help you as well. Good luck.

    Reply
  5. Dick

    1930 Model A 2 door sedan. Can lap belts be put in or shoulder belts ? Can I put in a crossbar on dashboard passenger side for something to hold on to ? Thank you kindly.

    Reply
    • Customer Service

      Hello Dick,

      Yes, Lap belts can be added to your Model A, you’ll want to reinforce their mounting points on the floor.

      A shoulder belt, can be added too, but to be truly effective it will require significant reinforcement to the B-pillar and tied in to the body structure.

      Grab bar… Sure why not… but I am not sure you need it for routine classic car driving. I am not entirely sure how it is tied to the structure of the rest of the body, as I have never done one, bur it may need to be attached to a mounting bar behind the dash that anchors top the A-pillars.

      Wrench Safe,
      Mark CCRC Video Membership

      We’d love to have you be a part of our community. We are convinced you will enjoy the benefits of becoming a member and having access to the best instructional how to videos and professional tips. We would like to offer you a special promotion for your first year membership.
      http://go.ClassicCarRestorationClub.com/C9938

      Reply
  6. Keith

    Former ASE Master Tech, I have a truck just like yours. I would start at the flex hoses at both front wheels and at the rear axle. These old hoses are prone to come apart on the inside and clog. Open each line (using caution) and try the brake pedal each time a line is opened. Then work your way back to the master cylinder until you are satisfied finding your stoppage, them replace parts as necessary. I would also suggest that if all of the original hydraulics ( master/wheel cylinders, hoses and even the hard lines be replaced as there is no way to inspect these parts from the inside) they may look good on the outside but you never can tell and if you are staying with a single pot master cylinder, any part that fails will leave you without brakes!

    Reply
  7. Joe Jendresky

    Great question and very informative. I planned on replacing the brakes on my mustang this winter. This could save me a lot of time.

    Reply
  8. Richard Cotton

    If in the process that was suggested by one of the other responders if no fluid comes out of the master cylinder it is possible that the residual pressure check valve was installed backwards.

    Reply
  9. Josh

    Replaced MC (forgot to bench bleed) and a couple of wheel cylinders on a 1964 F250 w/drum brakes. I used a vacuum pump to bleed brakes and the fluid looked pretty good. But there is little to no pressure being built up with the brake pedal. Is it the failure to bleed the brake MC or am I just impatient?

    Reply
    • Customer Service

      Hello Josh,

      Yes you may have air still trapped in the master, but it’s never too late to bleed it.
      simply remove the brake line attach the bench bleeding tubes to the master and bleed it by pedal.
      A method I like better although is to syringe bleed using a syringe tool. (Cardone 10-5000MCB Master Cylinder Bleeder Tool)
      It is fast an easy, just follow the direction to use and we’ll have a video out in the next couple weeks on how to do it too.

      Wrench Safe,
      Mark CCRC Video Membership

      We’d love to have you be a part of our community. We are convinced you will enjoy the benefits of becoming a member and having access to the best instructional how to videos and professional tips. We would like to offer you a special promotion for your first year membership.
      http://go.ClassicCarRestorationClub.com/C9938

      Reply
  10. tbroyan

    I have a 1941 International Harvester K2 pick up truck. My father-in-law learned how to drive in that very truck when he was about 10 years old. When I became the owner of it (only the fifth since new) I was giving it the once over just for grins and found when I was replacing the brake fluid that the right rear wheel cylinder wouldn’t bleed out. After going over the brake lines I found a nail in the brake line using the head to plug off what turned out to be a leaking wheel cylinder. I guess and old farmer trick to keep it going and still have some brakes at least. In any event even if the brakes seem to be fairly functional it’s not a bad idea to go over every inch, inside and out to make sure something “creative hasn’t been done in the past.

    Reply