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Hot Rods 39 Ford brakes will not bleed

Discussion in 'The Hokey Ass Message Board' started by Jalopy Kid, Dec 2, 2016.

  1. The car is a 37 Ford, but has 39 brakes on it. They were working great, but the wheel cylinders were leaking.
    So I replaced all 4 wheel cylinders. And now it won't build pressure.
    My first thought was maybe the master cylinder crapped out when the pedal bottomed out during bleeding. So I put a new one, but it didn't change anything.
    If it sits for a few minutes, it will build resistance while pumping (still goes to the floor) and you can hear the wheel cylinders moving. Crack a bleeder, no air, just straight fluid with normal pressure. Close the bleeder and pump again, no more resistance. Pump and pump, still no resistance. Open the bleeder and the fluid trickles out. Close the bleeder, pump again, open the bleeder, and nothing comes out. Like it has no pressure.
    I've double checked the push rod, it's getting full stroke. I've tried lengthening the pushrod, shortening the pushrod, no change. I've pulled the master off and bench bled it. No bubbles. I've pulled the hubs off, and all the wheel cylinders are dry, and do move. I've adjusted the brakes.
    The owner of the car and I spent nearly 8 hours trying to bleed them. We've gone through 2 quarts of fluid. I've tried vacuum bleeding. The only thing we didn't replace was the hoses, as they look good, no cracks or anything. The car was actively driven with working brakes up until yesterday.
    I'm not getting any air out of the bleeders. It's always straight fluid. Just won't build pressure.
    Any ideas?!?!

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  2. Slopok
    Joined: Jan 30, 2012
    Posts: 2,565


    The hoses can look fine on the outside but be swelled shut on the inside. But you said they were working prior to this so I don't know.
    stillrunners likes this.
  3. 41woodie
    Joined: Mar 3, 2004
    Posts: 1,065


    What Slopok said x 2, when putting the woodie back on the road I wrestled with bleeding the brakes for two days before I removed one of the brake hoses and found it collapsed on the inside. From the outside it looked fine.
  4. Slopok
    Joined: Jan 30, 2012
    Posts: 2,565


    On second thought you wouldn't have used 2 quarts of fluid if the hoses were blocked.:confused:

  5. Mac VP
    Joined: May 13, 2014
    Posts: 321

    Mac VP

    Check the pistons in each wheel cylinder to make sure one or more has not been pushed inward during handling/assembly. This could cause the piston to not be fully positioned in its bore.
  6. I'm pretty sure I have an extra set of hoses.
    I'll double check the pistons in the wheel cylinders, and if they look ok, I'll swap the hoses out with new ones.
    You'd think though it swell the hose or something ?

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  7. I let the car sit overnight with the bleeders open.
    No change.
    I undid the brake lines, and put plugs in the master, to see if it's working.
    Pedal was rock hard.
    Undid the rear plug, and screwed the line for the rear brakes in.
    Pedal still rock hard.
    So I know the rear brakes are good and working.
    Unscrewed the front plug, and screwed the front lines in.
    No pedal.
    Changed the front hoses. Still no pedal.
    I dropped the front jack stands and let the front axle hang, so it's for sure lower than the master cylinder.
    Still no pedal.

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  8. Can you post some pictures of the cylinders. When you say no pedal is it just going straight to the floor with no pressure? Is there any inline proportioning valves??? Or pressure holders as I like to call them. Are the bleeder seats correct with the right bleeders. And you say there is no leaks anywhere but you went through 2 quarts of fluid? Did you hit the metal lines with a air hose and blow them out? Unhook the front line from master cylinder and hit it with air see if you can hear or see a line crack. I love brakes
  9. And they are NoT upside down right???
  10. Standard 39-48 Ford master cylinder.


    Drivers front wheel cylinder.



    Passenger front wheel cylinder


    Pedal goes right to the floor.


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  11. canning
    Joined: Jan 22, 2012
    Posts: 70


    Mechanical breakage of clevis or pedal fulcrum?Something cracked or split in linkage that flexes when pedal is depressed, but returns to normal position.
  12. I've unhooked the drivers front brake hose, plugged the line, and I have a solid pedal now.
    So I've narrowed down to the drivers front wheel cylinder.
    I'll take the hub apart and see what's up.


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  13. Fordors
    Joined: Sep 22, 2016
    Posts: 2,895


    There have been a number of threads on about reproduction wheel cylinders with holes drilled in the wrong area causing problems like yours. I'd take an old and new one apart and compare them.
  14. 3 wheel cylinders are Raybestos. One is Macs auto parts. Guess which one doesn't work!
    I can't get another wheel cylinder until Monday. So I'll change it out then, and report back.

    The macs one appears to be "working". It moves the shoes. It's not leaking. But doesn't seem to hold pressure.

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  15. Kid: I did a thread on this a couple of years ago. I had wheel cylinders (new ones) that I had a lot of trouble with them leaking. Finally, I got beyond that but had the same problem you have. Three things to consider: The holes drilled incorrectly as stated above, the pistons being shoved too deep in the cylinders (according to the instruction sheet) which I never understood, plus, by the time you install the return spring from one shoe to the other, you have shoved the piston in as far as it will go anyway since them springs are STIFF, last, and the thing that cured all my issues. If you look inside the cylinders, you likely won't find the little medal dishes that back up the rubber cups. I discovered this through a conversation with a friend. I managed to find some at an old parts store. Installed them, bled the brakes and that was the spring of '14. Not a problem since then. I hope this helps you. Tim
  16. BJR
    Joined: Mar 11, 2005
    Posts: 6,448


    If it doesn't hold pressure, it must be leaking fluid, right?
  17. kbgreen
    Joined: Jan 12, 2014
    Posts: 337


    I've had this problem and it may not be your equipment. Did you bleed the master cylinder before connecting the brake lines? Your MC should have come with a bleeder hose about 6-inches long and a plastic fitting that will connect to the rear of the MC. I've tried to ignore this step but when I do, I get the results you are reporting.
  18. He says it never built pressure, so there's no pressure to loose. The release or lack of "hold"ing built up pressure should show a leak someplace
  19. alchemy
    Joined: Sep 27, 2002
    Posts: 15,775


    I had some Macs cylinders with the offset holes, and found if I adjusted the shoes out so they fit tight to the drums BEFORE I added the fluid and bled the brakes allowed the weird hole to not bleed past the cup. But, I did have leaking fluid past the cylinder's outer rubbers to indicate the problem for me. If you aren't loosing any fluid, I doubt you have this same problem.
    timwhit likes this.
  20. Replaced the Macs wheel cylinder with a Raybestos. Problem solved.


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    Hitchhiker and K13 like this.

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