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Technical Brake Bleeding!?

Discussion in 'The Hokey Ass Message Board' started by jaw22w, Jan 2, 2022.

  1. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,464

    jaw22w
    Member
    from Indiana

    Actually there is a bushing there that the pin slides on. The bushings all move nicely and they are greased up along with the pins with white lithium and working correctly.
     
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  2. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,464

    jaw22w
    Member
    from Indiana

    In a PM it was suggested that I check for "knock off". In other words, the piston and pad pulling back from the rotor. I took a .003" feeler gauge around the car and could not get it in anywhere between the pads and rotors. It doesn't appear as though there is any pullback of the pads. That tells me that the calipers are not low drag style and that the RPVs are probably doing their jobs. That just leaves the PV. That is where my next attack will focus.
     
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  3. 61Cruiser
    Joined: Dec 5, 2013
    Posts: 146

    61Cruiser
    Member

    I’ve read through this entire thread as I’m always interested to read about other guys problems and then the solutions in case I ever find myself in the same position. Although I can offer no advise( there are so many better brains on this site than mine) I wish you well and will follow along.
     
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  4. VI Lonewolf
    Joined: Sep 2, 2017
    Posts: 17

    VI Lonewolf

    Do the pads pull back or just the pistons on low drag calipers. With the corvette master did you bleed front and back at the same time? I have dual Wilwood masters and I have to bleed front and back at the same time.
     
  5. perry parsons
    Joined: Jan 1, 2018
    Posts: 13

    perry parsons
    Member

    I believe the Master cylinder is the culprit . I am thinking that the Master is bypassing . even if you have a rock hard pedal on second pump but eventually pedal falls to floor ,in my opinion its the master.
     
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  6. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,464

    jaw22w
    Member
    from Indiana

    Two different MCs, displaying the same symptoms? The pedal does not fall to the floor. My pressure gauges say 1000 psi front and 900 rear and hold when I push the pedal down hard with either master cylinder .
     
    Last edited: Jan 10, 2022
    Just Gary and Boneyard51 like this.
  7. Just starting on mine replaced the master cylinder and didn't change anything.
     
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  8. bschwoeble
    Joined: Oct 20, 2008
    Posts: 775

    bschwoeble
    Member

    I'm going to ask a dumb question. Are you using a Ford type brake switch, and is it pointing up. When pointed up, it can trap air. If none of this applies, please disregard.
     
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  9. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,464

    jaw22w
    Member
    from Indiana

    GOT IT! Don't know exactly what fixed it but I have the best brakes I have ever had in this car.
    I tore all the brake lines out of the car and replumbed everything. I re-routed them slightly differently. I turned the PV right side up. I replaced the RPV in the rear with a new one. I did not think that the front RPV was holding the 2#, so I replaced it also. I highly suspect that the front RPV was the problem all along. Bled it out and HOLY SHIT! Test drive proves it out!
    I don't know what fixed it, but I really don't care at this point.
    Thanks for all you guys help and interest.
     
  10. Boneyard51
    Joined: Dec 10, 2017
    Posts: 5,580

    Boneyard51
    Member

    Wow! That is a let down! I wanted the smoking gun! But glad you got it fixed!








    Bones
     
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  11. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,464

    jaw22w
    Member
    from Indiana

    Yeah! It is kind of a letdown. I know the golden rule of one change at a time, but I just decided that after 7 years of fighting basically the same problem, it was time to just start over. All new stuff.
    My 1926 Ford Model T is my DD. Sunshine, rain or snow. I have a couple other hot rods, but this is my favorite. I know a lot of you guys have seen it, but here it is again. 1926 T NEW Wheels.JPG
    It has better brakes now than when this pic was taken!!!!!
    Thanks again guys. This thread kept me motivated.
     
  12. Happydaze
    Joined: Aug 21, 2009
    Posts: 1,279

    Happydaze
    ALLIANCE MEMBER

    Congratulations! Now that its fixed I think the decent thing to do is to out all the old stuff back and recreate the problem and then solve it. We know the answer but not the method. We all need to know for when this crops up again.

    Enjoy the car !

    Chris
     
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  13. connielu
    Joined: Apr 21, 2019
    Posts: 167

    connielu
    Member
    1. A-D Truckers

    Glad you found it, been following along. Love the tall T BTW.
     
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  14. Doublepumper
    Joined: Jun 26, 2016
    Posts: 1,141

    Doublepumper
    Member
    from WA-OR, USA

    Good news! Glad you got it working. Curious to know if that residual valve is defective. My curiosity would have me testing it to see. Now go drive that beautiful Hotrod:cool:
     
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  15. SASROD
    Joined: Feb 7, 2007
    Posts: 135

    SASROD
    Member

    Did you end up with the 1" or 7/8" master cylinder?
     
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  16. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,464

    jaw22w
    Member
    from Indiana

    HA! I'll start on that tomorrow. I promise. :rolleyes:
     
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  17. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,464

    jaw22w
    Member
    from Indiana

    I have the Corvette 1" in it now. but I think I will change it back to the 7/8" for the reduced effort. I'm a glutton for punishment. I hope the problem does not rear its ugly head again.
     
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  18. Boneyard51
    Joined: Dec 10, 2017
    Posts: 5,580

    Boneyard51
    Member

    I’m voting you had a high spot in your plumbing and never got sufficient “ speed “ on the brake fluid to push the air out, since you said you rerouted some lines.






    Bones
     
    Last edited: Jan 12, 2022
  19. joel
    Joined: Oct 10, 2009
    Posts: 2,122

    joel
    ALLIANCE MEMBER

    Congratulations! I've been lurking and hoping for a definite cause; there is a lot of info here and worth the trip.
     
  20. Motorwrxs
    Joined: Aug 15, 2021
    Posts: 173

    Motorwrxs
    ALLIANCE MEMBER

    This is the one thread I look for every day here recently…totally stoked you got her fixed!
     
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  21. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,464

    jaw22w
    Member
    from Indiana

    Being the kind of guy who just can't leave things alone, after a pretty good test drive, I decided there was still a little tiny bit of air in there. I put the car on the lift, raised it up just like I always had done, nose down, just like it sits and took off the wheels to bleed again. Bled all 4. Shut the bleeders, filled the reservoirs and hit the pedal. CRAP! I lost everything. Back to the long soft pedal. Well hell, what did I do different?? Then I realized that I had the car nose up just a little bit when they bled out right. After the test drive, trying to improve it, I had bled it out a little nose down and got the long pedal. So I raised the nose a lot and bled again and the high hard pedal came back even better.
    I think Pist-n-Broke was the first to mention tilting the car very early in this thread along with several others. I had always heard of tilting the car but had never found it necessary.
    .
    I can guarantee tilting the car can be a thing when bleeding brakes.
    The moral of this story is... never too old to learn and quit being so hard headed and listen to people... sometimes.
    Anyway, I have great brakes now. Thanks again.
    Oh! And Boneyard51! There is your smoking gun.
     
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  22. Gets back to remembering Air will always rise when in fluid. Sometimes getting it around the corners so it can is the devil.
     
  23. chevyfordman
    Joined: Oct 4, 2008
    Posts: 1,151

    chevyfordman
    Member

    That is a great ending.
     
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  24. saltflats
    Joined: Aug 14, 2007
    Posts: 11,252

    saltflats
    Member
    from Missouri

    I like a happy ending. :oops: :D
     
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  25. jetnow1
    Joined: Jan 30, 2008
    Posts: 1,969

    jetnow1
    ALLIANCE MEMBER
    from CT
    1. A-D Truckers

    Thank you for telling us the ending, so often we are left hanging. Nice car!
     
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  26. Happydaze
    Joined: Aug 21, 2009
    Posts: 1,279

    Happydaze
    ALLIANCE MEMBER

    Good save!

    I'm curious to know the inclination of the master cylinder when the car is pitched as it was when the problem bleeding occurred, and also, for giggles, when the car is sitting normally on its wheels.

    Chris
     
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  27. Truck64
    Joined: Oct 18, 2015
    Posts: 5,316

    Truck64
    Member
    from Ioway

    I've found so called "gravity bleeding" useful sometimes, and for whatever reason sometimes the flow it just stops. Rapping on the lines along the length with a wrench or a screwdriver handle will get things moving again. I think somebody here mentioned that.

    The more sofa-sticated the brake system the more trouble it can be to get a good bleed it seems. Funny thing about brakes as important as they are, it seems to be one of those tasks always given to the "new guy". Let him deal with it.

    When I was in the .mil the official tool for bleeding aircraft brakes was a $35,000 pressurized hydraulic cart (I know it cost that much, because one of them had turned up "missing" against the commander's hand receipt for a while. He was Not Amused).

    But nobody hardly ever used those, at every unit I was ever at, and that was a lot, somebody in the toolroom always had bolted an old simple hydraulic hand pump to a plywood board and fitted braided hose to that. LOL. Your tax dollars at work.
     
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  28. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,464

    jaw22w
    Member
    from Indiana

    It's funny. I took the Model T out for coffee this morning. I am so used to having to double pump the brakes that even though the brake system is working correctly now, I am still double pumping the pedal. It's just automatic!
    Old habits are hard to break.
     
  29. SASROD
    Joined: Feb 7, 2007
    Posts: 135

    SASROD
    Member

    No pun intended?
     
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  30. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,464

    jaw22w
    Member
    from Indiana

    Ha! Old habits are hard to brake! Didn't even think about that.
     
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