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Starting on a '55 Plymouth Plaza Suburban

Discussion in 'Other classic cars' started by 71Charger_fan, Nov 26, 2016.

  1. hemirunner426

    Level 2 Supporter

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    Just playing devils advocate.

    When you bench bled the master cylinder you kept the end of the lines submerged in fluid at all times.When you installed the master cylinder you kept fluid in the reservoir.At no time was it subjected to the admosphere.

    You must be pissed.Not trying to be an a$$hole.I just can't think of anything else.
     
  2. 68RT

    68RT Well-Known Member

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    Remember, brake lines were replaced and sometimes they must be pressure bled. Had a Nissan hard body and had to tip it about 30 degrees to the side and bleed the line where it split on the right firewall. No other method worked without a fast pressure bleeder.
     
  3. 71Charger_fan

    71Charger_fan Active Member

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    "When you bench bled the master cylinder you kept the end of the lines submerged in fluid at all times.When you installed the master cylinder you kept fluid in the reservoir.At no time was it subjected to the atmosphere."

    I was very careful with the bench bleeding.

    While bleeding it this time, I tried tipping the car front to back. Before buying and installing a third MC, I guess I'll try tipping it as far as I can get it side to side and bleed it again.
     
  4. 68RT

    68RT Well-Known Member

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    Look for humps in the lines that would catch air. When you use the normal bleeding methods, you only move a very small amount through a line and if it doesn't get the bubble past the hump it just returns to the hump before the next stroke.
     
  5. 71Charger_fan

    71Charger_fan Active Member

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    I keep looking at the hump in the line where it follows the curve of the differential housing thinking "you're in there, aren't you."
     
  6. Bearhawke

    Bearhawke Things happen for a reason

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    What bugs me about the whole mushy brake pedal thing is when the rear hose is clamped off as per @71Charger_fan , said pedal becomes firm.
     
  7. geraldg

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    Could he clamp each rear wheel one at a time and see what happens ?
     
  8. geraldg

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    Are you sure you have the right proportioning valve ?
     
  9. 68RT

    68RT Well-Known Member

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    Sign that the hump is the problem can you loosen and turn sideways temporarily?
     
  10. geraldg

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  11. 71Charger_fan

    71Charger_fan Active Member

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    Even if the proportioning valve was bad, it's a closed system. I'd think I'd still get a hard pedal.

    I've got a reverse bleeder coming. I'll try pushing fluid from the wheel cylinders. If that doesn't work, I'm paying someone to figure it out.

    Meanwhile, I've started fitting new interior panels.
    Plaza side panel.jpg Plaza side panel (2).jpg Plaza side panel (3).jpg
     
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  12. 71Charger_fan

    71Charger_fan Active Member

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    This arrived today. I'm going to start by clamping off the rear brake hose. Then, use my bottle jack to get one rear wheel higher than the other then push brake fluid from the low side to the high side. That should, once and for all, eliminate the question of whether there's air caught in the hump of the rear line. Following that, I'll push some fluid up and out the MC with the front end elevated. I really hope this gets it once and for all.
    phpSBq5ZmPM.jpg
     
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  13. petegee77

    petegee77 Member

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    I'm with you. It's beautiful just the way it is. Especially with the wood .
     
  14. 71Charger_fan

    71Charger_fan Active Member

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    I was on vacation, then, the temps were just too hot to deal with it. Today, I finally touched it again. I plugged the MC and gave the pedal a push. It was a good firm pedal as it should have been. But, when I pushed hard, I heard a funny noise and the pedal slowly slipped to the floor. I got out another MC, bench bled it, installed it, and plugged it. The pedal is hard as a rock and doesn't sink at all. So, I hooked up the fronts and it's still good. Tomorrow, if it's not too hot, I'll cross my fingers and hook the rears back up.
    Plaza MC plugged.jpg
     
  15. Bearhawke

    Bearhawke Things happen for a reason

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    WOW!

    That is weird, the part of having your brake pedal starting dropping when you heard that funny noise. Although I've heard horror stories about repop products i.e. your master cylinder that aren't the best, shall we say.
     
  16. 68RT

    68RT Well-Known Member

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    That weird noise probably was made by fluid coming back around the piston cup. Definitely a no no.
     
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  17. 71Charger_fan

    71Charger_fan Active Member

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    Finally buttoned it up and gave it a brief road test today. The original drum brakes are sensitive to adjustment. I left them dragging very slightly and decided to let them wear in through short drives around the neighborhood. I tried the reverse bleeder on the passenger side with the rubber hose clamped off and the drum off. It pressurized the rear axle line and moved the pistons out on the wheel cylinder as it should have. After three or four times of letting the wheel cylinder pistons extend and retract, an air bubble made its way out. So, looks like I had a combination of a bad MC and a stubborn air bubble.
    phpTVkyq0PM.jpg
     
  18. dana44

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    Yeaaaaa! So glad that was finally figured out, it was hounding you for literally months, and you weren't doing anything wrong (I always hate that the most). She definitely looks nice out in the sun, enjoy the summer cruises.
     
  19. 71Charger_fan

    71Charger_fan Active Member

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    I'd like to find the trim for the leading edge of the hood in chrome.
     

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