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Tires and Brakes

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  • #46
    Originally posted by simplyconnected View Post
    No, in honesty, the factory evacuates the system, checks for leaks, then if ok it fills the brake system (all in one hook-up that takes 30 seconds).

    I don't know how deep your vacuum goes. If it is anywhere near the factory's you won't need anyone's foot. They fill with the system closed-up.
    On race cars we typically bench bleed, do the "normal" pump up and bleed each wheel until clear then we do a vacuum bleed to suck the last few bubbles out of the master.

    If the pedal isn't rock hard, do it again.


    • #47
      Bill, an assembly plant is amazing to watch. They produce a car per minute (436 per 8-hr shift), so all operations must be FAST.

      They have tank farms (with every liquid in huge silos) away from the plant, and a central vacuum system, with huge evacuation pumps (compressors) and accumulators. The line never stops, so all the equipment is duplicated for immediate changeover in case of failure.

      Evacuate means just that. Air has no choice but to come out, and liquid has no choice but to fill perfectly, every time, without wasting a drop.

      'Brakes' are only one system. At the same time the brakes are evacuated and filled, so is the air conditioning system the cooling system, windshield washer bottle, and gasoline. They're done in different stations, but in the same Final Area.

      Filled brake and cooling systems NEVER have a void or 'bubble' because again, it is evacuated, then immediately filled (in sequence). Then, the line worker removes the fill hoses and installs the caps.

      What about the thermostat and heater core shutoff? Evacuate means ALL air is removed simultaneously from the system, so those components never stop the vac. By the way, that's why the radiator hoses have that wire inside, so they don't tear under vacuum.

      All the OEM's have done it this same way for over fifty years. If a evac/fill machine goes down or a car's brake system has a leak, the repair area has duplicate machines. That's three brake evacuate & fill machines, three A/C, etc., in each assembly plant. Equipment cost is peanuts compared to line down time.

      How about tires? The tire room loads the correct five wheels, machines index and insert stems in each, mounts correct (directional) tires, inflates, and balances, FIVE per minute, every working minute. Tire semi's are dropping loads many times, all day-shift and afternoon-shift. 2,180 per 8-hr day shift, and another 2,180 for the afternoon shift.

      M/C's always come 'dry' and are never bench bled at the plant. Every new car must be delivered with a perfect brake system.
      My latest project:
      CLICK HERE to see my custom hydraulic roller 390 FE build.

      "We've got to pause and ask ourselves: How much clean air do we need?"
      --Lee Iacocca