Sagging front when car is off

Lincoln Mark VII

  1. Darth_Elvis

    Darth_Elvis LVC Member

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    When I turn the car off the front bags will deflate & I have to sit & wait for them to refill for about 5 minutes or so. Solenoids replaced but did nothing. The mechanic said it MAY have a leak but I replaced the original about 5 years ago. The car in the morning will sag in the like a hot rod ALMOST all the time. Sometimes when I turn left into a lot the bags deflate, sensor maybe? Thoughts?
     
  2. Elessee

    Elessee Well-Known LVC Member

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    I went all through this problem. Replaced just about everything before discovering the trouble. In the end, my leaks were near the bottom of the right front bag.

    Notice the sharp bend at the bottom, where a bag curves. It constantly flexes there. Mine had hundreds of ozone cracks, mostly on that lower, curved area. Difficult to see. Wash it and use illumination. A very few cracks penetrated all the way through. Most were just shallow surface cracks.
    Now, when a bag is completely inflated, like when driving, this rubber area is flattened out, not curved. The bag is taller , not short. The crack is closed and won't leak much if at all. A slight leak would be refilled by the pump, but you cannot hear it.
    (Picture yourself holding a piece of thick rubber with a crack. When you bend it, the crack opens. But it closes when flat.)

    [Edit.. my memory is returning. You can test it with soapy water. I used children's bubble stuff but anything that foams will do. But be aware the cracks don't always leak. ALSO BE aware this is a freaking dangerous situation. DO NOT stick a leg or even an arm under the car while the system is inflated. It can deflate flat on the ground in half a second, and crush a mouse. Not kidding. Use jack stands. ]

    I sometimes got a very fast deflation, perhaps by parking on a hill or with a wheel up on a curb. The frame / suspension is uneven. The car tries to remain level. One of the bags might be compressed more, and therefore it is shorter. And a crack opens wide, releasing lots of air.
    Parked overnight it almost always sagged down in the front.
    Mine held air most of the time. I could drive on it. But sometimes the bag leaked so bad I had to stop many times to let the pump work (I cooled the hot pump with water). Eventually made it over the mountains, and home...
     
    Last edited: Aug 17, 2017
  3. Elessee

    Elessee Well-Known LVC Member

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    I found good replacement bags at a boneyard. $10 for two? A lot of cars used these same ones (I have an '88 Mk7).
    Pick good looking ones. I examined them carefully. They come off really easy. Need a heavy screwdriver and a hammer. That's it. Look inside... nice and clean. No cracks outside or inside...
    Sunshine and electrical equipment causes ozone cracks. Sunshine is (mostly) blocked by the fenders, but electrical stuff in a garage can poison the air.
     

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