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Thread: Be careful when cleaning and conditioning your soft top.

  1. #1

    Be careful when cleaning and conditioning your soft top.

    The other day I washed my soft top in the midday sun, which I thought I'd done before, but the result was a little surprising. The canvas of the top tightened up like a drum, and all the wrinkles came right out, but when I went to do a final polish of the screen I discovered that the canvas had contracted enough to literally tear the windscreen glass apart!

    I would suggest only condition and clean your soft top in the shade, or at the beginning and end of the day.
    Andrew Macpherson

    Expert Z8 Inspections, with full support for both Z8 sale and purchases.

  2. #2
    Z8 Addict Z8doc's Avatar
    Join Date
    Jan 2004

    Windshield cracks are a constant problem....

    I have had this happen 3 times. My BMW service center states that it can be caused by several factors that are warranty issues like the soft top being adjusted too tight (which you implied), from faulty glass, or from chips that lead to crack propagation with the expansion and contraction of the glass in response to heat or cold (like the midday california sun).

    My first crack appeared 4 months after buying the car, when I was washing it at a car wash on a cold day. The heated water caused to to expand and split. The second split occurred while at the dealer after they installed the new one. They were washing it, and it split. The third occurred 3 weeks after getting it back and once again, washing it on a cold day at a car wash (a different one too).

    The dealer said that the last crack was a result of 2 factors, one the heat differential and improper glass installation by their glass technician (who actually was a contracted vendor and not a Z8 mechanic). They THEN received a 6 page techinical manual from BMW AG on the proper installation of a windshield for a Z8. The car MUST sit for 48 hours after installation on a level surface I was told BEFORE you drive it. I have not had a problem since. The glass is only about 2.0 mm thick and any chip can be of concern and potentially propagate (not warranty).

    Every owner at the Z8 Driving Experience had had their windshield replaced at least once for similar reasons. Hope this info is helpful. Image included of my first crack - straight down the middle !

    P.S. I no longer have that hang tag on the mirror as I discoverd it covers the light sensor on the back of the mirror and makes the mirror darker than usual during the day and not dim or lighten to head lights after dark.

  3. #3
    Sport Button On - DSC Off
    Join Date
    Sep 2006
    drove my car to the office today and put the top up in the parking lot to keep debris from nearby trees out. Windows open about an inch on both sides. Sunny and mid-80s. Quite surprised to see my windshield cracked when I left work about 4 hours later.

    Is replacement best left to BMW or has anyone had good experience with auto glass specialists?

  4. #4
    It is six of one, half a dozen of the other - the best is to find a shop that has done some Z8 screens before, because they do need a bit of care on installation. Mine was replaced by Beverley Hills BMW, but I woulnd't say it was a perfect job as there is a lot of rubber like sealer all around the screen which still weeps out, especially on the passanger side.

    While doing the Mille Miglia event in Europe I noticed that nearly all the owners just leave the roof up, but not pulled down taught, to keep the sun out. However I'm not sure if this was done because of the screen cracking issue or not, but it is still a useful thought if the car is parked in the open in a secure area as ambient air temp, and the suface temp of something sitting in full summer sun are two different things.
    Andrew Macpherson

    Expert Z8 Inspections, with full support for both Z8 sale and purchases.

  5. #5
    Crazy! any car detailing should be done in the shade... I will keep this in mind the next time I let the car sit out in hot sun for a long time- usually its in a shaded or garaged area...