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  1. #1
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
    Join Date
    14 Aug 2010
    Medford, MA
    '90 900 LPT with a flat-nose conversion

    Disassemble and repair flat-front bumpers - c900 '79-'86

    I was looking around the internet for any (ANY) information on how to repair the self-repairing bumpers on the flat-nose 900 cars. I found nothing! I did figure it out, but I thought I'd post pictures and instructions here.

    The reason these bumpers are called "self-repairing" is because they can come back into shape (slowly) after an impact dents them. They can do this because they consist of a three-part system: aluminum bumper beam in back, white honey-comb plastic (looks like an ice cube tray) inside, and black bumper cover wrapping everything. The black bumper cover and the aluminum beam provide support. The honey comb/ice cube tray plastic is the key. It can deform and then will slowly come back. But nowadays, with the newest of these bumpers just under 30 years old, the plastic is often no longer pliable. Modern bumpers contain foam instead of this self-repairing white plastic honey comb / ice cube tray. If yours has degraded and/or shattered, you can probably remove it and replace it with styrofoam insulation, cut to the proper shape and size.

    Sometimes you'll see a car with forlorn-looking bumpers - maybe they've hit something and are kinked, maybe they're rattly because the interior honey comb is broken. Or, most commonly, they're just missing the chrome strip due to age or wear. A lot of that can be fixed.

    If your bumper has a dent, it is possible to re-shape it with a heat gun and a lot of time. If you take your bumper off and it rattles when you move it around, a lot of the internal honeycomb/ice cube tray pieces are probably cracked. You can leave these out, or if you want something to push the bumper back into a more bumper-like shape (if the bumper cover has a dent), you can probably replace with some white or pink styrofoam insulation from your local home-improvement warehouse.

    Some people believe that the best way to repair the chrome strip is to buy some new, self-adhesive stuff, stick it on, and be done with it. But the original chrome strip attachment was far more sophisticated than just a bit of adhesive. You know how they call the bumpers "self-repairing." The geniuses at SAAB actually made the chrome strip spring-loaded, so if you accidentally plow into something, the bumper can deform along with the chrome strip, and then everything can pop back into place. So don't be tempted to just stick a bit of adhesive trim on your bumper and call it a day. It'll just fall off in time. Instead, do it the right way and preserve your car the way SAAB intended.

    Difficulty: 1.5/5

    Tools Required:
    -8mm allen wrench or allen socket (socket is better)
    -13mm wrench
    -Really big phillips (#3 pozidriv) screwdriver, like for ski bindings. This is critical. You need to not strip the screw heads.
    -Wire cutters (if you're going to replace the chrome strip)
    -Drill with 1/4" and 1/16" bits (if you're going to replace the chrome strip)

    Parts Required:
    -Chrome strip (you can use the rear one from a later car and just cut it to length)
    -Possibly a 1 1/2" long tension spring from the hardware store if yours are missing (see pictures to get an idea of what to look for)

    First, take the bumper off the car. This is easy. Look for the two large 8mm allen bolts going vertically, from bottom to top (bolt heads on bottom). Unscrew them and remove them. You can then pull the bumper off frontwards. Nice!

    Then it's time for disassembly. Remove the 13mm nuts that hold the aluminum bumper fittings onto the bumper beam.
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    Then remove all the phillips (pozidriv) screws. There should be 23 of them, I think. The screws are M5.5 x 12mm pan head self-tapping screws. I believe their closest equivalent is a #12 x 3/4" american size sheet metal screw. Be careful not to strip the heads of the screws. You will have to exert significant downforce on the screwdriver to keep it engaged with the screws, but it can be done. Vise grips don't really grab hold of these screws. They just slip off, so you have to get them with the screwdriver. They are steel screws into aluminum, so there will be corrosion holding them, but they're self-tapping sheet metal screws, so it isn't SO bad.

    You can upgrade these to stainless for a few bucks before reassembly if you like. There are M5.5 x 12 stainless screws on Ebay for only a few dollars.
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    Then, remove the aluminum sheet panels on the back of the bumper. These sheet panels hold the bumper cover onto the bumper beam. They should come right off.
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    Then, you can see the springs holding the trim. The springs will be at either end of the bumper, and go through a hole in the plastic internal honeycomb pieces. The springs must be detached from the bumper cover to remove the chrome trim and internal pieces.
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    Remove the aluminum beam from the back of the bumper cover. Some of the internal white honeycomb/ice cube tray white plastic pieces should come out with the beam. Set the beam aside, and carefully remove the rest of the white honeycomb/ice cube tray pieces. Yours may be brittle and shattered from accidents. If this is the case, remove the shards and discard them. Then slide the two white pieces on the ends out toward the center of the bumper and remove them.
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    NOW you have the thing all apart. Replace any broken honeycomb/ice cube tray white pieces if you want to. Or just leave them out if they're very damaged and you can't find suitable replacements. You could probably use styrofoam insulation foam if you really wanted something in there. I find the bumper holds its shape without all of the white pieces inside present.

    To attach the trim, first drill a 1/4" hole in the chrome trim on one end. Then make it into a keyhole as shown in the picture.
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    Slide the trim under the attachment clip in the center of the bumper. With a properly-made keyhole, it should snap securely into place.
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    Then, feed the end of the trim in the little slit on the end of the bumper. Grab the trim from the inside, pull it tight, and make a mark so about 3/4" (2cm?) of trim is showing from the inside. Thread it back out and drill a 1/16" hole in the trim. Feed it back in, hook the spring on the trim, and put in the white piece with the hole in it on the end. Pull the spring through the hole and "hang" the hook end of the spring on the bumper cover where it went before.
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    Put the rest of the white ice cube tray/honeycomb pieces (or whatever styrofoam you prefer, if you can't find a suitable replacement) in the bumper cover and carefully insert the bumper beam, and bolt everything back together. I started with the edge pieces and worked my way inward to the center. I think this is the way to do it to get everything best aligned.
    Last edited by euromobile900; 22 December 2015 at 13:57.
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