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Stripped threads from the gear box mount ! what to do?

S3 Paul May 16, 2011

  1. S3 Paul

    S3 Paul Well-Known Member Regional Rep

    After replacing a blown Dm flywheel at the weekend... when rebuilding the car we noticed the thread of the rear bolt on the gear box mount ( the two bolts vertical under the air box ) Had seen better days... sure enough when being re torqued it gave up the ghost and stripped the thread in the mount.
    No biggy i thought, just ring audi to order a new one... Well i rang them today and... £200.80p plus vat !
    So after pulling my pants back up i thought... surely it could be helicoiled to the M12x1.5 thread it should be ( i could only find a kit with inserts that are 16mm long ) or helicoiled to the more common size of M12 x 1.75,
    The third and final option is make a threaded insert myself . Say M16 but tapped to M12x either 1.5 or 1.75 .

    Im undecided whats the best option but the Audi price is stupid given what it is.
  2. Jacko4130

    Jacko4130 Goodie Gum Drops

    Ebay for mount, used engine/gearbox mounts only go for £10/£20 if you can find 1
  3. S3 Paul

    S3 Paul Well-Known Member Regional Rep

    I had a look, But because its the alloy block that bolts to the gearbox... not normaly sold as the "mount "
  4. Prawn

    Prawn My other car is a MINI!!!!

    I stripped one of mine a while back Dave, and I'm fairly sure it was you that told me the correct thread size.

    £35 for a helicoil kit on ebay and it's perfect again. Only took 10 mins to do as well.

    Get it ordered.
  5. Andrew@A.L.D

    Andrew@A.L.D May add NOS to 600+bhp S3.

    I had the same problem and just retapped the mount
  6. S3 Paul

    S3 Paul Well-Known Member Regional Rep

    I looked on eBay for a repair kit.
    The inserts in the kits I found only measured 16mm long.
    I wasn't sure it was going to be deep enough
  7. ayfreetee

    ayfreetee Well-Known Member

    16 mm will be strong enough as the coil is steel, just make sure you use thread lock to make sure the coils stay in, be sure when you tap the hole out for the coil that you do two turns clockwise the one turn anti clockwise to clear the tap so that it doesn't bind and ruin the new thread and make sure you use oil while tapping, WD40 will be okay, I am an engineer and have fitted hundreds of heli coils in my time so I'm not steering you wrong.

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