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Thread: Torques spec, transmission mount/saddle 1973

  1. #1

    Torques spec, transmission mount/saddle 1973

    guys,
    Does any one know the torque spec for the 2 bolts that go through the mounting block to attach the nose of the transmission to the car on a 73 911? It is the pointed bolt, part # 901.305.317.00, that uses a 19 mm socket. Neither Haynes nor the factory spec book seem to think that a specific number is important but I would prefer not to strip out the threads in the body. On the other hand, having the bolts drop out and cause the nose of the transmission to gouge out the pavement is probably not going to win me any friends at the Ohio Department of Roads and Dirt. Right now I am using 50 foot/pounds.

    Thanks

    caproader

    73.5 Targa
    73S with Sporto
    69 912

  2. #2
    Quote Originally Posted by caproader View Post
    Does any one know the torque spec for the 2 bolts that go through the mounting block to attach the nose of the transmission to the car on a 73 911?
    I think the factory neglected to list a torque for those two bolts.

    The torque listed for the M12 x 80 front suspension crossmember bolts, which also thread into the body, is 9.0 mkp (65 lb/ft).
    If the transmission bolts are longer than 80mm, you can reduce that torque spec a bit. If they're graded higher than 8.8, you can use that spec regardless of length.

    Jon B.
    Vista, CA

  3. #3
    Thanks Jon,

    The 72/73 parts catalog does not give a length for the bolt, but checking a spare bolt in my parts collection shows 55 mm with 8.8 on the head. I think that I will go with 65 foot pounds.

    Thanks again,

    John

  4. #4
    Quote Originally Posted by caproader View Post
    On the other hand, having the bolts drop out...
    If you're concerned about the bolts coming loose, then dab some bright paint on the sides of the heads, and check them from time to time to see if the marks have moved.
    I wouldn't exceed 65 lbs/ft of torque on those bolts, and risk damaging the threaded receivers in the chassis.

    Jon B.
    Vista, CA

  5. #5
    Jon,

    Too late on the thought about stripping the threads in the chassis. The reason for this thread is that I had to install a time cert in one of the (stripped) threaded holes. Now that I got it all back together, I wanted to make sure that I did not over stress things.

    Thanks again.

    John

  6. #6
    Senior Member
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    Aug 2011
    Location
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    I found a spec in the '84 Bentley of 80 Nm, 58 ft/lb for the trans mount to body bolt.
    25 Nm, 18 ft/lb crossmember to transmission nut.
    E Sully
    1973.5 911T

  7. #7
    From the 70s Turbo Carrera Workshop Manual, page 10-6...
    Engine and transmission carrier hex head screws: 9.0 mkg (65 ftlb)

    DSCN0852.jpg

    Same page, bottom of the other side, dated 1978.

    DSCN0853.jpg

    Jon B.
    Vista, CA

  8. #8
    Thanks to all for your help.

    John

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