Which socket

Discussion in 'Airheads' started by picinisco, Sep 26, 2013.

  1. picinisco

    picinisco Scottish Transplant

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    I am at a point where I am attempting to remove the bolts holding the con rod to the crank on my R75/5 engine. It would appear that the bolt heads take a torx T54 socket but want to verify this before I try it. Can any one shed any light on this. Is it torx or is it some Teutonic secret tool.

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    #1
  2. rambozo

    rambozo Been here awhile

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    Not sure about a /5, but /7 and upwards all have a spline bolt

    I wouldn't use that torx until someone comes along to verify, I'd imagine
    /5's use a spline as well
    #2
  3. Airhead Wrangler

    Airhead Wrangler Adios Mexico

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    it's a triple-square head, also known as an XZN head. Pretty common on german cars. It's most definitely NOT a torx head.

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    #3
  4. disston

    disston ShadeTreeExpert

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    [​IMG]

    "Triple square bit applications are for European vehicles and double hex bit applications are for Asian vehicles. A triple square bit will strip the head bolt of an Asian vehicle." quoted from a Snap On page.

    Triple square or XZN or spline drive tool bits are available in several places. The Snap On brand is probably over rated but it won't break like some cheap ones will.


    Just like Torx and Hex drive bits that come with a hole in the center and called "Security" bits the XZN bits can be found with a hole in the center. Probably not a good choice for our application. The rod bolts are one time use items and they are tight. Cheaper tools will break
    #4
  5. Biebs

    Biebs BMW Airhead

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    crazydrummerdude posted in his My 1974 R90/6 never-ending project, with plenty of pics. about his bad experience with the connecting rod bolt tool that he bought from AutoZone but I don't think that he ever followed up with what worked for him. I need to get the connecting rods off the RS so I started looking around for info. Here is what I found:
    This is known as a 12mm triple square internal wrench bit.


    I bought the CarQuest STL60780 tonight for $6+ and will be using it tomorrow morning.


    Link to thread:

    http://www.bmwmoa.org/forum/showthread.php?32759-Connecting-rod-bolt-tool
    #5
  6. PaulRS

    PaulRS Dutch fool

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    Mine is from Stahlwille.

    Stahlwille M10 2054.

    Paul.
    #6
  7. Plaka

    Plaka Brevis illi vita est

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    I got a cheap PowerBuilt set forever ago from Auto Zone or someplace.. I've only ever used the one. It's lasted through a dozen rebuilds with out appreciable wear. You turn them with a 1/2" socket on a 3/8" drive. I finally hot glued the 10 into a cheapo socket for convenience.

    These bolts are at a specified torque and stay well oiled. So the dissassembly torque isn't great---not like things that get corroded. Make sure it is well engaged and you won't need a really high quality tool.

    Don't use your torque wrench as a breaker bar. Use a breaker bar.

    I finally found a use for all the old conrod bolts I've been saving. They are the same thread as brake lines. Make good sanitary plugs for when you have a line disconnected.
    #7
  8. bmwhacker

    bmwhacker Still on 3 wheels

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    Eons ago I was an Opel GT fanatic. I found that Opel used numerous similar fasteners in their engines. Years later when I ran into the connecting rod bolts on a BMW engine, they looked strangely familiar. Dug up the old Opel tools and they were a perfect fit.:clap


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    #8
  9. disston

    disston ShadeTreeExpert

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    Back in the '70's sometime a stranger wanted me to help him with his Opel. Needed brushes in the generator. It was the last time I saw a generator instead of an alternator on a car.
    #9
  10. Plaka

    Plaka Brevis illi vita est

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    VW kept it up for a long time. Alternator conversions were popular and the generators ended up on home cooked wind and water plants. I had am MG with a centrifugal starter 20 years after everybody else abandoned them. Ya got the tooling I guess...

    I still have whitworth wrenches mixed in with things.
    #10