'70 Z-28 Manual Steering

Discussion in 'Original Drivetrain Topic' started by Mulsanne Blue, Jul 10, 2013.

  1. Mulsanne Blue

    Mulsanne Blue Veteran Member

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    My '70 Z originally had manual steering and I'm trying to gather parts. The only part, according to the parts book, that I'm not sure about or have ever seen come up for sale is the pitman arm. If I'm reading the books right, the number should be 6.859 3964877, http://www.gmpartswiki.com/getpage?pageid=86765. Can someone check the cast number on their original set up to confirm?

    As for the box, what should the turning ratio be? I found a dated 5679142 box, but I'm not sure if the ratio is correct.

    Appreciate the help. Scott
     
  2. Gary S

    Gary S Administrator Lifetime Gold Member

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    The Z28 manual steering box had different gears inside it than the other Camaro boxes. Z28 box was 4.1 turns lock to lock. Non-Z28 manual box had 6.2 turns. The casting numbers on the box don't identify the gears inside.
    As a comparison, the power steering box was 2.3 turns lock to lock, so you can see that any of the manual steering boxes are slugs compared to power steering boxes.
     
  3. FlaJunkie

    FlaJunkie Veteran Member Lifetime Gold Member

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    From my rebuild. Pics are worth...

    [​IMG]


    [​IMG]


    [​IMG]

    My arm is a part listed for a power steering car. I have never changed it; I need to investigate this further.

    Does anyone have a pic of the 3964877?
     
    Last edited: Jul 10, 2013
  4. DCL70

    DCL70 Veteran Member

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    I have one in my collection that is just like the one in FlaJunkie's photos.

    Casting #'s:
    Saginaw logo
    "13"
    "5679142"
    "113" (113th day of 1970)

    "B1320" stamped on pad (132nd day of 1970)

    Cover:
    "7802287"
    "CBC"
    "T"

    Pitman arm:
    "3864881A" and "GMT3"

    Dave
     
    Last edited: Jul 10, 2013
  5. FlaJunkie

    FlaJunkie Veteran Member Lifetime Gold Member

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    Dave, do you know what yours was used on? That pitman arm seems to be one for the power steering box.
     
  6. Gary S

    Gary S Administrator Lifetime Gold Member

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    The original arm on my 70SS with power steering is 3964881. It appears to be just slightly under 7" in length.(I can't get an accurate measurement with it installed).
    I don't know how long the manual steering arm should be.
     
  7. frankz

    frankz Veteran Member

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    The quick ratio manual uses the longer pitman arm.(7")
     
  8. DCL70

    DCL70 Veteran Member

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    I bought the steering box at a swap meet. You are correct, the 3964881 Pitman arm is listed for P/S.

    My 1970 Chev. Parts Catalog (Oct. 1970) lists the following Pitman arms in Gr. 6.859:

    3964881 - 70 Camaro w/P/S
    3964877 - 70 Camaro exc. P/S

    My 1972 Chev. Parts Catalog (Jan. 1972) lists the following:

    3964881 - 70-71 Camaro w/P/S
    3964877 - 70-71 Camaro w/Sp. H/Per.(350)(exc. P/S)
    3964851 - 70-71 Camaro (exc. Sp. H/Per., P/S)

    Dave
     
  9. mgs1971

    mgs1971 Veteran Member

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    I will not be reusing any of the manual steering stuff from my 71 if you are interested.
    Mike
     
  10. Smokin'Joe

    Smokin'Joe Veteran Member Lifetime Gold Member

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    While I believe mine to be original to the car ( I have no way to assure that it is ), My car is an 07E Built SS/396 with manual steering. I just checked and it has the 3964851 arm which is also the one referenced by Dave in the 72 Parts Catalog.

    I will try and get some pics of it and the box.

    Also, I don't remember exactly, but awhile ago I was speaking to someone and they said the manual pitman arm was one of the harder pieces to locate in steering components.


    --
     
    Last edited: Jul 10, 2013

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