'70 Z-28 Manual Steering

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

  1. 70lt1z28

    70lt1z28 Veteran Member Gold Member

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    I believe the A or B may be the forging die cavity identifier. Speculation on my part but this is common in the industry.
     
  2. fdeluca532

    fdeluca532 Member

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    I have a manual steering center link if your interested
     
  3. 70 Six Banger

    70 Six Banger Member

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    DSCF4179.JPG DSCF4180.JPG DSCF4161.JPG DSCF4162.JPG I know this is over a year since the last reply, but manual steering on a 2nd Gen Camaro is pretty rare (almost non-existent), so sometimes it takes a year before someone with pertinent information adds to the thread. Anyway, I digress...

    I have a '70 Camaro with a 6-cylinder and manual steering and thought you might appreciate some pictures of the setup and the number on the steering box. It has a "5679142" box, which is the same manual box that came on early Z28s and may have come on '70 Zs. I can't determine the Pittman Arm's part number, but I'll clean it up with some carb cleaner when the weather warms up a bit here and I can crawl under the car. I haven't been able to determine a date code for the box, but will try to clean it up and get that on here.

    I'm attaching a page from the '70 AM that says the Z and cars equipped with a 6 and manual steering used the 7807761 box. I know the 5679142 box was a leftover from the '69 Z and possibly replaced the 7807761 box or was used until that box took over. My car was built 05D...about halfway thru '70 production. I can personally attest that my car handles great on twisty roads.
     
    Last edited: Feb 15, 2021
  4. 70 Six Banger

    70 Six Banger Member

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    I was able to clean the Pittman DSCF4186.JPG arm off enough to see that it has a GM part number on its underside. I will have to do some more cleaning to fully reveal the number. As you can see from the flash picture, the letters "GMT" are clearly visible, but the rest of the number will require some more carb cleaner and a soft brass bristle brushing to be full revealed. The center hole to center hole distance appears to be approx. 5.6 - 5.8", which would indicate it is the correct length for a non-HP application using the 5679142 box. Once I have the numbers off the arm I'll post them.
     

    Attached Files:

  5. 70 SS/L78

    70 SS/L78 Veteran Member Lifetime Gold Member

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    Does your steering box have an aluminum cover? I believe the Z28 manual steering box used an aluminum cover whereas other models did not.
     
  6. Rosster

    Rosster Veteran Member Gold Member

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    Yes mine has the alum cover. The z28 also has a faster ratio than other non-Z manual boxes. Not sure of it was done via longer pittman arm or internal gears though.
     
  7. 70 Six Banger

    70 Six Banger Member

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    L78 and Ross...my car's steering box has the aluminum cover which is still mostly covered with the original chassis black factory paint. I looked at 5679142 steering boxes listed on Ebay and discovered that the cast iron covers are embossed with "CHECK LUBE" and casting numbers, whereas the aluminum covers are completely smooth. I will be taking the box apart this spring to completely clean out 51 years of accumulated crud, then relube it and reseal it. Possibly the internal worm gear is the same as the '70 Z but simply uses a longer Pittman arm. Attached photos will show the differences. DSCF4189.JPG DSCF4190.JPG
     
  8. 70 Six Banger

    70 Six Banger Member

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    I just looked at the page I posted above from the '70 AM...note that it lists a "Gear Asm" with GM part number 7809504 as item number 1...right above the steering box (GM 7807761), which is also listed as item 1...they were assembled with the same gears, so the difference between the '70 Z and a '70 6-cylinder car's manual steering boxes was the Pittman Arm length. I don't know if this same gear/box situation exists with the 5679142 box, but I suspect it does. Does anyone on here have a 7807761 manual box, and if so does it have 3 or 4 mounting bolts?...I have been looking for a photo of that box but have had no luck.

    I had been toying with the idea of swapping a factory power steering setup into my car, but it drives just fine with the manual steering and I now realize it's too rare and unusual to change it.
     
    Last edited: Feb 15, 2021
  9. DCL70

    DCL70 Veteran Member

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    Sometime last year I sold my 1970 Camaro M/T steering box (6 5/8 turns, lock to lock), casting "5679142", stamped "B1320" (2nd shift, 132nd day of 1970), and with "113" casting day (113th day of 1970, I assume). It had "GMT3 3964881A" on the pitman arm. The pitman arm measured about 6 7/8" C/C of the 2 holes. The small tapered hole measured about 0.66" and 0.58" in diameter. The large splined hole measured about 1.03" and 1.08" in diameter. I have 13 photos of the steering box in my files, attached are 4 of them.
    Dave

    70 Camaro Streering Box - 1 of 13.jpg 70 Camaro Streering Box - 2 of 13.jpg 70 Camaro Streering Box - 3 of 13.jpg 70 Camaro Streering Box - 6 of 13.jpg
     
  10. 70 Six Banger

    70 Six Banger Member

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    Wow Dave...that's the exact '70 Z28 manual steering box and Pittman Arm that is now basically unobtanium...thanks for posting it! I can now see that my steering box was cast on the 90th day of 1970 (see photo from my first posting in this thread). When I pull my steering box apart for cleaning I will see if there are any GM numbers or ratio numbers cast into the gears. I wonder what percentage of '70 Zs had manual steering...any way to determine that?

    I appreciate the level of research you put into your posts...thanks.
     
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