78 C-body wiper repair using B-body parts

Electrical & Ignition

  1. 71NewYorkMan

    71NewYorkMan Member

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    Many of you know that the 78 C-body intermittent 2-speed wiper system is a one year only orphan system that requires unobtainable plastic parts to repair. There is a well known and documented fix by @1978 NYB and others that describes how to use 77 and earlier c-body parts as a work around.
    1978 NYB wiper woes.
    I Am Absolutely Done With 1978 Wiper Cams

    Before I bought my 78 NYer, I suspected it would not have a functional wiper system. I read all of the posts I could find on the subject, which alerted me to a "rumor" that b-body parts could also be used as a fix. As I happen to have b-body parts as spares for my Cordoba, I decided to give it it a shot. It works! This particular solution requires no fabrication, but a minor change to the donor b-body linkage will be required.
    Some definitions-
    "Sweep"- the position of the wiper arm and direction in which the motor turns (counter-clockwise as viewed from linkage end of motor) in normal operation.
    "Stop"- the position of the wiper arm in either the intermittent or continuous "sweep" cycle.
    "Park"- the position and direction in which the motor turns (clockwise as viewed from linkage end of motor) when system is turned off.
    "Stroke"- The motor motion which changes dependent on whether the motor is turning clockwise or anti-clockwise.
    "Cam"- Plastic/metallic linkage which changes the length of "stroke" dependent on motor rotation.
    "MP"- Murray Park. A well known and respected supplier of used and reproduction Mopar parts.

    Some comparison photos for the hardware-
    My c-body motor left, NOS b-body motor right. My research indicates several different part numbers for the 78 c-body and 78-79 b-body motors, but they are ALL interchangeable.
    IMG_1294.jpeg
    Busted c-body link left, busted b-body link right. Notice the 180 degree difference in the indexing of the linkage. This difference is important!
    IMG_1185 copy.jpg
    Busted c "cam" shown on parked motor.
    IMG_1181.JPG
    Busted b "cam" on parked motor.
    IMG_1182.JPG
    Next photo shows c linkage and "cam" on top, b linkage and "cam" bottom. Both of these systems are shown in their approximate "park" positions. Notice the differences in orientation of "cam" and wiper arm mounts.
    IMG_1177 copy.jpg
    Next photo shows left to right- original busted 78 b "cam" fully disassembled, busted 1990's replacement Mopar b "cam" partially disassembled, "MP" replacement b plastic "cam" parts, my busted c "cam" assembled. IMG_1307.JPG
    Now the fix-
    I assembled the "MP" plastic parts to the b body metal base. You must reuse the base, spring, c-clip and ball shown in the disassembled original or later service issue b "cam" shown below.
    IMG_1308 copy.jpg
    My method of assembling the "MP" parts, original b metal "cam" parts, and original c-body linkage-
    IMG_1311.JPG
    Assembled c linkage with reused b "cam" and new "MP" plastic parts-
    IMG_1322.JPG
    Next is the ONE modification you MUST make- file the flat in the index hole of the b-body "cam" so that you may position the rebuilt b-body "cam" as similar to the c-body "cam"- IMG_1322 - file corner.jpg
     
    Last edited: Jun 23, 2019
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  2. 71NewYorkMan

    71NewYorkMan Member

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    My system ready for installation-
    IMG_1324.JPG
    System installed, wiper arms tinkered, and running for 30 minutes (with me wetting the windshield to prevent drag).
    Engine running, wipers off-
    IMG_1327.JPG
    Wipers on, full "Sweep"-
    IMG_1329.JPG
    Wipers on, "stop" position-
    IMG_1332.JPG
    Return to off / "park"-
    IMG_1333.JPG
    For those of you who have access to the earlier c-body parts to perform your conversion, I wish you success. If you happen to have access to b-body parts, as I have, then this becomes another option. Either way, I hope this thread has been helpful!
     
    Last edited: Jun 23, 2019
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  3. 75LandYacht

    75LandYacht Senior Member FCBO Gold Member

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    Thank you sir, Great info. On another note, what decision have you made regarding your roof? And have you done anything else to the car since her arrival?
     
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  4. cantflip

    cantflip Old Jagoff with a Hat FCBO Gold Member

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  5. 71NewYorkMan

    71NewYorkMan Member

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    Enter my post, then post another to the same thread? Got it. Thank-you!
     
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  6. 71NewYorkMan

    71NewYorkMan Member

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    I have created several threads detailing the progress. The engine is running well, a lift survey this past week generated an action list. Ultimately, the roof will return to OEM with possibly an 05-10 300 sunroof. Cantflip has offered moral support and tin for that project!
    78 NYer "Kinda"- So it begins...
    Kinda running better...
    Kinda got a lift...
     
    Last edited: Jun 23, 2019
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  7. tallhair

    tallhair Rufus "Mod Hair" Firefly Staff Member

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