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GT6 What's the purpose of the ball bearing in the PDWA switch?

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brgrmyster

brgrmyster

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Folks,
I'm in a friendly debate with a friend over the purpose of the small ball bearing in the Girling PDWA two-piece switch from my 1968 Triumph GT6 Mk1(see photo). I say that it is to provide a firm ground for the PDWA shuttle when it moves left or right based on a pressure change, thereby pushing in the contact pin on the electrical switch. I assume the two piece shuttle is free floating on O ring seals within the shuttle journal, and therefore not touching metal. The ball bearing is the only way the shuttle continually is in contact with the PDWA switch itself, which is grounded through attachment to the firewall. My friend disagrees, yet can't fathom what the purpose of the ball bearing is.
Opinions???? Answers???
Regards,
Jeff
 

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  • PDWA Ready for Rebuild (1).jpg
    PDWA Ready for Rebuild (1).jpg
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Figured this out folks. Looking at section 6-208 Figure 9 of the GT6 MK1, 2 & 3 and Vitesse Workshop Manual, it appears the ball bearing is dropped down the hole where the electrical switch with plunger is installed. The plunger end rides on the ball bearing, which is centered precisely on the shuttle center. Presumably, if the shuttle moves left or right the ball will spin, reducing friction at the very tip of the electrical switch plunger. I gather the shuttle will move left or right without it. Anyway, I think the ball bearing conumdrum is solved.
brgrmyster said:
Folks,
I'm in a friendly debate with a friend over the purpose of the small ball bearing in the Girling PDWA two-piece switch from my 1968 Triumph GT6 Mk1(see photo). I say that it is to provide a firm ground for the PDWA shuttle when it moves left or right based on a pressure change, thereby pushing in the contact pin on the electrical switch. I assume the two piece shuttle is free floating on O ring seals within the shuttle journal, and therefore not touching metal. The ball bearing is the only way the shuttle continually is in contact with the PDWA switch itself, which is grounded through attachment to the firewall. My friend disagrees, yet can't fathom what the purpose of the ball bearing is.
Opinions???? Answers???
Regards,
Jeff
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