hiwy50 Posted September 21, 2015 Share Posted September 21, 2015 Is a B model Mack negative or positive ground?? THANKS Richard Quote Link to comment Share on other sites More sharing options...
Mack458 Posted September 21, 2015 Share Posted September 21, 2015 My 65' is positive ground and I believe most of them were. Quote Link to comment Share on other sites More sharing options...
41chevy Posted September 21, 2015 Share Posted September 21, 2015 My 1961 is positive too Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment Share on other sites More sharing options...
Brian Blaylock Posted September 21, 2015 Share Posted September 21, 2015 Mack diesels were positive ground until the mid-seventies then they were changed to negative but look close it could have been changed especially if it has been changed from generator to alternator Quote Link to comment Share on other sites More sharing options...
41chevy Posted September 21, 2015 Share Posted September 21, 2015 Mack diesels were positive ground until the mid-seventies then they were changed to negative but look close it could have been changed especially if it has been changed from generator to alternatorDouble check it if it does! My B has a positive ground one wire alternator made by Quality Power. Only dumb luck that I didn't assume it was Negative ground when I did new batteries. 1 Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment Share on other sites More sharing options...
Dieseldriver65 Posted September 21, 2015 Share Posted September 21, 2015 I think they changed in the "80's?I know they went way longer than others! 1 Quote Link to comment Share on other sites More sharing options...
hicrop10 Posted September 22, 2015 Share Posted September 22, 2015 What was the reason for the positive ground and not negative? Quote Link to comment Share on other sites More sharing options...
Bigdogtrucker Posted September 22, 2015 Share Posted September 22, 2015 My B75 was converted to negative ground in "02 when the owner bought a new Interstate lowboy. ABS would not work otherwise. Quote Link to comment Share on other sites More sharing options...
41chevy Posted September 22, 2015 Share Posted September 22, 2015 What was the reason for the positive ground and not negative?Henry Ford and Thomas Edison thought that a negative ground system degraded the early copper wires and the copper electrical components. If Edison felt that way it must be true. Better metallurgy and better insulation (plastics) got rid of that system. 1 Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment Share on other sites More sharing options...
b61mack Posted September 22, 2015 Share Posted September 22, 2015 My 77 R686 was negative ground from the factory, the 76 R686 we had was positive ground, I switched it over to negative. Quote Link to comment Share on other sites More sharing options...
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