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Re: JC-4 Vacuum Pump?? [message #364219 is a reply to message #323858]

Sun, 23 May 2021 21:01

RF_Burns

Messages: 2276
Registered: June 2008
Location: S. Ontario, Canada

Karma:

Senior Member

Richard,
Have you read DaveL's article in the Spring GMCMI magazine about the proportioning vales. If you have replaced your OEM with a brass proportioning valve, you may have limited rear brake pressure.

The "Mod" of the JC-4 wasn't really a high tech "Mod". I believe the internal control circuitry pulled one side of the motor to ground through a Power FET to turn it ON. I just moved wire on the switched side of the motor to the JC-4 ground pin and ran that pin through the relay to ground.... I'd have to look at it again to be sure.

Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

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[Message index]

		JC-4 Vacuum Pump?? By: rjw on Wed, 13 September 2017 21:08
		Re: [GMCnet] JC-4 Vacuum Pump?? By: k2gkk on Wed, 13 September 2017 21:36
		Re: [GMCnet] JC-4 Vacuum Pump?? By: Jerry Wheeler on Wed, 13 September 2017 22:24
		Re: [GMCnet] JC-4 Vacuum Pump?? By: rjw on Thu, 14 September 2017 06:11
		Re: [GMCnet] JC-4 Vacuum Pump?? By: USAussie on Thu, 14 September 2017 07:18
		Re: JC-4 Vacuum Pump?? By: Larry on Thu, 14 September 2017 07:33
		Re: JC-4 Vacuum Pump?? By: Hal StClair on Thu, 14 September 2017 11:31
		Re: JC-4 Vacuum Pump?? By: larry.whisler on Thu, 14 September 2017 16:30
		Re: [GMCnet] JC-4 Vacuum Pump?? By: Ken Henderson on Thu, 14 September 2017 17:55
		Re: [GMCnet] JC-4 Vacuum Pump?? By: johnd01 on Fri, 15 September 2017 00:32
		Re: [GMCnet] JC-4 Vacuum Pump?? By: Ken Henderson on Fri, 15 September 2017 06:10
		Re: [GMCnet] JC-4 Vacuum Pump?? By: GatsbysCruise on Sun, 23 May 2021 12:18
		Re: JC-4 Vacuum Pump?? By: jhbridges on Thu, 14 September 2017 17:12
		Re: JC-4 Vacuum Pump?? By: RF_Burns on Sun, 23 May 2021 13:45
		Re: JC-4 Vacuum Pump?? By: rjw on Sun, 23 May 2021 14:43
		Re: JC-4 Vacuum Pump?? By: RF_Burns on Sun, 23 May 2021 21:01
		Re: JC-4 Vacuum Pump?? By: rjw on Mon, 24 May 2021 06:05

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