The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Minimal rear brakes...Proportioning / combination valve fun and education.

**geunther** · 12-25-2016, 11:18 AM

The pin moves because of pressure differential. If one side in the cutaway loses pressure, the pin will move to that side by the combination of vacuum on the low pressure side and pressure on the side that is still functioning properly.

The pick method of reentering can be difficult, but have had pretty good luck doing it that way. The special tool would be helpful. The tool that threads into the sensor hole does a decent job of holding the differential switch centered while bleeding.

12-25-2016, 11:18 AM	#6
geunther Senior Member Join Date: Apr 2005 Location: Cheyenne, WY Posts: 740	Re: Minimal rear brakes...Proportioning / combination valve fun and education. The pin moves because of pressure differential. If one side in the cutaway loses pressure, the pin will move to that side by the combination of vacuum on the low pressure side and pressure on the side that is still functioning properly. The pick method of reentering can be difficult, but have had pretty good luck doing it that way. The special tool would be helpful. The tool that threads into the sensor hole does a decent job of holding the differential switch centered while bleeding.