If the portioning valve is from CPP you can disconnect the rear brake line from the proportioning valve and manually reset the slide valve using a small screw driver. CPP has a write-up on their site how to do this. They also sell a plug to replace the sensor switch on the proportioning valve when bleeding, to prevent this from happening, cost is about $10.
You would think they would just include it in the kit (like an alignment tool when you buy a clutch and pressure plate).
