Front Disc conversion. Rear Drum brakes locking up

[FIFTYFIVE210]

Hi,

Have a front disc brake kit installed on a 57 chev.
Rear brake cylinders were seized and now replaced. Now rear drum brakes are locking up first.
Any suggestions?
How do I adjust the proportioning valve if it is that?

Dave

I know this is an old thread, but I was wondering if you found a solution to this. I have the same problem with my '55 chevy. Disc front, stock drums in rear. Thanks

[Dcastle]

This is exactly the crappy advice CPP will give you after they send U the wrong parts. Of course the proportioning valve could be defective or incorrect !!!!!

[80 Elcamino]

If you have not fixed yor problem yet, you might have to much pressure to the rear brakes. One possible solution is to install a adjustable proportioning
valve and decrease pressure to rear brakes