Brakes, front/rear balance problem

[Tomme]

Hi!

I have problems with the front rear brake balance on my 1970 C20 with stock power drums, rear brakes locks before front.

I have adjusted the brake shoes as good as i can, but the problems stays.
The rear brakes locks easily on asphalt but not the front, although the shoes are new and the wheel cylinders seems to work ok.

I am now suspecting an internal leakage in the master cylinder.
I have not found a new master cylinder here in Sweden, so i have just replaced the gaskets in the old cylinder, there where some marks that was not possible to hone away, so i will possibly still have some problems.

One thing that came to my mind is the routing of the brake lines, if it matters wich outlet on the cylinder the lines for front and rear are connected to.

On my car the lines to the front brakes are connected to the front port of the cylinder, and the rear brakes to the rear port.

Can this possibly be wrong?
Does it really matter on an all-drums car?

I have contact with a guy who claims to have disc brake spindles from a -72 C20 with 8 bolts, so i might consider a swap on my truck.

Any comments on possible causes to my balance problems are much welcome.

Regards
Tomme