http://www.minimania.com/article/1641/F ... r_-_GMC227
Ok, just read the Minimania page on the master cylinder and the diagram on the page clearly shows the upper brake line running to the front brakes & the lower line going to the rear.
So I think you have your brake lines back to front from the MC to the pressure reducing valve! This will give more pressure to the rear brakes than the front.
With what we all have said up above it make sense!
Increase the master cylinder bore size and decrease pressure at the brakes but move more fluid. The rear needs more fluid, so they go to bottom of the MC with the larger bore size, and the front needs more pressure than the rear, so the upper outlet of the MC with the smaller bore size goes to the front.
Hope this helps!
Cheers Shane
