The Stovebolt Site Forums The Parking Lot Big Bolts BRAKES ON A 1953 6400

Are you following the bleeding procedure in the Shop Manual. In particular, the procedure for bleeding the hydrovac unit (before bleeding the wheel cylinders)?

http://chevy.oldcarmanualproject.com/shop/1954truck/54ctsm0527.html

I would guess that your 1953 should be bled as described for a '54 Chevrolet truck with a hydrovac unit.

The procedure described in the GMC maintenance Manual is slightly different, but the hydrovac unit is also bled first.