If your master sticks straight out from the firewall, jacking up the rear of the car will help a lot.
I have a hydraulic system from an 86 & 88 Chev 1/2 ton
Had the same problem in the 59-----
Getting ready to remove the master and when I tilted the front down to pull it out----a bunch of air had come up thru it to the resevoir.
(88 master with a remote resevoir)
Did not even crack a line and it has been just fine ever since.