Which master do you have?
Is your push rod straight so that it pushes on the piston straight?
Is the loop on the push rod installed up or down?
If it's the first gen master with the output in the middle I'd try a rebuild myself. Look up a 89 Jeep Cherokee master rebuild kit.
I've use them for rebuilds. Hardest step in doing it is getting the piston seal past the snap ring groove. I wrap the seal with ribbon with I install. Dental floss might also work well.
[This message has been edited by Dodgerunner (edited 01-30-2014).]