The Jargon File (version 4.4.7, 29 Dec 2003):

hack up
 vt.

    To hack, but generally implies that the result is a hack in sense 1 (a
    quick hack). Contrast this with hack on. To hack up on implies a 
    quick-and-dirty modification to an existing system. Contrast hacked up;
    compare kluge up, monkey up, cruft together.


The Free On-line Dictionary of Computing (30 December 2018):

hack up

    To hack, but generally implies that the result is a
   quick hack.  Contrast this with hack on.  To "hack up on"
   implies a quick-and-dirty modification to an existing
   system.  Contrast hacked up; compare kluge up, monkey
   up, cruft together.

   [Jargon File]

   (2003-09-02)