91 safari AC

hello, the problem is about a 91 safari with rear ac system.

I charge the system with r134a. Now, the compressor runs fine for about a minute, then starts to spray liquid/gas from the behind of comressor (pressure safety swithc i beileve).

What might be the reason? my guesses are:

1. bad comressor
2. clough pipe (does it have any filter in the hose, or what is the best location to track down the problem. )

TIA