A C182 ACFT LOSES ITS VACUUM PUMP; REQUIRING THE CFI FLYING THE FLT TO OBTAIN A BLOCK ALT AND A NO GYRO APCH AFTER LEAVING THEIR ASSIGNED ALT 70 NM FROM NEW DEST ARPT AT SGR; TX.

Narrative

WHILE MY ACFT WAS ON AN IFR FLT PLAN WITH A CFI AS PIC; WE EXPERIENCED A VACUUM PUMP FAILURE RESULTING IN PARTIAL PANEL CTRL IN IMC. UPON LOSS OF VACUUM PUMP THE PIC (CFI) DESCENDED FROM OUR ASSIGNED ALTITUDE IN IMC TO VFR BELOW THE CEILING; AND RPTED OUR PROB TO ATC. CFI CONTINUED FLT IN VFR WITH ATC FLT FOLLOWING UNTIL DUE TO LOWERING CEILING; WE WERE UNABLE TO CONTINUE VFR AND REQUESTED ATC ASSISTANCE. ATC PROVIDED INSTRUCTIONS TO PIC (CFI) AS TO HDGS AND ASSIGNED A BLACK ALT IN ORDER TO AVOID TERRAIN AND OBSTACLES AND TO MAINTAIN RADAR CONTACT. DUE TO PIC'S INABILITY TO MAINTAIN PRECISE HDGS WITH MAGNETIC COMPASS; ATC BEGAN A RADAR APCH FOR US TO THE ILS APCH AT SGR. CFI (PIC) INTERCEPTED ILS AND AT APPROX 1300 FT MSL; ACFT DESCENDED INTO VFR ON THE GLIDE SLOPE. ACFT CONTINUED VFR FOR A LNDG AT SGR. TWR REQUESTED THAT WE PARK AT THE SGR TERMINAL AND CALL THE TWR ON THE TELEPHONE. THE CFI (PIC) COMPLIED AND DISCUSSED THE DIFFICULTIES OF MAINTAINING HDG. NO DAMAGE TO ACFT OR INJURIES TO PAX OR CREW.