M20 PLT STRIKES TREE TOPS ON LDA DME APCH AND EXPERIENCES PRIMARY VACUUM SYS FAILURE ON MISSED APCH.

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AT APPROX XA00 HRS (LCL TIME) WHILE ON A LOC APCH TO RWY 34 AT ZZZ; I DEVIATED FROM THE INST APCH PROC DUE TO GYRO INST FAILURE (VACUUM) WHICH CAUSED SOME DISORIENTATION ON MY PART. WHILE ON A FLT FROM ZZZ1 TO ZZZ; I CHOSE TO MAKE A LOC APCH INTO RWY 34 AT DRAKE FIELD. I WAS ON LOC; A LITTLE BELOW THE GS ABOUT 1 MI FROM THE TOUCHDOWN ZONE. MY WIFE (PAX) WAS LOOKING OUT THE WINDOWS TO SEE GND (WE WERE IN THE CLOUDS). MY WIFE HOLLERED 'TREES.' I WAS WATCHING THE ACFT INSTS. UPON HER EXCLAMATION; I GAVE FULL THROTTLE AND PULLED BACK ON THE YOKE. I HEARD THE NOISE OF SCRAPING TREE TOPS ON THE ACFT. I LOOKED BACK AT MY INSTS AND THE ACFT ATTITUDE INDICATOR HAD TUMBLED AND MY DIRECTIONAL GYRO WAS SPINNING TO THE R AND TAKING THE ACFT WITH IT. I DISCONNECTED THE AUTOPLT AND GAVE L AILERON AND KEPT CLBING. I TURNED ON THE ACFT'S BACK-UP VACUUM AND USED THE ACFT BANK AND TURN COORDINATOR AND ALT INDICATOR TO CONTINUE A STRAIGHT CLBOUT. I CONTACTED TWR AND DECLARED A MISSED APCH. TWR TURNED ME BACK OVER TO APCH. APCH ASKED MY HDG. I INFORMED APCH I DID NOT KNOW MY HDG BECAUSE I HAD A LOSS OF VACUUM PRESSURE. APCH TOLD ME TO KEEP WINGS LEVEL AND CONTINUE CLBING TO 5000 FT; WHICH I DID. AFTER A WHILE; THE ACFT'S ATTITUDE INDICATOR AND DIRECTIONAL GYRO BEGAN WORKING CORRECTLY WITH THE AUX BACK-UP. I INFORMED APCH THAT I HAD HIT THE TREE TOPS ON MY APCH AND THAT THE ACFT'S INSTS WERE NOW WORKING CORRECTLY. I TURNED OFF THE BACK-UP VACUUM AND THE VACUUM STAYED UP ON ORIGINAL VACUUM. (I HAD JUST HAD A NEW VACUUM PUMP INSTALLED 3 DAYS PRIOR TO THIS INCIDENT.) I WAS VECTORED BY APCH TO ZZZ2 WITH A FLY-BY OF THE TWR TO CHK TO INSURE THE ACFT GEAR WERE DOWN. I HAD RAISED THE GEAR ON MISSED APCH AND HAD LOWERED THEM AGAIN ON APCH TO ZZZ2. TWR INFORMED ME THAT THE GEAR APPEARED TO BE DOWN; BUT THAT FIRE APPARATUS PERSONNEL SAID THE L ONE APPEARED TO BE NOT COMPLETELY DOWN. I INFORMED TWR THAT I WOULD MAKE A SLOW AND SOFT LNDG; WHICH I DID SUCCESSFULLY. I TAXIED TO THE FBO AND A MECH LOOKED AT THE GEAR AND SAID THEY WERE NOT DAMAGED AND THAT THE ACFT; IN HIS OPINION; WAS AIRWORTHY. HE REMOVED SOME TREE LIMBS AND LEAVES FROM THE GEAR BUT INSISTED THAT THERE WAS NO DAMAGE TO THE GEAR. THE 2 FAR (OUTBOARD) PANELS OF THE R WING WERE DAMAGED BY THE ENCOUNTER WITH THE TREE TOPS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT THERE WAS NO INST FAILURE PRIOR TO THE TIME THAT HE ADDED PWR AND COMMENCED CLBING AFTER STRIKING THE TREE TOPS. HE STATED THAT HE WAS JUST TOO LOW AND THAT IT WON'T HAPPEN AGAIN BECAUSE HE WILL ERR ON THE HIGH SIDE FROM NOW ON. HE ALSO STATED THAT HE WAS NOT SURE ABOUT HIS ALT AND DISTANCE AT THE TIME THE ACFT STRUCK THE TREES; BUT THAT IT MAY HAVE BEEN MORE THAN 1 MI OUT AND WAS CERTAINLY BELOW 600 FT. RPTR STATES THAT THE WX WAS RPTED AS 1700 FT BROKEN WHEN HE STARTED THE APCH BUT THAT; DURING THE APCH; HE WAS ADVISED THAT THE CEILING HAD DROPPED TO 300 FT OVCST WITH 2-3 MI VISIBILITY IN RAIN. HE STATES THAT HE ELECTED TO CONTINUE THE APCH. RPTR STATES THAT A MECH CHKED BOTH VACUUM SYS AFTER THE FLT AND THAT THERE WAS NOTHING WRONG WITH THEIR OP AND HE WAS UNABLE TO DUPLICATE THE PROB EXPERIENCED INFLT.