THE RIGHT MAIN LANDING GEAR COLLAPSED DURING A LANDING AFTER SEVERAL ATTEMPTS WERE MADE TO LOCK THE GEAR INTO THE DOWN POSITION. AFTERWARDS, WHEN THE AIRCRAFT WAS ON JACKS AND THE ROD END DISCONNECTED, THE LANDING GEAR WAS RETRACTED AND THE DRAG LINK LOCKED DOWN OVER CENTER AND MET TOLERANCE. DURING THE RETRACTION THE DOWN LOCK SWITCH COULD BE HEARD TO CLICK PRIOR TO THE DRAG LINK LOCKING OVER CENTER. DAMAGE TO THE LANDING GEAR, EXCEPT FOR THE ROD END, WAS IMPACT DAMAGE FROM THE COLLAPSING GEAR.