On March 18, 2009, at 1321 eastern daylight time, a Cessna 310K, N6901L, registered to a private owner, operating as a Title 14 Code of Federal Regulations Part 91 instructional flight, experienced a right main landing gear collapse on landing roll at Ocala International Airport (OCF), Ocala, Florida. Visual meteorological conditions prevailed and no flight plan was filed. The airplane received substantial damage. The commercial pilot flight instructor (CFI), and private pilot owner receiving instruction reported no injuries. The flight originated from Dunnellon Marion County and Park of Commerce Airport (X35), Dunnellon, Florida, at 1245. During a prior flight, the private pilot stated he made a straight in approach to runway 5 at X35. He "flared a little high, the airplane hit the runway a little hard, bounced, and he initiated a go-around. He entered left downwind and landed with out incident." The CFI described the landing as firm. The private pilot departed X35 and noticed a no landing gear up and locked light on climb-out. He recycled the landing gear with negative results. He contacted the fixed base operator at OCF and asked if someone could observe the landing gear while he made a low pass over the airport. During the low pass, ground personnel informed the pilot that the left main landing gear appeared to be partially extended, while the nose landing gear and right main landing gear appeared to be fully extended. The pilot over flew the airport to the north and transferred the flight controls to the CFI. The private pilot read the emergency procedures in the operator's manual and reset the circuit breaker for the landing gear motor. The left main landing gear and nose landing gear green light illuminated. The right main landing gear light did not illuminate. The private pilot then continued with the emergency procedure. The private pilot thought the right main landing gear position light bulb was bad or there was a problem with the electrical system. The private pilot assumed control of the airplane, and returned to the airport for another low pass. Personnel on the ground informed the pilot that all landing gear appeared to be extended. The private pilot entered left closed traffic and landed. The right main landing gear then collapsed during the landing roll out. Examination of the airplane by a Federal Aviation Administration inspector and airframe and power plant mechanic revealed that the left wing spar was buckled. The right main landing gear forward pivot shaft retaining clamps were missing and not recovered. The forward pivot shaft remained installed in the bearing and was bent. The aft retaining shaft was pulled from the bearing and was bent downward at a 90-degree angle, and the shaft was secured to the strut assembly by the retaining clamps. The upper side link was broken and the outboard push-pull tube was bent. The bent push-pull tube restricted the operation of the landing gear. When the push-pull tube was removed the landing gear retraction mechanism worked when the landing gear was cycled. The private pilot informed the mechanic, "that he had a hard landing while doing touch and go's at Dunnellon Airport just before returning to Ocala."