The certified flight instructor (CFI)and pilot receiving instruction were on a training flight practicing touch and go landings. The pilot receiving instruction made a touch and go landing, and remained in left closed traffic for another touch and go landing. The airplane touched down on the runway and the CFI retracted the flaps. The pilot receiving instruction added power and the airplane pulled to the right. The CFI thought the airplane had a flat tire and took over the flight controls. The airplane continued turning to the right and the CFI lost directional control of the airplane as the right wing dropped down and struck the runway. The airplane went off the right side of the runway 100 feet and came to a complete stop. Examination of the crash site by the FAA revealed the airplane touched down about 150 feet from the displaced threshold. Transfer marks from the right main landing gear were present on the runway and extended 600 feet down the runway, and were observed to veer to the right. Propeller slashes from the right propeller were present on the runway. In addition, paint transfer marks from the right wing were present on the runway, and where the right main landing gear had collapsed. Review of the aircraft logbooks revealed a mechanic had installed new scissors bushings on the airplane on December 18, 2007. Examination of the right main landing gear revealed the wide area washers had not been installed under the bolt head as required by the maintenance manual. These washers keep the scissors from sliding off the bushings at the attachment point. The mechanic performing the maintenance installed the washers on the wrong side of the scissors. After the second touch and go landing the scissors separated and the wheel began to move around loosely setting up a vibration and the right main landing gear collapsed.