A contract maintenance Mechanic is informed he did not install the inboard axle spacers on the left and right nose tires on a B767-300.

Narrative

Pilots reported nose gear shimmy on landing. Removed and replaced nose gear tire assemblies left-hand and right-hand per Maintenance Manual 32-45-02 and task card. Upon removal of nose gear tire assemblies; no shims/spacer were present. The nose gear assemblies installed; did not contain spacers either. In ZZZ; upon landing; the shimmy occurred and upon inspection the technicians found no shims or spacers installed. Reworked tire assembly installation with shims and spacers. No further discrepancy occurred. Contributing factors: The original nose gear tire assemblies did not contain the required spacers; weather was cold at 25-30 degrees F that night; heavy workload with only 2 technicians working; and poor lighting in area of work. Callback conversation with reporter revealed the following information: Reporter stated the B767-300 had arrived with a nose wheel shimmy problem. The confusion started when neither of the spacers were present when they removed both nose tires. Reporter stated the maintenance paperwork does refer to the two different types of threaded axles; one being internally threaded and the other externally. This nose gear had the externally threaded type of axle that required the inboard spacer for each tire. Reporter stated the maintenance pictures do not show a good view of the different axles; and since the aircraft came in with both spacers missing; he and his partner decided the axle spacers were not required.