A B C D E Figure 5-51.  Representative types of repairable and nonrepairable landing gear assemblies.  The landing gear assembly type D is generally nonrepairable  for the following reasons: The spring-steel leaf, shown as type E, is a component of  a standard main landing gear on many light aircraft. The  spring-steel part is, in general, nonrepairable, should not be  welded on, and should be replaced when it is excessively  sprung or otherwise damaged.  Streamline tubing, used for some light aircraft landing gear,  may be repaired using a round insert tube of the same material  and having a wall thickness of one gauge thicker than the  original streamline tube and inserting and welding as shown  in  Figure 5-52. 1.  The lower axle stub is usually made from a highly  heat-treated nickel alloy steel and machined to close  tolerances. It should be replaced when damaged. 2.  During manufacture, the upper oleo section of the  assembly is heat treated and machined to close  tolerances to assure proper functioning of the shock  absorber. These parts would be distorted by any  welding repair and should be replaced if damaged to  ensure the part was airworthy. 5-35