Abstract: The pivot or hinge joints of a track chain assembly of a track laying tractor each include lubricant cavities which are sealed by a pair of spaced apart seals. The seals each include a resilient rubber load member and a relatively rigid polyurethane seal member having an annular sealing lip which is biased into place by the load member when the seal is installed. The effectiveness of the seals is tested by adding a coloring agent or dye to the lubricant in the cavities being sealed, by operating the assembled chain in a mud box for a predetermined time, by disassembling the chain and then by inspecting the seal members to see whether or not surfaces thereof normally outside the sealed cavity have been contacted by leaking lubricant as evidenced by the presence of the dye.

Abstract: A sealed joint assembly interconnecting links of crawler tractor track chain includes an annular sealing member made of relatively rigid abrasion resistant material formed to define contiguous axially and radially extending bands, the sealing member thus being generally right angular in cross section. The radially extending band includes a pair of surfaces which converge axially to form an annular edge which engages an end surface of a track bushing and is in fact biased theretowards by means of an annular compressive load member made of resilient relatively pliant material of generally rectangular cross section loaded predominantly in compression between the bottom of a counterbore of one of the links and the sealing member. A spacer ring is located radially inwardly of the axially extending band of the sealing member and augments the band in restraining radially inward expansion of the load member.