The 1900cc water boxer engines (WBX) were upgraded in October 1985, during which, among other things, the thrust bearing was changed from a bearing with two raised edges to a bearing without these edges, which were replaced by thrust rings. The 2100cc engines were equipped with thrust washers in front of and behind the thrust bearing from the beginning.
These rings or washers must be replaced at the same time as the bearings, so you will always have to order them to overhaul the engine. Reusing old washers is not an option, after all you don't reuse old main bearings either.
If you have a pre-October 1985 engine, the crankcase may have been replaced by Volkswagen. In this case, the crankcase has the part number VW 025 101 025 A, a crankcase that was used as standard after October 1985 and therefore uses an axial bearing with separate thrust rings.
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