As described in earlier service letters(SL87-219, SL90-272 and SL90-273),AlSn40-based crosshead bearings must urgently be replaced as soon as possible if an open-up inspection shows morethan 5% of the nickel layer exposed. If one bearing unit has more than 5% of the Ni-layer exposed, it is very likely that all the other units suffer from a similar extraordinary wear, and they should therefore be replaced as well.To decide which bearings to inspect first, all top clearances should be measured and compared with the shop test/sea trial records. If large deviations are found, and/or if bearing “dust” is found in the surrounding area in the frame box, those bearings should be the first to be inspected.