Warning: When working with compressed air, wear eye protection. Clean the shaft oil passages with a pipe cleaner or similar.
2. Check the connecting rod and main journals through filters or the crankcase ventilation system. They can get into the oil and along with it - into the bearings. These can be metal filings from mechanical processing or normal wear products for uneven wear, scoring, cracks or point wear.
3. Rub the shaft journals with a copper coin. If copper marks remain on them, the surface is too rough (see Fig. 14.3).
4. Remove burrs from the oil channels using a file, scraper or emery wheel.
5. Measure the diameters of the main and connecting rod journals with a micrometer and compare the results (see Technical Requirements) (see Fig. 14.5).
6. To detect out-of-roundness, measure several diameters on each circumference of the neck. To detect taper, measure along the edges of the neck near the cheeks.
7. If the shaft journals are damaged, tapered or out of round, or excessively worn (see Technical requirements), then you need to hand the shaft over to specialists. They should return you a reground shaft together with the repair size liners.
8. Inspect the journals under the seals at both ends of the crankshaft for wear and damage. If there are deep grooves on these surfaces made by the seal, contact specialists. In this case, it may be possible to repair the shaft, otherwise it will have to be replaced.