Lubrication failure
Three lubrication routes to a failed bearing: too little, too much, too dirty
Under-lubrication, over-lubrication and contaminated lubrication each leave different clues on the bearing and on the housing.
The three routes
| Route | What happens | What you see | Remedy |
|---|---|---|---|
| Too little (or too old) | The film breaks into boundary lubrication and the surfaces touch | Smeared or discoloured tracks, adhesive wear, blue heat marks, dry dark grease | Check the interval and the quantity. Consider automatic lubrication on hard-to-reach points |
| Too much | The bearing churns the grease and heats up, and grease forces past the seals | High temperature, grease pushed from the seal, softened grease | Grease by calculated quantity with a meter. Fill only a controlled share of the housing free space |
| Too dirty | Dust, sand and water form a grinding compound | Dull, scored tracks, gritty grease, rust and etching | Improve the seals, add purge grease, grease frequently in small doses |
Proof, not guesswork
Both too little and too much are quantity errors, and a hand gun cannot control quantity well. A grease meter, or an automatic system, is the practical fix.
Contamination is the quiet one
Dust and water get in even when everything looks sealed. The signs are in the grease and in the track, and a grease or oil sample often shows it long before the bearing runs noisy.
Takeaway. Before you blame the bearing, find out which of the three lubrication routes it took.
Put it to work in the tool