As the hydraulic equipment works the level of the fluid in the reservoir rises and falls. This pulls in dirty air from the atmosphere, which is filtered by a course screen in the breather cap. The smaller contaminants enter the fluid.
One of the most hydraulic system contamination enters when oil is not filtered when fill in the reservoir.
Breather caps are very rarely if ever cleaned, the screen becomes plugged and as the result the breather cap or the filter material is removed permanently.
If left blocked, the vacuum created by the fluid moving down in the tank allows atmospheric pressure to find a way through a cracked seal or loose bolt hole. All contaminants can now enter the system.
I’ve just return form a service job. I attended to a vessel for a deck cranes pre-docking inspection.
A common thing that I find in my job is neglected device named breather cap. All the time I check the condition of the breathers and clean them wherever is possible.
Also often I checked the tank air breather filter. And this time I found this.
Records should be kept of past failures and the action initiated along with data containing details such as oil tests, oil changes, filter replacements, etc.
Basic maintenance action plan:
- Using common sense for a good maintenance. Think before act is the most important step but the one most overlooked.
- When talking about Hydraulic always try to work in a clean environment.
- Always check manual, instruction, procedure, recommendation and drawings of hydraulic equipment manufactures.
Over 70% of fault in hydraulic system are due to contamination. Filters can reduce this percentage if maintenance on them is carried out.