Occasionally, even the highest quality grease guns will stop dispensing grease. The culprit: entrapped air at the head chamber of the gun. There are several ways to remove this air. Some guns have a small button valve that allows the air to escape. Others have a small hole that becomes exposed when the head is loosened from the barrel about 1/4 to 1/2 turn. Work the lever of the gun when performing these procedures.

You will be able to tell when the air has escaped because the resistance in the lever will change when grease enters the pumping chamber. Another method that sometimes works is by striking the plunger handle of the gun on a hard surface several times while holding the gun vertically with the head upward. (Michael Lofald, Predictive Maintenance Manager, SAPPI Fine Paper)

Join us in Las Vegas for Machinery Lubrication Level I training on September 20-22 followed by ICML Level I MLT certification on September 23.

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Book Bits: Evaluating a Hydraulic Repair Shop

From "Insider Secrets to Hydraulics"

Regardless of whether you decide to use the machine dealer, the hydraulic component manufacturer or an independent for your hydraulic repairs, you should always inspect the facilities first.

Beyond the basics such as a clean, dry environment, you should satisfy yourself that the repairer has the necessary facilities to carry out the majority of the work in-house and test the component once it has been rebuilt.

If the repair shop must rely on outside suppliers to carry out a large portion of the rebuild process, you are likely to end up paying too much for the repair. This is due to the margins of these suppliers being built into the price you pay for the rebuild. For example, if you send a cylinder to a repair shop that has to use outside suppliers for any welding, machining, rod straightening or chroming, their repair price is likely to be more expensive than a repair shop that has the capability to carry out these processes in-house.

More information about the book "Insider Secrets to Hydraulics"

Test your knowledge and prepare for ICML lubrication and oil analysis certification.

QUESTION: When water contamination in oil is below its saturation point, the water is in what state?

Get the answer.

"Is it really necessary to drain and flush my machine sumps when making a change to an alternative lubricant vendor?"

The simple answer is yes. However, if you are dealing with large volumes and a significant investment, you may avoid the risk of NOT dumping the sump contents. This is what you need to do:

1. Assess the fluid condition of the fluid in place. RPVOT is a useful tool for verifying residual lifecycle. If the fluid is nearly spent, proceed with the complete change.

2. If fluid life is good, repeat the RPVOT test in portions of 90/10 and 50/50 to see what impact the mixing of the lubricants would have on lubricant health. At the same time, it is useful to run demulsibility, air entrainment and foam tendency tests to assess the ability of a blend of lubricants to dissipate contaminants such as water and air. A simple visual check of oil cloudiness or suspensions is also useful.

3. If the system requires filtration, then perform filterability tests on the mixtures, at the same ratios. If these preliminary tests offer no evidence of performance loss, you could consider proceeding with a top-up approach.

Mike Johnson, Noria Corporation

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