Page 22 - June24

MAITENANCE TIP
Grease is Good
by Dean Benedict
Take a look at the wheel bearing in Figure 1 (below) – it’s dry as a bone – there’s not a speck of grease or lubrication to be found. It looks like it sat in a solvent tank for a month, then tossed on a junk pile. The crazy thing is this wheel bearing came off a King Air during a Phase inspection in my shop years ago.
Air was a no-nonsense, by-the-book type of guy. Conscientious to a fault, he never let any detail escape his attention. Prior to coming to my shop, he’d had some bad experiences with maintenance. As a result, he was very cautious about where he took the King Air for service. He happily flew from Denver to Southern Nevada for Phase inspections. If he got stuck somewhere, he wouldn’t have anything done without consulting me first. So, I was mystified as to how those bearings dried out so fast.
The owner of this aircraft was in the pipeline business and owned a lot of equipment. He was meticulous about the maintenance
Back in the day, I had maintained this particular King Air for six or seven years when this happened. It flew about 100 hours per year and was on an annual schedule of two phases per year to ensure all four phases were completed every 24 months as stipulated in the maintenance manual.
This particular maintenance visit was for two phases, a handful of calendar items coming due, and a few customer squawks. It was looking like a very routine visit until my crew tried to remove the wheels in order to grease the bearings (as happens at every phase). They found the wheel bearings on the main gear were drier than dust. They were practically fused to the axles! My crew had to beat the wheels with a mallet to jog them loose enough for removal.
I was in disbelief. The previous year we had performed the six- year landing gear inspections. The wheel bearings were lubed properly at that time – no question about that. The aircraft flew about 100 hours since the gear was done; there was no reason for those bearings to be utterly devoid of lubrication. They were so dry they were about
20 • KING AIR MAGAZINE
to seize up. Thank goodness that didn’t happen because they would have scored the axles. I don’t want to think about the repairs necessary to remedy that situation!
The Mystery Unfolds ...
I couldn’t imagine how this happened. The pilot of this King
Figure 1: The totally dry wheel bearing, taken from the King Air referenced in the article.
JUNE 2024