Fan Hub Bearings

At the Gathering at Gilmore meet last weekend there were two failures of the fan hub bearing on our member’s cars.

One on a car being driven to the Gathering, and one on the tour on Saturday.

The fan hub bearing is a long bushing on the ’29 and later engines. This long bushing rides on the shaft we can see between the bearing assembly and the eccentric mount on the front of the engine. The hub has a round reservoir to hold oil to lubricate the bushing. This reservoir does not have a typical seal. It has a gap between a slinger [rotating round ring] and the shaft.

When the reservoir is filled, the oil level will be lower than the gap between the slinger and the shaft. But the internal parts do allow some oil to get on the shaft and past the gap and then all over the engine and underside of the hood. The slow inevitable loss of oil can catch us, the car owner/driver unaware.

The fan hub bearing’s oil level cannot be ‘checked’, it can only be filled by the normal process. Since this is a bit of a bother, most of us don’t fill it very often. And unfortunately, this leaves the bearing without adequate lubrication and eventual failure of the bearing.

For many years, a lot of PAS members have had their fan hubs modified to use modern, sealed ball bearings. This works well, since this type of sealed bearing typically run for over 100,000 miles in modern car alternators and other applications. But this modification required taking the fan assembly off and shipping it to a machine shop familiar with the modification.

Thankfully there now is a much more convenient way to accomplish this modification and repair.

John Cislak has had a hub made from a solid billet of aluminum, with sealed, permanently lubricated bearings, new shaft, and all the proper holes drilled. This hub assembly makes updating your Pierce’s fan bearings MUCH easier than in the past. There is only normal wrench and screwdriver skills needed for installation, with the exception of needing to remove the no-longer-needed oil slinger. I used a dremel with a small cut-off wheel to remove my oil slinger.

This hub assembly is available for all 6 or 7 versions of the Pierce fan hub, and they are reasonably priced.

I recommend that anyone who drives their Pierce Arrow cars to consider installing either the hub assembly that is mentioned above, or have a machinist modify your hub, or religiously fill your fan hub reservoir.

I do fill my fan hub reservoirs ‘sort-of’ religiously, and did on my cars I took to the Gathering. Yet when we elected to drive one of the cars the 120 miles from the Gilmore back home, I nearly had a similar bearing failure. Checking the car upon arrival at home I noticed that the fan bearing had become very sloppy and there was oil slung all over the front of the engine. and the fan bearing was very loose and sloppy.

So, I’m installing a sealed-bearing hub assembly I purchased from John C last Fall at Hershey. Thankfully I was not stranded on the highway last Sunday.

Greg Long