The excuse for not having applied penetrating fluid or similar is that there has been uncommon success here using heat for disassembly.

A DeWalt D26950 Heat Gun (equipped w/ an LCD display purporting to indicate outlet temperature) was played around the hub with the aim of raising hub temp to something approaching 100ºC – partly for the expansion growth, partly to aid in releasing any locking compound that might have been applied twixt hub/shaft. When deemed to be hottish, the heat gun was set aside and the Armature Puller was put to work.

In retrospect, I suppose the p-fluid could have been left for a time to allow the volatiles to largely evaporate.

Despite several iterations, there was no apparent movement. Eventually, luck ran out and the puller jaws damaged the hub land – what felt like possible relaxing of the hub/shaft engagement proved to be the land giving way.

Edited By Eddy Curr on 05/10/2017 16:53:50

Alas, applications of brute force under present circumstances seem likely to end in tears.

As mentioned above, the fan hub features a groove which is just 8mm in dia, w/ a 1mm shoulder to bear on.

While on the small side as pullers go, the jaws of my armature bearing puller have an inner radius ideally suited for objects of 52mm dia.

The discrepancy results in very little purchase twixt jaw and hub – while the jaw material is up to some frisky behavior, the hub material is less inclined to cooperate. Hence the desire to encircle the hub for maximum advantage and enlarge the circumference available for the puller to engage with.

At the risk of seeming close-minded, split collets of a sort that encircle the hub nearly 360º, are held together/in place with an outer sleeve that can be gripped by puller jaws and allow the push bolt to pass through the center to bear on the armature shaft preoccupy me.

Edited By Eddy Curr on 07/10/2017 18:55:25

Well, guv – you're third of three who've told me to give the hub a wallop with a BFH. So, I decided to act on your directions, Ian S C.

First, I pulled out my trusty 5 lb sledge, along with a suitable taper punch

Then I anchored the hub/armature, wound that sledge back over my shoulder and let fly, putting everything I had into the swing.

Result !!!

Not only did I drive the hub straight out the back of the molded fan …

… I propelled the hub, the bearing and the armature smack through the motor housing – extruding the shoulders of the hex on the back side of the hub past the bore for the armature bearing.

I did just what you encouraged me to do, Ian S C.

Is that the outcome you had in mind ?

What do I do NOW, oh sage one ?

Before laying on the hammer, I briefly considered electrolysis – I had success with this in the past, salvaging a length of shafting found w/ a pillow block seized in place after a lengthy time in the elements.

If applied at the beginning, maybe electrolysis might have made a difference. Turns out that the bore at the outboard end of the hub was oversize, leaving a gap between hub and shaft for some distance.

What I thought was a motor-housing-to-shaft seal (between the hub and bearing race) turned out to be a press-on locking collar – presumably to prevent bearing movement on the shaft. Like the hub, the bore of the collar was relieved, creating another gap for corrosion to grow.

The shaft bearing had seen better days.

Perhaps a contributing cause to the condition of the bearing was this feature of the fan scroll housing, a drain port leading into the otherwise sealed motor.

This drain port might also explain why on disassembly, the motor housing was found to be FULL of water and so much silt-like material that the gaps between poles of the armature were packed solid, jamming the armature within the magnets. The photo on the right below shows two trails of silt scraped from between the magnets (with a coin in foreground for perspective.)

Edited By Eddy Curr on 10/10/2017 01:08:52

To speak to the question regarding end use: automotive emissions control. Someone could be forgiven for thinking the part has come from a flood-salvage recovery or a decades-old wreck left out in a pasture. In fact, it is from an 11 yo, single owner vehicle w/ a history of just 90K km of asphalt roads. At MOST, the thing has seen a total of 600 km of anything other than asphalt in its short life.

While it resides in the e-compartment (armature vertical), the pump is not subject to HIGH temperature. The pump is commanded -ON- for short durations (seconds) at engine start-up under specific and infrequent atmospheric conditions. It draws in ambiant air and pumps this through a 600mm long molded y-hose to two solonoid-operated poppet valves (backed up by downstream reed valves for one-way flow). From each valve, 300mm stainless tubes conduct the pump's discharge air to inlets on water-jacketed cylinder heads.

On the face of it, hardly a taxing existance as auto parts go.

As to rarity, I only have an indirect measure. Forum threads (created at four sites representing 3/4's of the globe and the vast majority of english-speaking enthusiasts) just asking for a simple measurement from one of the solonoid valves went unanswered for three months and remain so, as far as I know.

New replacement pumps are available over the counter in Canada for the equivalent of GBP £500 at today's exch rate of 0.605.