Jonesy,
Just trying to understand your machine better.The more information you supply the better the chances someone can help you.As the guys have mentioned above the vane pass frequency in your data that you displayed doesn't seem to be the source of your vibrations. The 28Hz displayed in the data would indicate this is happening at 1X fan rotational speed. Have you checked the machine hold down bolts for movement?
Newcastle,NSW, Australia (East Coast) Yes that is right. Are you local to this area?

Hooch,
yeah I've been all over this thing but the only thing that really grabs me is that rusty coloured grease at the D.end brg on the fan shaft, so i think as previously mentioned in this post we'll be looking at a new shaft and housing.
I'm up in Oberon, but frequent Swansea a bit

I bet you are a little cold today, have you got snow yet?
Last time I was down your way I got several flat tyres in the Kanangra Boyd area it was summer in 2000.
Evidence is starting to suggest the bearing has got hot at some stage. levels seem to be low have you retested this fan yet?

I dont think the brg has overheated, but ive been wrong before, probably the small amount of clearance has created wear particles and rusted??? no retests on fan other than monthly checks, we'll see what happens with new shaft and housing.
very cold and more snow today.