Motor fan disaster

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Model T Ford Forum: Forum 2015: Motor fan disaster
Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Friday, September 18, 2015 - 10:26 pm:

This is the second time that my fan shaft has come loose, moved forward, and almost ruined a very expensive brass radiator. (it did ding the lower tank - but in a spot easy to fix)

I must be doing something wrong. The fan shaft was screwed into the bracket tightly. The grease cup (which i think acts as a locknut) was also well torqued down on the end of the fanshaft. I happened to check everything before the ride on which the fan shaft came loose and still disaster almost happened.

It's NOT gonna happen again! But how to ensure it doesn't ????

I'm thinking of drilling the shaft and grease cup nut for a cotter key ? Locktite ? Weld the damn thing ??!

Anyone else faced this problem? Suggestions ?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Georgetown TX on Friday, September 18, 2015 - 10:41 pm:

Cotter pin.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Friday, September 18, 2015 - 11:01 pm:

Royce's idea sounds good but don't go over board on the hole or grease will just come out. Could the threads in all the parts be just worn out? Or are you trying to tighten the belt too much? It needs just enough to turn the fan and not much more.
The direction the fan turns it should be trying to tighten the bolt in the bracket not unscrew it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les VonNordheim on Friday, September 18, 2015 - 11:35 pm:

I use lock wire going thru the cotter pin hole and then wrapped around the adjustment bolt. That way, it can not come loose even a little bit.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Friday, September 18, 2015 - 11:50 pm:

He is talking about the fan hub shaft not the bolt that mounts it to the front cover.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Bennett - Australia on Saturday, September 19, 2015 - 07:47 am:

Bud's fan shaft does not have a split pin and nut to lock it into the support arm. The greaser with the internal thread acts as the locknut and these being pressed metal, are not as robust as a normal nut. When I fit those assemblies, I use a crescent wrench, end on, so that the jaws can engage the flats on the head of the shaft, and turn this with a second wrench to tighten the shaft in the support arm. I use loctite on the threads.

This way the greaser/locknut has little work to do. The only way to be more positive would be to then drill through the greaser and shaft and fit a split pin then.

Hope this helps.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Saturday, September 19, 2015 - 08:47 am:

Yes, it was the actual fan shaft that loosened and moved forward.

Mark is right, theoretically the direction of the belt movement should tighten the fan shaft not loosen it ..... and yet it did loosen (unscrew). Fan belt tension was good as I could move the fan by hand without too much effort.

The shaft itself is in good condition with near perfect threads. Can't comment on the threads on the grease cup nut as it was lost, but I do remember torquing them well when I put the grease cup on.

I guess the most reasonable fix is to drill both the grease cup nut and fan shaft for a small cotter pin after the grease cup is put on and snugged up.

A cotter pin will restrict the flow of grease through the small diameter fan shaft grease channel and will probably leak grease at the cotter pin hole, but I guess its the most practical answer. I have to be positive that this doesn't happen again.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David L Corman on Saturday, September 19, 2015 - 09:18 am:

If the fan is out of balance,vibration will result with a tendency to loosen it up.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Saturday, September 19, 2015 - 09:43 am:

I'll check that David, thanks for the tip.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith on Saturday, September 19, 2015 - 10:17 am:

I would check the threads in the bracket, and the shaft too. The grease cup is sufficient to hold everything tight.


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