Fan Hub movement, how much is acceptable?

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Model T Ford Forum: Forum 2015: Fan Hub movement, how much is acceptable?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Thursday, April 30, 2015 - 07:22 pm:

After reading another thread on a runaway fan blade I checked my blades and found there is some play in the hub.
The blades look fine but if I hold a fan tip I can move the hub in and out enough to hear a clunk although its only a couple of mm. Is there any risk of this failing or is it common?
Also I'm coming into Winter here plus the T never looks like running hot on a good day so I thought I might disconnect the fan until next summer leaving the Fan in place. Whats the best way to slip the belt off?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Thursday, April 30, 2015 - 07:34 pm:

Kevin
Your fan is mounted on a eccentric to the upper water neck?
Looseness; check the condition of the blades at the hub. How much is your radiator worth if you put a blade into it?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Thursday, April 30, 2015 - 07:46 pm:

Les I dont want to risk a Radiator hence my intention. The blades are firm it is just the hub itself slidding in/out a small amount.
I dont understand your first line so here is an old pic that might clarify


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Friday, May 01, 2015 - 12:31 am:

Kevin

A bit of movement is OK, means that the bushing is worn. IMO leave it alone for now.

That fan needs to be rebuilt to std. 26-27 style. Fan now has mis-mash of parts. The blade assembly is earlier, the fan shaft isn't the correct one for that eccentric fan bracket. If you try to loosen the nut under the eccentric lug, the fan shaft will just get more loose and perhaps wobble.

Review paragraph #1200 of the Service Manual. Then know that your bracket is the improved version with the long ended fan shaft with 2 flats to hold while turning the nut to tighten the eccentric collar. That improved version is subject to a Service Bulletin.

Attached are photos of the correct bracket, shaft and blade assembly your T should have.





Note the 'protruding' shaft with the 2 flats above the lock nut. Those are held in place when loosening the lock nut, otherwise the fan shaft will become loose.




Square edge fan blade is correct





If you are intent on removing the fan belt, then loosen that hex lock nut to relieve the pressure on the eccentric collar with the lug, (do use penetrating oil as the eccentric collar can be stuck from rust, the upper side of the bracket has a tiny oil hole to lube that collar); then rotate the plate by a wrench on the lug, until the fan assembly dropped down and the tension on the belt is relieved. Then slip the lower end of the belt off the crankshaft pulley, and lace the belt up and around the fan blades till its off.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick on Friday, May 01, 2015 - 01:33 am:

I made this drawing several years ago of the fan assembly on my '26 coupe when I disassembled it to install a set of new fan shaft bushings. While it is not exactly proportional, it does give you an idea of what is inside. The pulley is convex so that the fan belt remains centered on the pulley between the flanges as the fan automatically climbs to the highest or tightest point on the pulley. Jim Patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Friday, May 01, 2015 - 03:52 am:

Ok I have taken my fan completely off. I havent disected it yet but what exactly wears that I need to replace?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Friday, May 01, 2015 - 04:24 am:

Also the adjuster is still attached and wont turn at all. I've sprayed with crc but could this fall out when travelling once its loose?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Friday, May 01, 2015 - 09:07 am:

Not sure how this relates to the "improved" fan. but on my 15 touring I had the nut on the end of the fan shaft come loose. Can't remember if I double nutted it or lockwashered it, but trust me you don't want that nut coming loose.

In my case the fan and shaft moved forward far enough to hit the fins on the back of the radiator. Fortunately it was on an old near worthless radiator and I caught it before it did any real damage - but it could have been a disaster with a good radiator.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Friday, May 01, 2015 - 10:34 am:

Kevin

The 'adjuster' you posted, assume you mean the collar in the bracket of the outlet. Yes, that can fall out. You need to remove it. Use lots of penetrating oil, but as its still vertical, gravity is draining away the penetrating oil. So you can try to use a block of wood, and hammer, and drive the collar out from the front, toward the block. That will free up the collar and it should push out of the bracket. Lots of time, dripping coolant (water) from the hose above will wet the area of that round collar inside the bracket and rust it fast.

As for the hex nut stuck on the end of the fan shaft, if you turn it, the shaft will just turn with the hex nut. So you have to remove the blade assembly from the pulley. Then you can 'hold' the flat faces of the fan shaft head, and that will fix the shaft while you un-thread the hex nut.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Tomaso - Milton,WA on Friday, May 01, 2015 - 11:57 am:

To add to Dan's advice: I have found examples of later style (as above) fan brackets that had an oil lubrication hole located near the 1:30 - 2:00 o'clock position, on the driver's side looking from the front. Whether that is factory or not, I cannot answer.

One might attempt to merely turn the adjuster one way or the other to possibly free it also.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Tomaso - Milton,WA on Friday, May 01, 2015 - 11:59 am:

There also doesn't appear to be the "2 flats" on either side of the fan shaft ?


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A Bartsch on Friday, May 01, 2015 - 12:47 pm:

Kevin:

The '26-'27 uses fan shaft # 3966C, as shown in J Patrick's sketch & Lang's catalogue:

https://www.modeltford.com/item/3966C.aspx

You are using what appears to be part # 3966B from an earlier year.

Respectfully, jb


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dewey, N. California on Friday, May 01, 2015 - 02:30 pm:

I would be very leery of beating or pressing on that adjuster while in the car. It is only supported on one side, and you are likely to break the housing. Take the housing off, and support it well when pressing on it.
I would probably put it back together with a light coating of anti-sieze so this doesn't easily happen again.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Friday, May 01, 2015 - 03:12 pm:

All good advice thanks guys. I think I might remove it from the car if it plays hard to remove.
So to address the slight inward/outward movement which is the reason I removed the hub do I need the following parts - replace the brass bush set (3974b), correct bolt (3966),Pulley gasket (3981)plis (3982) & (3983).

What is the expected life span of this system once renewed compared to the Langs "Fan Hub ball bearing Pulley" (3962BBN). As far as length life plus reliability between the two options?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Sunday, May 03, 2015 - 06:30 am:

I squirted the housing every few hours over the last 2 days and it finally come free tonight. I have removed and cleaned up and I think it was just the bolt not tight enough as when I done it up there is no end play. Might refit tomorrow and see how it looks once assembled.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick on Monday, May 04, 2015 - 12:37 am:

Model T's were driven much more when new, than they are now and your fan lasted this long, so, if kept oiled, it should last indefinitely, or a good 50 years, or more. The bushings are easy to replace (since I don't have a press, I pressed mine in with wood clamps) and should take up any end play you are experiencing with your shaft. Jim Patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Monday, May 04, 2015 - 07:14 am:

Thanks Jim, tonight I just refiited it. The bushes were fine and it was full of clean oil but I noticed there was no felt washer. I fitted a felt washer and it seems fine with no play so i will fill it with oil and see how it goes.
I see mine has the bolt without the square ends...are these bolts any longer than the older model bolt as it seems slightly short.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Monday, May 04, 2015 - 10:03 am:

Kevin

Yes. You should get a new shaft, the correct one with the flats on the end. That is important on how you can tighten up the hex lock nut. Otherwise the shaft will turn with the lock nut and make the fan shaft too tight and you will have a stuck fan or squealing bushings :-)



Just re-worked a '23 fan assembly and the bushings were fine, just had to replace the fan shaft with a better used one in my stash. This is the early shorter length fan shaft.

Here is correct later '26 fan shaft and how to tighten the hex lock nut after the eccentric has been rotated to gain proper fan belt tension.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Monday, May 04, 2015 - 10:15 am:

View of the two shafts, the 3966C ('26 and later) is the one with the flats, its also longer, in the threaded portion for this reason.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Monday, May 04, 2015 - 04:13 pm:

Ah ha that explains it as the nut only threads on about 3/4 of the nut. I spent ages on it last night trying to work out what I was doing wrong lol so I've drilled a hole thru the nut and fitted a split pin to hold. I will order the correct bolt.
Thanks heaps


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Friday, May 08, 2015 - 06:30 pm:

Update - Still running fine with no end play at all and no oil leaking out. Should see me through the winter.
The felt washer I used I had on hand from a selection of rear end washers I had ordered previous, exact fit!


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