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Old 04-24-2026, 11:24 AM   #1
Himi52
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Default Model A water pump pulley alignment

Hi,
I purchased a new water pump with a two blade fan. My old ware pump was leaking and I thought I should replace it.
After installing the pump, the pulley does not line up with the generator. Is there something I might have done to make the misalignment?
Thanks for your ideas.
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Old 04-24-2026, 11:46 AM   #2
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Default Re: Model A water pump pulley alignment

have you got the pully key lined up on the shaft properly? it looks to me like the pully is not all the way seated on the shaft. is it on far enough for the cotter pin?
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Old 04-24-2026, 11:50 AM   #3
Oldgearz
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Default Re: Model A water pump pulley alignment

Now that's weird. I have an alternator so I don't know the generator set-up. I guess there's no adjustment on the gen, or you would have done that. Looks like you're 3/16" to 1/4" off. Maybe shim the generator pulley with a washer or two?
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Old 04-24-2026, 11:59 AM   #4
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Default Re: Model A water pump pulley alignment

here is how it is supposed to look. check that key to make sure it is lined up properly.
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Old 04-24-2026, 12:38 PM   #5
Himi52
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Default Re: Model A water pump pulley alignment

I thought I had the key lined up. But maybe I missed it. Thanks for the picture for my reference.
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Old 04-24-2026, 01:10 PM   #6
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Default Re: Model A water pump pulley alignment

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If you tighten the nut up with the key out of place you will crack an aluminum fan.Pull the fan,remove the key,and slide the fan back on the shaft without the key.Spin the fan around,while holding the shaft still.You'll be able to tell when the fan is seated on the shaft.Then mark the water pump housing at the rear of the fan pulley.That is how far the fan needs to slide on with the key installed.Not the first time I've seen it happen,and I've seen two cracked new fans from guys not paying attention while installing the fan blade.
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Old 04-24-2026, 01:13 PM   #7
Kurt in NJ
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Default Re: Model A water pump pulley alignment

Is it possible that the timing cover is for a 33-34 engine?
Does the crankshaft pulley match the generator position or the fan position for the belt
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Old 04-24-2026, 10:14 PM   #8
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Default Re: Model A water pump pulley alignment

I will check tomorrow. Thanks
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Old 04-25-2026, 07:25 AM   #9
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Default Re: Model A water pump pulley alignment

Quote:
Originally Posted by Kurt in NJ View Post
Is it possible that the timing cover is for a 33-34 engine?
Does the crankshaft pulley match the generator position or the fan position for the belt
Everything you need to know about timing covers courtesy of Vince Falter.

https://www.fordgarage.com/pages/timingcovers.htm

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Old 04-26-2026, 06:09 PM   #10
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Default Re: Model A water pump pulley alignment

Hi,
I took the water pump off the car. I have been trying to get the fan separated from the pump. I must have really messed up in the installation. I have been using the fan knock off tool to no avail. I ave been taking the water pump with the installed knock off nut and hitting the nut on the concrete. It hasn’t moved. Any suggestions?
Thanks
Thanks for your help.
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Old 04-26-2026, 06:44 PM   #11
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Default Re: Model A water pump pulley alignment

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Originally Posted by Himi52 View Post
Hi,
I took the water pump off the car. I have been trying to get the fan separated from the pump. I must have really messed up in the installation. I have been using the fan knock off tool to no avail. I ave been taking the water pump with the installed knock off nut and hitting the nut on the concrete. It hasn’t moved. Any suggestions?
Thanks
Thanks for your help.
Take an old head stud thread nut partially on an then attach to water pump shaft hold fan and hit with a solid hammer close to ground so you don't drop pump or fan it will come off!
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Old 04-26-2026, 08:13 PM   #12
Keith True
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Default Re: Model A water pump pulley alignment

I don't understand what you mean by,hitting the nut on the concrete.I have no idea how you could hit the nut on the concrete.You screw on the knock off tool,either a store bought one,or the one Gary shows,(they do the same thing) then smack it hard straight on the end with a hammer,while suspending it in your hand by the fan blade.Don't poot around with it,hit it like it's going to bite you.
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Old 04-26-2026, 08:29 PM   #13
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Default Re: Model A water pump pulley alignment

I stupidly put the fan and pump between the jaws of a vise. Hit the end of the shaft and broke a chunk out of the pulley. Use your hand to hold the fan blade!
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Old 04-27-2026, 07:48 AM   #14
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Default Re: Model A water pump pulley alignment

that fan is aluminum and it will heat up quicker than the shaft. so if you have an electric heat gun (harbor freight will have cheep ones.) (it should heat up quick and with the electric is should not get hot enough to hurt the fan) heat the fan up to expand it. hot.
this works on tapered shafts but am not sure the key will release.
i think that would be my first go to.

ps
a hair drier is not hot enough.

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one last suggestion.
panicking is never your friend.
i do some of my best problem solving at night lying in bed.
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Old 04-27-2026, 07:59 AM   #15
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Default Re: Model A water pump pulley alignment

At least half the problem with the aluminum fans is that the fan is ENTIRELY made of aluminum, including the pulley. Some of this is probably forced by strength: if you join with fasteners then its possible that the fasteners might fail. The same failure mode that the 40s and 50s "replacement fans" had (i.e. the two or four sheet metal blades held by rivets, or bolts and turning on a steel turned center.)

So today they pour/cast the fan in aluminum as a "unit." BUT - forgetting that you don't necessarily want to leave the tapered hole in "as cast" condition.

It should be machined out as a taper, to be done right. But many perhaps most are not.

And the as cast taper is not necessarily uniform or even concentric with the centerline of the hole. Reports of a "high spot" about mid-way along the taper, possibly done so the casting can be removed from the mold? And results in "circle contact" between the shaft taper and the pulley hole.

Vendors, including my friend Tam, advise that their best solution is to "strongarm" the attaching fan shaft nut - possibly even do it two or more times with operation between as the fan hub works in and "stretches" around the shaft taper.

Which makes for a struggle in fan removal as a "taper fit" becomes an "interference fit."

One wonders how the newer and expected more expensive "carbon fiber fan" will have as attachment?

I will give the aluminum fans credit: I've never heard of a failure once a fan is beyond the "infant bedding" stage of installation.

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Old 04-27-2026, 08:02 AM   #16
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Default Re: Model A water pump pulley alignment

sorry! one more thing. if you heat it up you will need welding gloves or something to wrap the blade with so you don't burn your hands when you go to hit it.

this is how we all learn. sometimes it gets $$$$$$

good luck.
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Old 04-30-2026, 10:22 AM   #17
Himi52
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Default Re: Model A water pump pulley alignment

I was able to remove the fan by using a small wheel puller with three arms. I took the key out and spun the fan and found some places that needed to be filed. I am going to try a dry fit to see if the pulleys are lined up. I am hoping that the taper in the fan is a correct match for the shaft. I will keep you posted.
Thanks
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Old 04-30-2026, 10:35 AM   #18
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Default Re: Model A water pump pulley alignment

Quote:
Originally Posted by Himi52 View Post
I was able to remove the fan by using a small wheel puller with three arms. I took the key out and spun the fan and found some places that needed to be filed. I am going to try a dry fit to see if the pulleys are lined up. I am hoping that the taper in the fan is a correct match for the shaft. I will keep you posted.
Thanks
awsum.

the fan should seat down like the pic i showed you.
it may stick even without the key if it does warm it up and it should fall off again.
once you are happy with the fit and the nut will go on far enough for the cotter pin (don't tighten it ) then pull it back apart and put the key in.
nice one.
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Old 05-01-2026, 03:16 AM   #19
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Default Re: Model A water pump pulley alignment

Quote:
Originally Posted by Himi52 View Post
I was able to remove the fan by using a small wheel puller with three arms. I took the key out and spun the fan and found some places that needed to be filed. I am going to try a dry fit to see if the pulleys are lined up. I am hoping that the taper in the fan is a correct match for the shaft. I will keep you posted.
Thanks
Himi - this is a common problem. I have found that on the last half dozen or so aluminum pulleys I’ve installed, the hub of the fan rubs on the nose of the water pump housing. I now turn down the noses of all water pump housings before I assemble them. The best way is to use a lathe, but you can do it with a hand grinder as well.

The dimension I have found to work well for the nose is 1.640”. See also https://www.fordbarn.com/forum/showt...ght=Water+pump for a similar discussion several months ago.
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Old 05-01-2026, 01:55 PM   #20
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Default Re: Model A water pump pulley alignment

i would not hit that with a grinder.

you could smeer some course valve lapping compound on that shaft and lap it down. i think that may work and it would result in a better fit.
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