Water pump shaft thread at fan

[Hoogah]

I've been trying unsuccessfully to remove my fan so that I can replace it with the new 2-blade aluminium one that I bought. I tried reversing the castellated nut and striking it several times, but only succeeded in splitting the nut!

Have since found a thread here full of similar experiences and it seems that the solution is to buy the tool, which is what I'm now going to do.

However, I am concerned that the thread on my water pump shaft needs cleaning up before I put the new castellated nut on (. . . assuming I get the old fan off!! )

I don't have a tap and die set, so I'll need to borrow one or find someone to do this, but is there a description of the thread that will help me to locate and use the correct die? (e.g. pitch, spacing etc?).

And if I get that, does the same description apply to all threads used on the car?

My car consists of an AR phaeton body sitting on '28-'29 running gear.

[colin1928]

Hoogah the common threads on A models are UNC and UNF as well as other odd threads I use a thread file to clean water pump threads in fact my thread file is 1 of the most used tool in my tool kit
Colin

[Tom Wesenberg]

I bought the knocker tool from the parts suppliers for a few dollars. Hold the fan hub in my left hand and give the tool a good smack with a hammer, and the fan should pop loose. I've seen too many damaged threads when the right tool isn't used for the job.

[Hoogah]

Originally Posted by colin1928

Hoogah the common threads on A models are UNC and UNF as well as other odd threads I use a thread file to clean water pump threads in fact my thread file is 1 of the most used tool in my tool kit
Colin

Yeah, never had one but maybe now's the time! Thanks for this advice Colin.

[RonC]

Now is the time to replace your pump with a quality leakless if you don't already have one

[Kurt in NJ]

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For a stock water pump the parts book lists 34031s as 7/16 -20

[Tom Wesenberg]

I forgot to mention the other method I have used. You simply screw a nut half way onto the shaft, then screw a short bolt into the nut, and smack that bolt with a hammer. This way the force is against the shaft end, and not against the threads.

[Keith True]

An old head nut and stud makes a good knock-off tool.Screw the nut halfway onto the pump,screw the head stud in that,until it bottoms out hard,and belt it with a hammer while holding the pulley in your hand.The pump needs to be off to do this,if you try to do it with the pump still mounted you will just be pounding the head.The pump shaft will be acting like a punch on the wear pad on the inside of the head.

[Hoogah]

Originally Posted by Tom Wesenberg

I forgot to mention the other method I have used. You simply screw a nut half way onto the shaft, then screw a short bolt into the nut, and smack that bolt with a hammer. This way the force is against the shaft end, and not against the threads.

Originally Posted by Keith True

An old head nut and stud makes a good knock-off tool.Screw the nut halfway onto the pump,screw the head stud in that,until it bottoms out hard,and belt it with a hammer while holding the pulley in your hand.The pump needs to be off to do this,if you try to do it with the pump still mounted you will just be pounding the head.The pump shaft will be acting like a punch on the wear pad on the inside of the head.

Thanks Tom and Keith for the option.

Originally Posted by colin1928

Hoogah the common threads on A models are UNC and UNF as well as other odd threads I use a thread file to clean water pump threads in fact my thread file is 1 of the most used tool in my tool kit
Colin

Originally Posted by Kurt in NJ

For a stock water pump the parts book lists 34031s as 7/16 -20

If I go down the thread file path for cleaning up the thread, does 7/16-20 denote a 7/16 UNF thread with 20 TPI?

AND... What range of TPI should I include in any file that I purchase? (These files appear to handle a range of TPI, but at about $45 ea, I don't want to have to buy another file down the track if I can get away with buying the right one now.)

[tbirdtbird]

thread files are double ended and should have the most common 8 pitches available: 4 per each end of the file

UNF (or SAE) (fine thread) in this case would be what you said at 7/16-20 with 20 TPI. I am sure the files out there would have this pitch.

never hurts to own a set of taps/dies

[colin1928]

Any imperial (UNC/UNF) thread file will have the correct TPI
you will wonder how you lived without it