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Pulley Problem

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Michael Oritt

Michael Oritt

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Yesterday my 100 began making an unusual noise and when I opened the hood I saw that the water pump pulley/cooling fan was wobbling and it was obvious source of the noise. On removing the pump today I found that the pulley was loose on the water pump shaft.


While the Moss parts diagram shows that there is supposed to be a key (part #55). presumably to engage the pulley, there is no keyway on either the shaft nor the pulley and of course no key--Instead there is a raised section on the shaft which is apparently supposed to engage the pulley (see photo). I also noticed that there is a bit of material missing from the inner shoulder of the pulley (see photo), perhaps damaged by the pulley's having wobbled.


I am concerned that the parts I have do not seem proper and am hesitant to reassemble everything merely relying upon friction and a press fit. Has anyone had a similar experience and/or any suggestions?
 

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My guess is that "raised section on the shaft" is the remains of the key. I would also guess that the shaft is probably worn down and the hole in the pulley is now too large. I would be looking at a new pump and pully.
 
Get a new pump and pulley as it looks like a Key shear?

Do not know why a key would shear However, the groove should still be in the pulley and can be be cleaned out.But the pulley is broken.
 
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1st pic shows clear break. Better get new.
 
Michael, how about a pic of the front of the pulley?

I'm sure if you took a small pick and probed around, you would find the remains of the keyway in the pulley. It's probably packed full of powdered iron at this point.
 
Yep new pump and pulley and that bump on the shaft is the remains of the key.
 
The last time I had the pulley off was probably 10-12 years ago when I fit a six-bladed flex fan and I do have a clear recollection of there having been a key and keyway, etc. New water pumps are apparently available but replacing the pulley may be a problem. Any suggestions?
 
Austin Healey Spares lists the pulley, pt# CHT124A. $62.17

BTW, the key way is halfway between two of the bolts. This is per the pulley on my spare motor project.
 
Thanks Craig.

BTW I am very thankful that the car gave me fair warning and the pulley/hub did not destruct, sending a fan blade through the shroud or radiatior as has happened to others.
 
Michael, I'm curious to know what you had in place as far as washers are concerned. I noticed something a bit unusual when I removed the nut and washers from mine. Typically, when a pulley is installed on a shaft, it extends slightly past the end of the shaft. This makes it easy to clamp it in place with normal washers and fasteners. In the case of our waterpumps, the shaft actually stands a little proud of the face of the pulley. This in turn requires a special washer that indexes on the shaft, not the threads, at its inside diameter. It is followed by a normal lock washer and then the nut. The nut seems to be rather large across the flats considering the diameter of the threads. The nut is also fairly thin ~ 1/4". I am concerned that the use of the nylock nut shown in your photo may have required the elimination of the stock lock washer and maybe even the special flat washer. Without that flat washer, the pulley would have never been properly clamped in place.

I will try to take some pics tomorrow after work to illustrate this.
 
Craig--

You were correct and what I took as the raised section on the shaft is in fact what little remains of the key. I cannot dislodge it from the keyway of the WP as there is hardly any edge showing and what is there has been pretty well rounded off.

As to your concern about the nut, etc. the unthreaded portion of the shaft does not appear to stand proud of the pulley. I remember having purchased this pulley used from someone and perhaps its previous owner had turned it down to clean up the threads and in doing so shortened the shoulder, but in any case the nylock nut and a normal washer--plus of course the key--appears to have held it in place for the last 10 or so years and 40,000 or so miles. I will attribute this failure to normal wear and tear and am thankful the pulley did not come to pieces and send parts of itself and/or the fan into the radiator, shroud, etc.

On a related note the six-bladed metal flex fan that I bought from BCS has the same amount of mileage on it as did the pulley. Does anyone have any experience with or an opinion on its life expectancy? All of the rivets (four per blade) are intact and the blades themselves are not nicked, bent, etc. etc.
 
Michael, I have had the same fan for about 10 years but only about 2,000 miles. I think your 40,000 miles indicates an indefinite life for this well made fan as long as your transmission strut keeps the engine from moving forward and having the fan hit the radiator.
 
TimK said:
Michael, I have had the same fan for about 10 years but only about 2,000 miles. I think your 40,000 miles indicates an indefinite life for this well made fan as long as your transmission strut keeps the engine from moving forward and having the fan hit the radiator.
Click to expand...

Tim--

Good to know and since I have a Toyota transmission I do not have the strut!
 
I also have a BCS Stainless fan. It seems bullet proof as long as you look at it once in a while for any defects. 6K miles and mine looks new. FWIW I recently bought a new water pump to have as a spare from Brit. Parts NW and they have one with the correct zerk fitting and heater water connection. I think some have found that these have not always been available for the BN1/2.
 
Jon--

I just ordered a WP from British Parts NW--it is NOT a County part so that's a good thing. I was also fortunate to locate a pulley so it looks like I will be good to go.
 
Michael Oritt said:
Tim--

Good to know and since I have a Toyota transmission I do not have the strut!
Click to expand...
Well, then I guess you have to keep your motor and trans mounts in good condition :smile:
 
It has taken me all this time to make the repair but I wrapped everything up this afternoon. I had to replace both the water pump and pulley and while at it I sent the alternator out for overhaul, etc.

I did this job without removing the radiator and the most difficult part was getting the four bolts that hold the fan to the water pump back into place. The blades of the Nock flex-fan are fairly wide and rather unforgiving on the hands/wrists--this took a couple of hours but in any case everything is buttoned up and back in place.

Unfortunately we had a fresh snow yesterday so it will be a while till the roads are salt-free.
 
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Per both Tim K and Steppenwolf: "Get your motor running" Doug
 
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