Water Pump Pulley

[Eric Aldcroft]

I took my Javelin out today for a planned 150 mile or so round trip. I had to terminate the trip early due to a slipping water pump pulley. On investigation we found that the Woodruff key had disappeared! We effected a quick fix using a self tapping screw to jam the pulley in place and that got us back home -- about 40 miles. Looking at my spare water pump parts, I find that the hub on my spare pulley is cracked around the key-way. I think I have a usable spare shaft though. Has anyone any suggestions for using an alternative pulley (e.g. a steel one), or any alternative mounting arrangement?

[Mike Allfrey]

Dear Eric,

Oh Dear! (That is a part of the Jowett mechanic's vocabulary, usually prefixed with Oh Gosh!) The water pump pulley must have a good quality Woodruff key to drive the pump. All too often, during assembly, the key is loose in the shaft and, while the pulley is pushed over it, it can dislodge and fall into that convenient crevis on the floor - most times un-noticed by the unwary. This is particularly so as we get older and deafer.

I use a small spot of Loctite 518 Mastergasket under the key and allow it to cure while lightly clamped with vise-grips. Using the Loctite means that the key can be removed later.

The pulley should have a good straight keyway and should be a reasonable fit on the shaft. The pulley should be retained by a thick 3/8" plain washer and be secured by a good quality Nyloc nut. If in doubt, place a smear of Loctite 518 Mastergasket on the shaft thread to hold the nut after tightening. The nut must be tight, it also locks the inner race of the bearing to the shaft, or the pulley and key will fret. I have seen a case of the key fretting the pulley to the extent that, eventually, the key was lying on its side! Inside the bore in the pulley.

Good luck,

Mike Allfrey - E0 SA 42R.

[Forumadmin]

A similar fate occurred to Duncan Laing's pump on the way to JAW. Replacement pump was fitted in hours, thanks to the helpful Jowett network.

[Eric Aldcroft]

Thanks for the comments Mike & Keith. Just to complete the saga, I am now back on the road. I attempted to get the pulley with the cracked key-way repaired, but when the welder discovered that it was not made of aluminium, he gave up after leaving a small blob inside the bore and a larger one on the periphery of the hub. However, I decided to run with it after re-drilling the hub and deepening the key-way. The latter being necessary, because the Woodruff keys I found required a 1/8" deep key-way. It went together well and the locktite was applied. I have my fingers crossed.

I would still like to replace the pulley though, and neither JCC Spares nor Bill Lock can supply me with one at present. If anyone has one or knows of a source, I'd really like to hear from them.

Cheers,

Eric Aldcroft

[Bryan Walker]

Hi Eric,
Jowett Spares (NZ) have new pulleys (made in Australia).
I think they are about $95nz dollars,
If ordering there are 2 types, flat or extended Boss.

Bryan

[Eric Aldcroft]

Just to comlete this mini saga. I purchased a new pulley (complete with Woodruff key and nyloc nut) from Jowett Parts NZ. I received it today, and it is now installed. I will now feel more secure and will be watching carefully for any nut loosening!

[David Morris]

Hi there,

Having seen recently what happens when the nuts loosen and the pulley assembly 'frets' in use, Chris Cole and I wanted to fit replacement Nyloc nuts to our pulleys and had some difficulty in discovering the thread size that would fit the pump shaft. It appears that M10 (Fine) with a 1.25mm pitch are a reasonable fit. My local nut and bolt suppliers had plain nuts in stock but not Nylocs. However, these are available from Namrick (01273-736963) and I am sure there are other suppliers.

Bit of a mystery as to why Jowetts used a metric size, Chris suggests it might have been due to the bearing size used in the pump? Who knows, it's a Jowett after all! Expect the unexpected!

All the best,

David