Henderson/Whale bilge pump, problem

[Twister_Ken]

The boat is ashore. I pumped the bilge a couple of weeks back, just to see if there was anything there. There wasn't, but while pumping enthusiastically, there was a metallic click, and the pump handle suddenly felt as if it wasn't connected to anything.

I took the pump apart this weekend and found that the diaphragm is sandwiched between two metal plates which are connected to the pump actuator (that which is wiggled about by the handle). The outer of these two is held in place by a plastic nut, which screws a long way onto the actuator. The nut had unscrewed itself, allowing one plate to fall off, and stopping the diaphragm working. Fortunately, an easy fix, but how to stop it happening again? It's a plastic nut onto a plastic spindle, so I suspect loctite or similar won't work. I'm reluctant to drill through the spindle to put a pin through, in case a create a weak point which migh fracture. Any suggstions?

BTW, if you have a similar pump (Henderson Mk V, now marketed as the Whale Mk V universal) i'd suggest you remove teh inspection plate form time to time and make sure that the nut is firmly in place. It could be embarrassing if it fell apart when you were seiously in need of it.

Diag here:
http://www.whalepumps.com/popup.php?n=ex...;bgcolor=ffffff

The nut in question is the one nearest the artist, mor or less in line with the word 'diaphragm'.

 

[michael_w]

Locknut? Or if you haven't got the space how about a locking washer?

 

[Fr J Hackett]

Can you make up a soft metal locking tab say out of copper? I have two of them and can remember but cant visualise the set up, will check mine though thanks for the tip.

 

[Scotty_Tradewind]

Hi Ken,
Michael beat me to it. Locknut, or even Locktite on the thread maybe? Needs to be a good reult as it could be much needed in a hurry as was my situation when the stern gland gave way this last summer!

 

[santeana]

A couple of turns of PTFE tape on the plastic spindle may do the trick.

 

[Twister_Ken]

Locknut - why didn't I think of that? Where to get plastic nuts - any suggestions?

PTFE suggestion made me wonder - how about a cable tie around the spindle?

 

[PuffTheMagicDragon]

Another possibility is a dab of rubber based contact adhesive, such as is used for Formica. I would tighten the nut and then dab some of the goo onto the spindle behind the nut. It should prevent the nut from unscrewing itself, yet can still be removed by applying some paraffin / kerosene to it.

 

[PembrokeshirePromise]

Strange, had just the same happened to mine - except in my case the plastic nut had a hairline crack in it - so every time force was applied off it popped.

Fortunately had an old pump I could raid for spares - as I've no idea where I would have got that nut from !

 

[Scotty_Tradewind]

How large is the thread? Could it be drilled so that some s/s seizing wire be put through to prevent the nut from coming off?

 

[santeana]

Maybe a bit off the wall but would a nyloc nut be effective? Maybe use it as a locknut to give belt and braces.

 

[Twister_Ken]

AFAIK Nylok nuts are mostly metal. I'd be reluctant to screw a metal nut onto a plastic thread, for fear of damaging the plastic thread.

 

[VicS]

[ QUOTE ]
I'd be reluctant to screw a metal nut onto a plastic thread, for fear of damaging the plastic thread

[/ QUOTE ] Especially a Nyloc nut! .

 

[vyv_cox]

I can't really see why Loctite won't work. Adhesion to plastic will inevitably be less good than to metal but I suspect it will be sufficient. Nothing to be lost by giving it a try.

 

[michael_w]

Coo! Is this my first Lakesailoring?? And from such an august forumite as Twister_Ken.

/forums/images/graemlins/cool.gif

 

[saltwater_gypsy]

Where to get plastic nuts - any suggestions?

go to: http://www.gtc-direct.com/contact.asp

 

[Twister_Ken]

GTC- Direct.

Nope

 

[Topcat47]

A dab of Fernox LSX is what you need. It sets after a fashion, but never hard, you can rub it off with your finger, even when set and has a low shear modulus for when you want to take the nut off. I do it whenever I have to change any parts on the pump and it's not let me down in fifteen years.

 

[maxi77]

Agree no plastic nuts, but what a painful site. Doubt if I have the patience to buy from them.