Chimp Mk 1 Bilge pump diaphragm

richardabeattie

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Must I really pay £61 for a repair kit containing little more than the hexagonal rubber diaphragm that I need? Round diaphragms for Mk 2 are available on ebay at under £20 but apparently not for Mk 1.
 
New pumps are indeed cheaper than the repair kit but don't begin to fit the same hole in the side of the cockpit. I'd have to fill in a large round hole and then cut another one into the repair. Not for me!
 
Must I really pay £61 for a repair kit containing little more than the hexagonal rubber diaphragm that I need? Round diaphragms for Mk 2 are available on ebay at under £20 but apparently not for Mk 1.

Hi Richard,
I have the same problem which has been solved by purchasing neoprene sheet on Ebay. The hardest bit is drilling the 6 screw holes in the right place.
I clamped the sheet between 2 pieces of ply and drilled through the holes of the "cover plate" to get the alignment right.
It's a cheap solution but I have noticed that in time the rubber cracks on the outer surface , I assume due to UV damage. Perhaps nitrile rubber would be better?
 
The diaphragm is an octagon with 8 screw holes and a large central hole. Don't see any easy way of making one as the slightest irregularity especially in the central hole would be where the next tear would start. I'm told that these diaphragms are only available as part of the £61 kit. It's a good job all we yachties are rich.
 
Admittedly I haven't seen or handled one but to me that looks like a very easy thing to make accurately using hole punches and a sharp scalpel if (as it appears) it is simply flat sheet without any re-inforcement or flex rings moulded in. Neoprene sheet on Ebay for under a tenner available in many thicknesses, or convert to nitrile sheet as suggested. But then again I do make myself gaskets like in the second picture.
 

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