Leaking WHALE Mk 5 pump

[bebox]

Appreciate help: diaphragm looks soft not hardened and aged, not torn, central nut is well tightened, yet the pump leaks. Tried silicone on fitting surfaces around, no joy. Any good tips? Many thanks!

[peghall]

Two most likely possibilities: a pinhole leak in the diaphragm that's too small to see yet (more likely if the pump is close to 5 years old or older)...or screws through rubber flange/gasket that have been overtightened. Over-tightening causes the gasket "pucker" which creates a leak around the screw. Further tightening just makes it worse.


--Peggie

[bebox]

I have certainly overtightened the bolts in my despair and the diaphragm may well be over 5 years old - so both explanations may be true. I shall change the diaphragm and tighten less. Many thanks for the speedy response!

[peghall]

Tighten bolts equally one at a time just barely snug...if it leaks, just a quarter turn on each one--no more...repeat till the leaking stops.


Oh...btw...this also applies to toilet joker valves and all other screws through rubbers gaskets.



--Peggie

[Training Wheels]

Originally Posted by bebox

I have certainly overtightened the bolts in my despair and the diaphragm may well be over 5 years old - so both explanations may be true. I shall change the diaphragm and tighten less. Many thanks for the speedy response!

We live aboard, and our pump diaphragm lasts a year. It’s part of my regular maintenance program now to change it every year during the off-season, so that I’m good for the cruising season.

[Reefmagnet]

Uneven torque on the screws retaining the diaphragm and holding the casing together can cause the pump to leak, even with a new diaphragm installed. It doesn't seem to take them being out of wack too much to result in an annoying dripping leak, either. You have to treat the tightening of these screws as you would the head on an engine.

[bebox]

Many thanks to all! Much appreciated...