Does a Henderson Mark V service kit fit the older Mark III

[eebygum]

I’m in NW Scotland and just had to rebuild the toilet Henderson Mark III pump flapper valves for the Lavac toilet from my spare pump…. And now looking to get a replacement kit sent to Orkney to rebuild the spare pump !

I cannot find any online replacement service kit for the Henderson Mark III, only the Mark V are sold.

Does anybody know a supplier of a Mark III service kit or can confirm the diaphragm and flapper valves from the Mark V service kit fit ?

 

[Topcat47]

No, The valves are different. I converted a Mk 4 to Mk5 by replacing the plastic cover because the valves are different. The basic body had the same PCD and screw threads but that was about four years ago. I doubt that the Mk3 would be even close.

 

[earlybird]

I doubt if mk. 3 spares still exist. From strained memory, I made mk.3 valves from rubber sheet about 3mm thick. The mk.5 inlet valve is different from the mk.3 and will not suit, but I think that the outlet valves maybe similar. Again, vague memory, the mk. 3 diaphragm is similar outline but is flat, lacking the corrugation of the mk.5.
I'd be thinking of replacing the pump, any spares soon mount up in cost.

 

[eebygum]

I doubt if mk. 3 spares still exist. From strained memory, I made mk.3 valves from rubber sheet about 3mm thick. The mk.5 inlet valve is different from the mk.3 and will not suit, but I think that the outlet valves maybe similar. Again, vague memory, the mk. 3 diaphragm is similar outline but is flat, lacking the corrugation of the mk.5.
I'd be thinking of replacing the pump, any spares soon mount up in cost.

Yes the Mk 3 inlet and outlet valve is 3mm flat rubber. The Lavac toilet pump was perfectly fine other than the flap valve that I had to replace from my spare pump.

I may have a go making some up if no service kit is available…. I did this a few years ago on a Henderson pump using a cut out from a rubber car mat… unless anybody can recommend a better substitute ?

 

[earlybird]

I may have a go making some up if no service kit is available…. I did this a few years ago on a Henderson pump using a cut out from a rubber car mat… unless anybody can recommend a better substitute ?

Ebay is a good source of small pieces of sheet rubber at low cost:- neoprene, nitrile, viton, silicone,; take your pick.

 

[andsarkit]

If the flap valves don't seal you can turn them over on the Mk 3. No need to remove the screws, just pull them off and push them back over the screw heads. I will check when I'm next on the boat as I might have some spares.