Moss Europe - SU Pump Diaphragm

[geoberni]

Just a bit of a random discussion point.
My farcebook feed came up with an advert from Moss Europe, advertising a SU Pump Diaphragm, no doubt because Meta know I had been engaging in discussion here about SU Pump overhaul

So the Moss website offers a single Diaphragm kit for all pumps, between 1936 - 1980, with no mention of the pre-post 1985 difference that SU makes a deal of
https://www.moss-europe.co.uk/en-gb/dia ... mp-wzx1710

From the image it's a post 1985 diaphragm, which has a locating ring for the spring to sit on. SU speak of the Coil housing having the change of Earth Screw from 2BA to 4 BA, but so far I see no other difference to the Coil Housing. The presence of the spring prevents this difference in the locating ring on the diaphragm having any contact with the inside of the Coil housing....
All rather curious...

Thoughts anyone??

diaphragm.JPG (57.73 KiB) Viewed 3392 times

Edit to add:

I do have a small selection (4 or 5) of pumps up the garage, that I've brought from ebay which I have yet to disassemble. Of course ebay sellers rarely have a clue what they're selling in this regard, usually quoting the bottom housing part number as that of the pump...
Some may turn out to be HP rather than LP, since they have lost their metal tags, so perhaps I may yet establish a further difference around the 1985 Coils, though that still doesn't explain the Moss advert....

[svenedin]

I recently rebuilt a pre-1985 and a post-1985 pump with respective rebuild kits. Unfortunately, I didn't pay attention as to why the diaphragm is different so it is also a mystery to me. I am not quite bored enough to take the pumps apart to try to find out why there is this difference!

Stephen