I have a spectra water maker. I am trying to change end fittings on my cklarckpump. But I can't get I lose, the outer ring that holds the end fitting.
Should come off with a strap wrech. If not, put the edge of a piece of hardwood in the notch and give a few whacks to loosen.
Cylinder Disassembly (Do not disassemble the cylinder unless there is a problem) Hold the base of the S.S compression fittings and loosen the nuts to remove the J-tube. Loosen the base fitting first. Use the spanner or a strap wrench, oil filter wrench, or a nonmetal punch in the groove to loosen the aluminum cylinder ring then remove the ring and plastic end cap."
Looks like a cracked cap from over tightening. Where are you located?
I tried it all, it is not coming lose. I try heating it a litel, tips from spectra tech. But that did knot worked.
At this moment I put it all together and it works but it leaks. Just know we are at Maderia, and we are soon going to the Canaries, there we hope to find someone how can rebuild the and give the pump some service.
I've replaced customers clark pump cylinders but never the end cap only unless it was on a membrane housing.. Maybee Tellie could ship one out to you.
That end cap is toast and the ring has to come off or you'll have to replace the whole cylinder. This may sound brutal but get a large enough Monkey wrench. Preferably clamp the Clark pump in a vise. It will slightly scar the ring but the Monkey wrench will give you the best leverage. Do not apply great pressure to the wrench. If it does not come loose then apply pressure to the wrench and sharply whack the long end of the wrench with a hammer multiple times to shock the ring loose. If all this fails you can try to weld the crack by heating a screw driver with a torch and melting the crack to seal it. This is best performed with the SS fitting removed and may mean you'll need a tap to re-thread the end cap. I've never met a ring that wouldn't come loose but if you're truly the first you may need to just order a new cylinder kit and replace the whole thing.
I don't have a monkey wrench in that size, I don't think  that would work either, maybe if you are in a proper workshop.
I would try to weld it if we can't find some one who can do services to the pump when we are on Canaries island's.
I would not weld with it in place, you might damage other components. Maybe just try something like JB Weld on the crack for now.
Its a lot easier to work on a Clark pump on a work bench. Removing and getting on a bench will actually save you time and give you better leverage.
Will the ring on the opposite end turn?
Don't mean to be a smart azz, But righty tighty...lefty lucy?
I have not tried the opposite ring, that side is fine, and I will leave it that way.
Next step is to find a works shop hear in Funshal and try to get inside to work on it, if not here it bee Canaries in a week or so.