Elektra Microcasa a Leva -- piston seal oddity

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rpavlis
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Postby rpavlis » Oct 11, 2017, 2:29 pm

This morning it was past time to service my Micro Casa a Leva group. I disassembled the group like I have done many times before, and then I cleaned everything very very carefully. After applying the normal silicone grease, I put the piston back into the group and fastened down the two Allen screws that hold the piston and lever assembly in place.

I turned on the machine and let it warm up. When I raised the handle to flush the group a bit, water came pouring out the air exit hole in the back of the group. This was very strange, because the seals seemed in very good condition when I had examined them. Strangely, the water leakage stopped. I let the machine stay "up to pressure" for about half an hour, and no more water leaked. I disassembled the group and reassembled it. I powered up the machine, and there was no water leaking past the piston at all this time. The question is, why did it leak after the first disassembly and reassembly?

Perhaps I somehow got something into the grease that was stuck against the seals? The cylinder wall was ideal. I have a towel that can be pulled through the group bore to clean it. I had cleaned it this way.

Have others had anything like this occur?

caeffe
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Joined: October 10th, 2007

Postby caeffe » Oct 12, 2017, 2:07 pm

I've had this happen before
Usually happens if I haven't used the Leva for an extended period, in the order of weeks/months. I also have an NS Oscar which is my daily driver. I typically only use the Leva on weekends at the most

If i haven't used the Leva for months, it usually will leak through the exit hole as you described. Eventually after a couple of cycles and flushing of water through the grouphead, the water coming up lessens till eventually it will no longer occur.

My SWAG: (sudden wild a.. guess) is that the materials eventually come up to temperature and the seals and metals swell up. As an aviation buff, this is somewhat reminiscent of how the SR-71 blackbird behaves on initial takeoff (an internet search should provide details on this); fuel leaks so much that a tanker is reqd to top off before it goes on its merry way.

Maybe other folks here can confirm with a more scientific / physics explanation but since my seals are relatively new and it eventually stops, I'm not too worried about it. I consider this a "feature" of the leva :lol:
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bettysnephew
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Postby bettysnephew » Oct 12, 2017, 7:41 pm

Sometimes softer seals will "twist" during assembly into the cylinder. I have seen this happen in the industrial world. Sometimes a couple of strokes of the piston will roll the lips of the seal back into proper position. This sounds like a similar situation.
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bill
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Postby bill » Oct 12, 2017, 10:39 pm

caeffe wrote:My SWAG: (sudden wild a.. guess) is that the materials eventually come up to temperature and the seals and metals swell up. As an aviation buff, this is somewhat reminiscent of how the SR-71 blackbird behaves on initial takeoff (an internet search should provide details on this); fuel leaks so much that a tanker is reqd to top off before it goes on its merry way.

My SWAG (scientific wild a.. guess) is that the seals got deformed when the piston was inserted in the cylinder, then corrected themselves when the piston was moved up and down a few times. I seem to remember this happening to me once.
Bill
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caeffe
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Joined: October 10th, 2007

Postby caeffe » Oct 13, 2017, 2:00 pm

bill wrote:My SWAG (scientific wild a.. guess) is that the seals got deformed when the piston was inserted in the cylinder, then corrected themselves when the piston was moved up and down a few times. I seem to remember this happening to me once.


A possibility and probable, I concur

This would mean that the seal has corrected itself after warming up and that it shouldn't occur again the next I turn it on.
In my instances (this happens often to me since I store/put away the Leva occasionally), it doesn't correct until I use the machine after 2-3 days. Initial turn on each time, I would get leakage through the exit hole. Eventually by the 2nd or 3rd day of use the leakage is no longer there.
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