1377c - Was Leaking Down, now it isn't(sort of), does this make sense?!?!?

1377c - Was Leaking Down, now it isn't(sort of), does this make sense?!?!?

Joined: November 5th, 2003, 8:29 pm

March 17th, 2011, 2:24 am #1

My stock 1377c started leaking air on low pumps out the barrel with pistol cocked...so I took it apart, wiped some grime out of the valve and delrin/plastic seal. Noticed the cone shaped delrin seal was rough feeling, took some 1200 grit paper and light sanded it smooth, put it together...

Cocked gun and put a pump in, now its leaking louder and faster! Dumped the air and cocked it and started pumping again, at around #5 or #6 it stopped leaking out the barrel so I pumped it up to 10 and let it set for 10 minutes, dry fired it and it sounded louder than previous...

Cocked it and pumped it 15 times and let it set for another 10 minutes, dry fired and it was loud, now I cock it and give it 1 pump, no detectable leaking and holding that 1 pump of air for about 5 minutes but after 10minutes its leaked empty!

Any thoughts on what to do?

Regards,

Tony
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Joined: December 3rd, 2008, 11:42 pm

March 17th, 2011, 2:48 am #2

Might have to much oil in the valve shoot it a few times.
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Joined: November 5th, 2003, 8:29 pm

March 17th, 2011, 3:53 am #3

and it was dry upon reassembly but there very well could be more oil that migrated into it as the pump tube, pivots/linkage was well lubed...maybe I need to go through it once more...

Regards,

Tony
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Joined: November 28th, 2002, 6:26 pm

March 17th, 2011, 4:03 am #4

My stock 1377c started leaking air on low pumps out the barrel with pistol cocked...so I took it apart, wiped some grime out of the valve and delrin/plastic seal. Noticed the cone shaped delrin seal was rough feeling, took some 1200 grit paper and light sanded it smooth, put it together...

Cocked gun and put a pump in, now its leaking louder and faster! Dumped the air and cocked it and started pumping again, at around #5 or #6 it stopped leaking out the barrel so I pumped it up to 10 and let it set for 10 minutes, dry fired it and it sounded louder than previous...

Cocked it and pumped it 15 times and let it set for another 10 minutes, dry fired and it was loud, now I cock it and give it 1 pump, no detectable leaking and holding that 1 pump of air for about 5 minutes but after 10minutes its leaked empty!

Any thoughts on what to do?

Regards,

Tony
...from sealing at first, but subsequently got blown out.

Steve
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Joined: November 5th, 2003, 8:29 pm

March 17th, 2011, 4:10 am #5

with brake cleaner and letting it dry before reassembling the valve. The gun is designed to hold one to 2 pumps in factory form, right?

Any other suggestions, I seem to be fixated in 1377 mode right now so it's driving me nuts, lol?!?!?

Regards,

Tony
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Joined: June 5th, 2006, 12:49 am

March 17th, 2011, 5:56 am #6

My stock 1377c started leaking air on low pumps out the barrel with pistol cocked...so I took it apart, wiped some grime out of the valve and delrin/plastic seal. Noticed the cone shaped delrin seal was rough feeling, took some 1200 grit paper and light sanded it smooth, put it together...

Cocked gun and put a pump in, now its leaking louder and faster! Dumped the air and cocked it and started pumping again, at around #5 or #6 it stopped leaking out the barrel so I pumped it up to 10 and let it set for 10 minutes, dry fired it and it sounded louder than previous...

Cocked it and pumped it 15 times and let it set for another 10 minutes, dry fired and it was loud, now I cock it and give it 1 pump, no detectable leaking and holding that 1 pump of air for about 5 minutes but after 10minutes its leaked empty!

Any thoughts on what to do?

Regards,

Tony
Acetal is a hard seal material so it's not forgiving of eccentricity. Nothing's to say
that either the valve seat or seal are perfectly concentric. It's common practice to
apply some lapping paste and spin the seal on the seat (e.g. with drill).
To make your own lapping paste, scrape some of that 1200 grit off with a blade and mix
with cutting oil or other.
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Joined: September 23rd, 2002, 6:16 pm

March 17th, 2011, 12:59 pm #7

with brake cleaner and letting it dry before reassembling the valve. The gun is designed to hold one to 2 pumps in factory form, right?

Any other suggestions, I seem to be fixated in 1377 mode right now so it's driving me nuts, lol?!?!?

Regards,

Tony
most likely 5 or more pump strokes before a shot. So if it leaks down in a minute likely a non issue.

with valve in hand and a rubber tipped blowgun in hand fill the valve with air. Bubble check it in a tub of water and see where the leak is from.
I am happy with pumpers if the valve will take air and hold it from that blowgun.

What are you hoping for Tony?
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Joined: November 5th, 2008, 8:23 pm

March 17th, 2011, 2:43 pm #8

Acetal is a hard seal material so it's not forgiving of eccentricity. Nothing's to say
that either the valve seat or seal are perfectly concentric. It's common practice to
apply some lapping paste and spin the seal on the seat (e.g. with drill).
To make your own lapping paste, scrape some of that 1200 grit off with a blade and mix
with cutting oil or other.
the check-valve in upside down.
The slanted end end goes toward the intake port and the flattened end goes toward the exhaust valve and spring.
Might be worth a check.
Thanks
Ray
Last edited by ray1377 on March 17th, 2011, 2:43 pm, edited 1 time in total.
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Joined: November 5th, 2003, 8:29 pm

March 17th, 2011, 3:19 pm #9

most likely 5 or more pump strokes before a shot. So if it leaks down in a minute likely a non issue.

with valve in hand and a rubber tipped blowgun in hand fill the valve with air. Bubble check it in a tub of water and see where the leak is from.
I am happy with pumpers if the valve will take air and hold it from that blowgun.

What are you hoping for Tony?
Was hoping for use in the 1 - 5 pump range with consistent velocities. I'll have to dig up that rubber tipped attachment for my compressor...thanks.

Regards,

Tony
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Joined: November 5th, 2003, 8:29 pm

March 17th, 2011, 3:22 pm #10

Acetal is a hard seal material so it's not forgiving of eccentricity. Nothing's to say
that either the valve seat or seal are perfectly concentric. It's common practice to
apply some lapping paste and spin the seal on the seat (e.g. with drill).
To make your own lapping paste, scrape some of that 1200 grit off with a blade and mix
with cutting oil or other.
with the pin that's leaking right?

So the synthetic seal is acetal?

Could I use Flitz or JB Bore Paste to lap with?

Regards,

Tony
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