S410 still leaking

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Hairybiker59
Posts: 137
Joined: Fri May 29, 2015 11:42 pm

S410 still leaking

Tue Apr 25, 2017 10:24 am

I stripped and replaced all 0-rings on my s410 because it had a slow leak.i replaced the o ring on the pressure gauge for a dowty seal tightened it up and filled rifle.all was well until the next day I noticed it had lost air,I put a balloon over the pressure gauge and it inflated it.it the problem the dowty seal and should I replace it with a o-ring?

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ronnie12342003
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Joined: Mon Feb 06, 2017 10:01 pm

Re: S410 still leaking

Tue Apr 25, 2017 10:41 am

or the pressure gauge is nacked

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TenMetrePeter
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Location: Luton Beds UK

Re: S410 still leaking

Tue Apr 25, 2017 12:01 pm

Dowty seals are designed for flat faces without a groove. The dogleg will have a groove for an o-ring to expand into but the dowty lip may actually drop in and not be compressed. I would go back to the correct size o-ring
Luton, Bedfordshire
S400 MPR Precision 10m.
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Hairybiker59
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Joined: Fri May 29, 2015 11:42 pm

Re: S410 still leaking

Tue Apr 25, 2017 12:13 pm

TenMetrePeter wrote:Dowty seals are designed for flat faces without a groove. The dogleg will have a groove for an o-ring to expand into but the dowty lip may actually drop in and not be compressed. I would go back to the correct size o-ring

I believe that the dowty seal was at some point used on the s*series but not sure if it was the older or newer models

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Brooksy
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Re: S410 still leaking

Tue Apr 25, 2017 12:45 pm

If it was designed for an O ring, fit an O ring. Apply a tiny coating of O ring grease first, this helps it to seat correctly.
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TenMetrePeter
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Re: S410 still leaking

Tue Apr 25, 2017 1:02 pm

Also depends on where the balloon was fitted. If only on the gauge body then it may well be the gauge bourdon tube knacked as already suggested by ronnie
Last edited by TenMetrePeter on Tue Apr 25, 2017 2:04 pm, edited 1 time in total.
Luton, Bedfordshire
S400 MPR Precision 10m.
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TenMetrePeter
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Re: S410 still leaking

Tue Apr 25, 2017 1:22 pm

Screen Shot 2017-04-25 at 14.18.20.jpg
Screen Shot 2017-04-25 at 14.18.20.jpg (20.17 KiB) Viewed 830 times


If the dogleg looks like this with a groove milled into the face where the gauge threads then it deffo needs an O ring.
If it is completely flat with just the thread then a Dowty washer is indicated.
Luton, Bedfordshire
S400 MPR Precision 10m.
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Hairybiker59
Posts: 137
Joined: Fri May 29, 2015 11:42 pm

Re: S410 still leaking

Wed Apr 26, 2017 9:58 am

Removed the dowty washer and replaced with an o-ring,filled to 100 bar and left it overnight and all is good.happy days

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