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Thread: Leaking THEOBEN Rapid 7

  1. #1
    Join Date
    Oct 2021
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    Leaking THEOBEN Rapid 7

    Are there any Rapid 7 enthusiasts out there who could give me some answers to the following queries. I have a Rapid 7, 22, well it is now !,(serial number 008838) the previous owner having converted it from a 20 calibre, which has never bothered me, and for 10 years gave me good unbroken service, then just before Covid hit, the rifle seemed to start losing air, no trouble I thought just strip it down and replace all seals. This I did , also I replaced the Metal valve with a Acetal valve and matching new exhaust valve of T.R Robb, doing away with fitting the white nylon seal, which goes with servicing the Metal valve. The result of all this ?, still it lost air, and in disgust I have put it away ever since, until now , there is no point having something that does not work !, so I will try again, but a few questions !. 1, Is it possible to narrow down , where the leak is ?, It,s not the bottle as this holds air without any problems when not screwed onto the rifle, also I have read that if you cycle the pellet probe forward with the bottle screwed on, fitting a tight fitting bag over the muzzle will show if air is leaking that way, this also draws a blank. 2, I have many seals I purchased with the rifle, are these still valid to use ?, or would it be better to use new ones and if so, of whom do you recommend ?,as we know Theoben Ltd is not sadly a option ! 3 , Although the Acetal valve and exhaust valve have done no work, should I use new ones again as the rifle is stripped down ?, and again who would you recommend ?. 4 ,Now you can get quick fill adapters that make unscrewing the bottle to fill with air a thing of the past, this quite appeals to me as getting contamination is always a risk when unscrewing the bottle, plus it does not need you to dry fire the rifle to lesson the air pressure when unscrewing, If anyone has had this modification your opinion ?, did you have any problems if it,s on a older bottle ?, mines stamped 1987 !. Any help would be appreciated, All the best !, Elwyn

  2. #2
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    Hi send a pm to KevG on here, he's a top man. Atb Mick.

  3. #3
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    good advice above.

    In terms of the leak... with the bolt closed, does it leak out of the muzzle ? A balloon on the muzzle will tell you if it's too slow for it to be obvious just using a wet finger. If so it'll be leaking through the valve. If not, it'll be someplace else ! There's not many seals on a Mk1.

    Quickfill adapters are a great idea, and save a lot of hassle. Dr Bob's would be my choice, but unscrewing the valve from the bottle can be a PITA. Other variants use the existing valve, but push the bottle further forwards, compromising balance. Maybe OK with a 280cc, but not ideal with a 400cc.
    Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.

  4. #4
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    Oct 2011
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    I'd suspect the T. R. Robb valve. When you replaced it did you back off the little locating grub screw by half a turn? It's only there to stop the valve rotating, too tight and it buckles the O rings.
    The Early Bird May Get The Worm, But It's The Second Mouse That Gets The Cheese !!

  5. #5
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    I've a Dr Bob's q/fill on my mk2, great bit of kit. If you do get one just make sure you get the one for the bottle, as 280cc and 400cc are different. Atb Mick.

  6. #6
    Join Date
    Jan 2013
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    2,380
    There's only a couple places a rapid will leak. Firstly bottle oring weeping from being screwed on and off, especially if it's not lightly lubed with silicone grease (very lightly - you don't want silicon grease getting into metal to metal contact points.)
    Secondly reg oring failing, if its regged.
    Finally the valve or valve stem seat into valve body.

    If its been messed with to change calibre, it won't hurt to send it to kev G to be properly serviced and set up. He knows them inside out and is very very reasonable with what he charges when you weigh up parts and time he puts in.

    They're easy to work on but this often means any monkey with tools won't mind having a go and getting it wrong.
    Hope this helps,

    Dan

  7. #7
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    Sep 2010
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    Exeter
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    35,880
    Quote Originally Posted by elwyn View Post
    Are there any Rapid 7 enthusiasts out there who could give me some answers to the following queries.

    I have a Rapid 7, 22, well it is now !,(serial number 008838) the previous owner having converted it from a 20 calibre, which has never bothered me, and for 10 years gave me good unbroken service, then just before Covid hit, the rifle seemed to start losing air, no trouble I thought just strip it down and replace all seals. This I did , also I replaced the Metal valve with a Acetal valve and matching new exhaust valve of T.R Robb, doing away with fitting the white nylon seal, which goes with servicing the Metal valve. The result of all this ?, still it lost air, and in disgust I have put it away ever since, until now , there is no point having something that does not work !, so I will try again, but a few questions !.

    1, Is it possible to narrow down , where the leak is ?, It,s not the bottle as this holds air without any problems when not screwed onto the rifle, also I have read that if you cycle the pellet probe forward with the bottle screwed on, fitting a tight fitting bag over the muzzle will show if air is leaking that way, this also draws a blank.

    2, I have many seals I purchased with the rifle, are these still valid to use ?, or would it be better to use new ones and if so, of whom do you recommend ?,as we know Theoben Ltd is not sadly a option !

    3 , Although the Acetal valve and exhaust valve have done no work, should I use new ones again as the rifle is stripped down ?, and again who would you recommend ?.

    4 ,Now you can get quick fill adapters that make unscrewing the bottle to fill with air a thing of the past, this quite appeals to me as getting contamination is always a risk when unscrewing the bottle, plus it does not need you to dry fire the rifle to lesson the air pressure when unscrewing, If anyone has had this modification your opinion ?, did you have any problems if it,s on a older bottle ?, mines stamped 1987 !. Any help would be appreciated,
    All the best !, Elwyn
    Easiest way to find a leak is put it in a bath of water & look for the bubbles, obviously remove the scope & stock first & completely dry it after.
    If it's 10 years since a service every seal is probably shot.

    You need to fit the black valve & valve stem as a matched pair from the same maker Dr Bob is quality supplier, he also makes Quick Fill's but some stock cutting may be required,
    Best fittings also do a QF but theirs has the option of an extension that pushes the bottle fwd so the stock doesn't need work.

    Any seals more than a few years old are probably toast, there are loads of seal kits on the bay, try A1 Tackle (Bagnall & Kirkwood) theirs are good.

    There are also two dedicated Rapid forums both with real Rapid experts on them.

  8. #8
    Join Date
    Jun 2012
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    North Wales
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    3,179
    The bottle connector to main block seal can be erratic. Think Big Al uses a different seal to original spec.

  9. #9
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    Oct 2021
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    Old Radnor, Presteigne
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    Thank you to all those that replied.

  10. #10
    Join Date
    Feb 2012
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    gateshead
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    hope you get it sorted bud

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