crosman 140

[martin bingham]

i have picked up a fairly straight 60's 140,when pumped it just goes "phut" from the barrel on the end of every 'stroke', anyboy know the most likely cause and fix?,
thanks

[45flint]

i have picked up a fairly straight 60's 140,when pumped it just goes "phut" from the barrel on the end of every 'stroke', anyboy know the most likely cause and fix?,
thanks

That’s the sound of a leaky seal. Have you tried some oil in the pump to see if that will seal it? If not a seal kit is in order. I’ve only sealed a 101, but I think a 140 is not bad do work on.

[smallholder1]

I bough one and did the same ordered seal kit from USA but put some pellgun oil in pump and it cured it.....holds air for ever now .......i leave with one pump in it

[--ped--]

its the quad seal that needs replacing but older models can suffer wear on the valve body and one I have(4th variant) had a worn trigger that allowed the release block to sit further back letting the quad seal leak
afaik leaving the 140/1400 130/1300 and self cocking 760 with air in for prolonged periods is bad for the quad seal
the quad seal is a bs008 xring and can be fiddly to replace the 140 will potentialy go over 12 very easily so I made blow off pistons like the UIK sharps and later c9a series bluestreaks

[martin bingham]

thanks for the info,i put a drip of oil on it last week,before that there was no resistance at all,now it builds pressure only to let it go right at the end of the pump stroke,i will buy some seals after christmas and have a go at a full service,
atb

[Mark D]

thanks for the info,i put a drip of oil on it last week,before that there was no resistance at all,now it builds pressure only to let it go right at the end of the pump stroke,i will buy some seals after christmas and have a go at a full service,
atb

Or you could pm Lawrie Amatruda and see if he will do a complete reseal for you, he is only in Banstead. He has done many a pumper in his time

[Hsing-ee]

Or you could pm Lawrie Amatruda and see if he will do a complete reseal for you, he is only in Banstead. He has done many a pumper in his time

He is an excellent engineer, and why not treat the old rifle to some new guts? It will make sure it is working at its best, which I believe is really quite good with these older Crosmans. Yea, 'tis a rifle that old greybeards would slay the galvanised iron dustbin at a single shot....

[DT Fletcher]

thanks for the info,i put a drip of oil on it last week,before that there was no resistance at all,now it builds pressure only to let it go right at the end of the pump stroke,i will buy some seals after christmas and have a go at a full service,
atb

Pneumatics can be damaged by regular oil. Only silicone oil, as used for hydraulic systems, can be safely used. Crosman oil is the best known but there are a few others. MAC-1 in the US, sells a special oil (secret sauce) that is the oil for motorcycle front forks.

[--ped--]

thanks for the info,i put a drip of oil on it last week,before that there was no resistance at all,now it builds pressure only to let it go right at the end of the pump stroke,i will buy some seals after christmas and have a go at a full service,
atb

they're not hard to do but watch out for the nylon bushing under the rear breech screw and you have to drift the rear threaded insert out
if your piston washer is worn fit an o'ring piston head but would really recommend leaving a bit of head space to limit power output/pump stroke
with the blow off pistons in mine power is limited to around 7-8fpe

[martin bingham]

i had never heard of a 'quad' seal,a quick google led me to 'anotherairgunblog',full of pics inc a stripdown of the same later alloy trigger block 140 model as mine,maybe letting a crosman guru do the work is the way to go.
i have also found on 'tbay this kit, 371232840249,it says it includes the quad seal.if ok? it will be ordered asap,i presume that this is all that is needed,this will be on the backburner til spring.
thanks

[DT Fletcher]

Everything you ever wanted to know and more.

https://www.amazon.co.uk/Crosman-Com.../dp/1499555008

[johnbaz]

I have a copy of Dena's book, A smashing resource for thw 14** series


John

[--ped--]

i can do you a seal set minus the piston head and inlet (I am looking at replicating the early oring type in various length's to adjust valve volume) for £2.50 plus a quid postage
seals are
inner exhaust cap quad seal
outer exhaust cap o ring
inner valve case seal
outer valve seal in either 70 or 90
probe seal
I can also supply an o ring piston head in delrin

[martin bingham]

i can do you a seal set minus the piston head and inlet (I am looking at replicating the early oring type in various length's to adjust valve volume) for £2.50 plus a quid postage
seals are
inner exhaust cap quad seal
outer exhaust cap o ring
inner valve case seal
outer valve seal in either 70 or 90
probe seal
I can also supply an o ring piston head in delrin

nice one,i will pm you later,i want to wait a bit til the post etc is back to normal.