When I resealed my 1rst variant 760, someone suggest an O-ring, to replace the quad seal. I donít know if they would be the same size as for a 140/1400. Maybe some else can confirm.
Baker airguns and Mac1 will sell you multiples of the quad ring. Just ask them for some.I suggest some moly paste on the trigger and sear components. The smooth function of the sear and the trigger is important for proper sealing of the valve cap. Iíd check the nipple on the valve for nicks or dings but thatís unlikely.Can you hear or feel the valve cap physically setback and seat against the sear on the first or second pump? Some guns make an audible click.It sounds like you might be pumping too fast?Because of the pump design 1400ís make the most power when pumped slowly. When you extend the pump arm you should hear a momentary hiss as the somewhat restricted intake port admits air past the piston. I always pause and count ď1 MississippiĒ at the top of every stroke to make sure the pump chamber completely fills. You should hear/feel the valve cap setback at the end of the pump stroke. Resistance should start building after the third pump and the last two should be pretty hard to stuff in there.If you donít hear that hiss when you open the pump itís time for some oil.Hope some of this helps.Oh yeah. The blowing the bolt open thing is a problem. A new Oíring helps but best to get in the habit of making sure the bolt is flipped all the way down before shooting. I prefer the 140 style breech cover on my first model. Itís much more secure.