1978 1377 advice please

[edwardsa]

Dear members

I've recently bought this pump up pistol and a friend fitted a new seal set. It worked fine for 10 shots (3.5 ft lbs 7 pumps), then started blowing air out again. Took it to Blackpool today and Lloyd said he thinks the valve is sticking open but he hasn't got a gun
smith currently. Any advice would be much appreciated as I'm not too technically minded.

Thanks
Andy

[T 20]

It could just be the smallest amount of dirt under the exhaust valve holding it open --- I've never had a valve stem stop the valve moving.

I have put oil in the pump before now in an attempt to flush the valve through, but I normally end up stripping the valve.




All the best Mick

[--ped--]

if the air is coming down the barrel the stem will most likely have gone and the original design type is obsolete -they can be resealed but costs more to do than fitting the new type overmoulded stem
and i often swap the old valve for a comlpete new one on rebuilds as by the time you have replaced the seals and spent the time cleaning them up it makes sense time wise and i do a part ex for the old valve and then when i have a few spend the time cleaning them up and resealing
they're not hard to do and the hardest job is getting the circlip off the solid pivot pin or knocking the roll pin out if it has the later one fitted
when you strip it take care when removing the trigger so as not to loose the safety ball and spring