rapid mk1 leaky block

[deano]

hello chaps,
got the above problem and after a little advice,
the rifle in question belongs to a guy at the club, originally his fathers who is no longer with us so as you can imagine it has some sentimental feelings attached.
now it was completely in bits upon receiving it, many parts missing and the valve bent in 2 directions and the valve block grub screw missing and a screw from a plug in there attempting to hold the valve housing in place. valve housing gouged to buggery, and the retaining grub screw hole mangled.
i have tidied everything up and replaced valve and housing and grub screw but it is still leaking from the grub screw hole once bottle is fitted, have stripped it down again and found scoring marks on the outer valve housing, obviously there is some internal burrs that i have not been able to get to which i think are causing this and in doing so creating the leak through the grub screw retaining port, hope this makes sense.
thanks in advance.

[angrybear]

For air to leak from the grubscrew means it's leaking past the valve body.
Not sure what you're calling the "outer valve housing" ? if you mean the black valve body, replace it,
which should have been done anyway if the shaft was damaged/bent.
If you mean the block machining is damaged, it might be scrap, unless it can be honed/reamed & have a custom oversize valve made.

Photo's of damage are needed, burrs can be found with a cotton bud, they snag the cotton wool.

[deano]

yes sorry meant valve body, new one fitted as well as valve stem, no difference, stll leaking through the valve body grub screw. removed valve body and there is evidence of scratch/scrape marks leading me to believe damage to the block internally. will get some pics sorted once i get 5 mins

[Ca_Varminter]

Is it just Leaking, or is it leaking when you fire it??
Are you using a Acetal Valve-body?

If it leaking just as you instal the bottle..That means the air is bypassing the Large O-ring..
If the chamber is scored, it ight be correct by a Little polishing...or might need machining!!

Good Luck,
Stuart

[angrybear]

yes sorry meant valve body, new one fitted as well as valve stem, no difference, stll leaking through the valve body grub screw. removed valve body and there is evidence of scratch/scrape marks leading me to believe damage to the block internally. will get some pics sorted once i get 5 mins

If the grub screw hole was mangled that might be burred on the inside machining, which scores the valve body.
The scrape marks will at least show where to look, assuming you pushed it straight in & pulled it straight out,
did you buy the new valve assy from a known quality seller ?