Servicing an HW75

[Adam77K]

Hi folks.

Does anybody have a list of the o-ring sizes and specs required to fully service an HW75? I don't want to pay through the nose at Chambers or somewhere when I would have thought some ordinary nitrile o-rings should do the job.

Any links to strip down guides, google's drawn a blank?

[mickson]

Diffacult one, have U tried e mailing the main importers for info..mike..

[BigDuncs]

I got my HW75 serviced a few months ago at Hull and it was around £45 IIRC.

Too good a pistol for myself to play with even though I bought the o rings etc

[Adam77K]

BigDuncs, where did you get the o-rings and do you remember the sizes?

[BigDuncs]

Adam
Prob Chambers but can check tonight. I would suggest its best to use the correct ones as I have had the experience of a real runaround with the wrong spec rings in my Gamekeeper. A few pops and poops in the wrong places and at the wrong times!!!

[BigEars]

I got my HW75 serviced a few months ago at Hull and it was around £45 IIRC.

Too good a pistol for myself to play with even though I bought the o rings etc

How long did they take to do it? I'm far too violent and clumsy to attempt fixing my own one so £45 would be money well spent AFAIC.

[royalscotsgrays]

i got a box of o-rings from my local market it was a box of 100 or 200 and i found a lot of them fit air guns like meteor piston seals and so on and for £4 a box you can't go wrong kind regards mark

[Adam77K]

Thanks Mark, I have a box of assorted o-rings £2 odd from Maplins. I'd like to know what sizes I need before stripping the gun though.

[BigDuncs]

Found the receipt and rings.

I bought them from Chambers 2 x OR113 rings for £3 each + 2.56 P&P in Feb 08. The ring is 22mm in diameter - outer edge to outer edge and the material is about 3mm in diameter so the inner diameter is 16mm. Hope this makes sense - if not, let me know!

Should say - that I bought them but didn't use them so no guarantee that they are right. Think they came from the exploded diagram and are described as "piston O ring"

[Adam77K]

Thanks

I'm going to have a go stripping the pistol down this weekend, after reading Alan's post on the other thread, and clean and re-lube and then I'll see what's what with the o-rings.

My 75 works fine but as you compress the air there's a spot toward the end where a tiny bit of air leaks past the cylinder seal. As you push the lever down you can hear a quiet pffft sound, but luckily when fully cocked it seals 100%.

Also occasionally on firing the valve sticks a bit so it doesn't release all the air. It still fires fine but there's a little pop when you open the action again. It's never been serviced since 1993 so it's probably gummed up a bit. So it most likely just needs cleaning out and relubing and a couple of new o-rings wouldn't hurt.