GTA

All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: larspawn on April 10, 2019, 04:22:01 PM

Title: Disco valve stem vs Marauder?
Post by: larspawn on April 10, 2019, 04:22:01 PM
As luck would have it...

I just placed order the other day for a new valve stem for the PROD which started leaking.  I had replaced all the o-rings but still slow leak out barrel so I'm suspecting valve stem?  Anyway, I noticed that it is the same as for the Marauder so I bought 3 they were so cheap. 

Ok so I go down and pull out my old Disco.  Guess what?  It's leaking out the barrel.  argh.  We'll hoping its just o-rings but on the off chance it is also the valve stem:

my question is...are the valve stems on Discos the same as the valve stem on the PROD and MROD?

This is the result of being out of the game for several years and not exercising the equipment.  I kind of feel like every gun I pick up now is going to have some problem.  Argh!!!!

Title: Re: Disco valve stem vs Marauder?
Post by: dmeguy on April 10, 2019, 04:53:40 PM
You can use a Marauder valve stem but it is smaller diameter, so you'll need to sleeve the back half of the valve. A brass hobby tube cut to length and glued in place works perfect. I don't remember the size.
Title: Re: Disco valve stem vs Marauder?
Post by: rsterne on April 10, 2019, 05:00:21 PM
The tube you need is 5/32" OD x 0.014" wall, made by K&S Hobby Tubing.... This reduces the hole in the valve to a 1/8" ID to fit the MRod valve stem.... You should check the length of the stem (the distance it protrudes behind the valve)…. I'm pretty sure the MRod stem is longer, which will reduce the hammer travel and you may lose a bit of velocity, or have to readjust the hammer spring preload.... I grind the end of the MRod stem so that it is the same length as the Disco stem.... You can go about 1/16" shorter and gain hammer stroke, but you have to be careful that the cocking pin doesn't hit the front end of the slots, or the back of the bolt, on firing.... Not only is that hard on the pin, but is the chief cause of the bolt handle flipping up in a Disco when the gun is fired....

Bob
Title: Re: Disco valve stem vs Marauder?
Post by: larspawn on April 10, 2019, 08:38:58 PM
Hmm, might just be easier to order new Disco valve stem for the $1.80 and $4 shipping.

Thanks for the info. Impressed with the knowledge here!