Benjamin Marauder leaking air from front fill valve

[soarwitheagles]

Hi everyone!

Haven't been here in a long, long time!

Nice to be back.

My trusty Benjamin Marauder began to leak air out of the front of the fill valve and the front of the gun [the place where I attach the hose from the SCUBA tank].

Can anyone give me some tips/hints on how to fix this?

Thank you,

Soar

[Doug Wall]

They're pretty simple. Take it out, take it apart, inspect for dirt, corrosion, or bad seal, clean, replace seal if necessary, reassemble, put back in gun. If there's significant corrosion, just replace the whole thing. I don't recall if if you need thread sealant(tape), or if it is a straight thread with a seal at the bottom.

[mtsheron70]

They're pretty simple. Take it out, take it apart, inspect for dirt, corrosion, or bad seal, clean, replace seal if necessary, reassemble, put back in gun. If there's significant corrosion, just replace the whole thing. I don't recall if if you need thread sealant(tape), or if it is a straight thread with a seal at the bottom.

Doug beat me to the punch.  I would have suggested exact same thing and I too wonder on the thread tape aspect.

[ezman604]

Of course make SURE to degas before starting this procedure!!!

[AlanMcD]

Of course make SURE to degas before starting this procedure!!!

Agree - don't trust the leak to do it for you.  Sometimes they still hold some level of pressure, and if it were to be a few hundred psi the gauge could make it look empty.  At a minimum, that pressure would probably mess up the threads as the cap popped out.

I always like to take the gauge out before the end cap, as worst case it leaks when backed out (in truth, that is often how I degas - I just loosen the gauge and leave it for a while).

[Ribbonstone]

Welcome back.

Not a M-Rod...but same system....same 3 possible leaking points. 




1.The nipple itself can leak if the little check o-ring is fouled or worn out.
2. Nipple thread seal.
3. Internal o-rings that seal the end cap to the air tube.


Probably best to just remove the end cap,and the fill nipplefrom the end cap,and deal with all 3 at the same time.

If you are 100% sure ithe leak is from #1 or #2, could just remove/clean the fill nipple. Might be able to unscrew just the nnipple,but usally the endcap wants to turn out with it.

DO NOT BELIEVE THE GAUGE....as they mentioned, they not so good at reading "zero"and even 50 PSI left over  is enough to get you into trouble.

HAve one that was stuck at 2200PSI....really had to handle that rifle like a  bomb even though all the other tests showed it was empty.....so I don't trust the ones that read zero,as they could be just as broken.

[soarwitheagles]

Wow, thank you for being so incredibly kind and helpful!

I was just thinking, 50 years ago I would probably need to visit 2-3 libraries or write a letter to Crossman!

I am in desperate need of fixing this leak.  We are having a massive skunk invasion and they keep eating our honeybees on a nightly basis.  I have never seen so many skunks ever before...so not sure why this is occurring.  I have lost track of how many skunks I have shot in the last two weeks!  I have been using the .25 Marauder for the back bee yard, and the Hatsan FlashPup QE .25 for the front yard, often shooting 1-2 skunks per night.  They scratch on front of the honeybee colony and then eat the bees like a darn vaccum cleaner as the bees come out of the entrances.  Nearly every time it is one shot, one kill.  I think they are much smaller than they appear and that most of the "body bulk" is actually hair!  Very different than taking possums that require anywhere from 5-10 shots.  Turkeys are also one shot, one kill.

I should have described the leak in better detail:

The air is leaking from the front of the nozzle.  I could feel the air coming out in a steady, but low pressure and when I place my finger over the hole in the filler valve, it temporarily stops the leak!

I purchased the degasser tool 4 years ago.  I will have to look for it.  Is there anyway to degas the Marauder without the tool?

Thanks!

[Doug Wall]

You can just shoot it down to no pressure. Just dry fire so you don't get pellets stuck in the bore.

[Rob M]

shoot it down to zero.. or , back off the gauge a few turns while not facing your the gauge torward your body.. once you hear the hiss stop turning.. this could also be done at the foster.. but , shooting till empty wont take long and far safer

[bnowlin]

With all the mods now days you just about have to loosen the air gauge slightly and only remove the fitting to clean out or replace.  If you  have a modded or balanced valve don't dry fire.
Bob

[KevinJBrown]

Not sure this helps or where it might be leaking, but if it is leaking out of the fitting after pressurizing and then disconnection (out of the rifle). Then the problem is probably the same as what I had and seemed most likely to be the check valve. If it is a problem with sealing when you are trying to pressurize the gun with the tank/pump connected, the previous comments seem more appropriate.

[Ribbonstone]

Yeah...with care,well away from anyone else,will often shoot it down to "nothing" and then slowly lkoosen one fitting or the other (fill nipple/end cap/gauge) listening for a leak....if I hear one,will just let it sit until it doesn't hiss any more.

Rven when I  don't hear one, sill loosen 1/4 turn at a time,keeping my body and anything important out of the line of flight.

If I screw up,  will have a new hole in the shop wall...but not in me.

[AlanMcD]

Bleed it down out the pressure gauge - the gauge seals with an o-ring at the bottom of of the fitting, and it takes a good 5+ thread turns to get it there.  Back it out a half or 3/4 turn or so and you will start to hear the hiss - the gauge can't blow out if you only loosen it a turn or so.

Daystates don't have degassing tools - they degas with the gauge the same way.  I figure if it is good enough for Daystate . . . .

[jeffsenpai]

I had the same problem as you recently. I just replaced the male quick connect adapter with the one here

I ordered an extra for backup, and what do you know, my Benjamin Maximus just TODAY came up with the same problem! What luck I have. Luckily it isn't too hard to switch out.