Author Topic: Poor Marauder leaking from the fill nipple. (Read 3469 times))

jeffsenpai · « **on:** June 07, 2020, 10:14:29 PM »

Have not shot in a while, today I grab the Marauder off the rack and its at 0 psi. Sad.

So I grab the hand pump and get to work. Once the rifle is full, I degass the pump and notice air is hissing right out the tip of the fill adapter! I can hear and feel air coming out

I tried to tap on it gently, refill with the pump and release the pressure quickly, hoping the force would make the valve work to hold air.

Sadly, it just sits here now, slowly hissing away the hard work that went into pumping.

If I take off the fill nipple fitting, what am I looking for? Should I just replace the whole part?

ShakySarge · « **Reply #1 on:** June 07, 2020, 10:16:49 PM »

Take just the nipple off and check the seal on the check valve for dirt or debris. use just a tad of pure silicone oil or pure silicone grease on the oring and it should resolve the issue. It should look similar to this.

jeffsenpai · « **Reply #2 on:** June 07, 2020, 11:02:39 PM »

Mine looks a little different than yours. The O-ring looks a bit worn, is that a possible cause for a leak there?

ShakySarge · « **Reply #3 on:** June 07, 2020, 11:29:02 PM »

It may be worn or degraded. They look different but are the same general design. The one I showed was from a fill port on an old paintball tank so I wouldn't have to take one off of my guns. Try some silicone oil or silicone grease on the o-ring and it may rejuvenate it. If not, just replace the oring. any hardware store should have what you need, just take the old one in with you.

Rob M · « **Reply #4 on:** June 08, 2020, 12:15:23 AM »

just solve it permanently and get one of these, theyre self contained, sprung, and extremely reliable

jeffsenpai · « **Reply #5 on:** June 08, 2020, 12:46:21 AM »

Quote from: Rob M on June 08, 2020, 12:15:23 AM

just solve it permanently and get one of these, theyre self contained, sprung, and extremely reliable

Looks good, I will try that out. Thanks.

Greasing the O-ring and reassembly didn't help. The air leaks out slower, but I can still feel it bleeding out the tip. Gonna buy some spare o-rings too.

Chris USA · « **Reply #6 on:** June 08, 2020, 06:48:13 AM »

The one on my Maximus started leaking. I took it apart and cleaned and re lubed it. Mine looks like the second picture. It did it again later, so I pulled it again and did some lapping compound in a drill and replaced the o-ring and it is fine again. I did order a new one from Crosman and now have it ready to go in case it happens again. Never had an issue with the Gen. 2 M-rod,... so far. Several thousand shots on the M-rod.

csitas · « **Reply #7 on:** June 08, 2020, 10:40:46 AM »

This just proves all things have a life span. No matter how small. pays to keep track of your equipment.

nervoustrigger · « **Reply #8 on:** June 08, 2020, 12:32:59 PM »

The check valve of most Foster fittings will use a -006 size O-ring. Super easy to fix...the bigger concern for me is developing a leak at the threads from removing and reinstalling the fitting. I do my best to remove all the old PTFE tape and apply fresh and that almost always works on the first try.

If you can put your hands on a 90 durometer O-ring, that would be best. A hard compound better resists both abrasion and extrusion failure which are the two primary issues with a check valve. A 70 durometer should work fine though, it just may not last as long. For the O-ring material, plain old Buna-N works great and so does polyurethane.

Rob M · « **Reply #9 on:** June 08, 2020, 12:55:13 PM »

Quote from: nervoustrigger on June 08, 2020, 12:32:59 PM

The check valve of most Foster fittings will use a -006 size O-ring. Super easy to fix...the bigger concern for me is developing a leak at the threads from removing and reinstalling the fitting. I do my best to remove all the old PTFE tape and apply fresh and that almost always works on the first try.

If you can put your hands on a 90 durometer O-ring, that would be best. A hard compound better resists both abrasion and extrusion failure which are the two primary issues with a check valve. A 70 durometer should work fine though, it just may not last as long. For the O-ring material, plain old Buna-N works great and so does polyurethane.

also a very good point..

kbstingwing · « **Reply #10 on:** June 08, 2020, 05:41:47 PM »

Ah, Jeffsenpai-san, silicone oiling every 5-10 fills with about 5 drops of silicone oil will help keep the o-ring in good condition and slow charging air will keep it from over heating and damaging the o-ring,
I put silicone oil in the charging whip and let it flow with the air into the gun, very easy to do.

Kevin-san

Habanero69er · « **Reply #11 on:** June 08, 2020, 05:51:43 PM »

I had the same issue with my Rainstorm-I the other day. The rifle didn't loose air, but after shooting a couple magazines, I refilled & when I degassed the fill line, all the air came out. Removed the nipple, took out the check valve only to see some debris & a nick in the o-ring. Replaced the o-ring, applied some silicone oil, re-wrapped the nipple threads with three wraps of Teflon tape.
Refilled with air & it started leaking out the muzzle. I then cocked the side lever, leak stopped & it filled. All's well now.

jeffsenpai · « **Reply #12 on:** June 11, 2020, 07:00:47 PM »

Just to update. I ordered the replacement adapter Rob M recommended. installed it, and forgot to put PTFE tape on threads. So after filling it to 3000 PSI it slowly leaked out. Doh. That is OK though, as I forgot to add silicone grease on the small o-ring anyways.

So I reinstalled it with PTFE tape on the threads, silicone grease on the small o-ring, and it has held at 3000 PSI for two nights now.

Thanks all for the advice. Still have spare o-rings, and a spare fill adapter on the way anyways, in case I have need in the future.

Rob M · « **Reply #13 on:** June 11, 2020, 07:07:04 PM »

good to hear !

ShakySarge · « **Reply #14 on:** June 11, 2020, 08:17:50 PM »

Glad you got it fioxed up.

KevinJBrown · « **Reply #15 on:** June 11, 2020, 08:44:19 PM »

Glad to hear you got your Marauder up and holding pressure. My replacement is supposed to be shipping any day now.

Since it had the same symptoms I'm assuming the same problem.

Question on the silicone oil being recommended. Will any kind work as long as it's 100% pure silicone oil? There is a considerable difference in price in what is sold in .25 oz tubes for air gun lube and what is sold as acrylic pouring lubricant (i.e.) or other lubricants.

I want to have some on order to start using when my marauder arrives so I'd like to know what to order.

Habanero69er · « **Reply #16 on:** June 11, 2020, 08:52:59 PM »

Kevin, silicone oil doesn't have to be high viscosity. Chamber oil works fine.

https://www.pyramydair.com/product/crosman-silicone-chamber-oil?a=311

KevinJBrown · « **Reply #17 on:** June 11, 2020, 10:16:55 PM »

I was wondering about something like this which is many times less expensive.

Any reason why this wouldn't work?

mobilehomer · « **Reply #18 on:** June 11, 2020, 10:21:11 PM »

RC car shock oil. Similar to this. It comes from 5 to 200 weight or more.

nervoustrigger · « **Reply #19 on:** June 11, 2020, 10:37:48 PM »

Glad you got it fixed. That's some pretty sweet turnaround time too. You opened the thread on Sunday, ordered the part and received it and had it fixed by Tuesday evening, and have two nights behind you to know it's holding. You're ready for the weekend now!

x2 on the RC shock oil recommend by Ken. Same stuff I use. Anything from 30W on up will be fine for this application. Since you have a hand pump, I suggest getting the 30W because it's a good weight for lubing the moving O-rings in it as well.

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Poor Marauder leaking from the fill nipple.

Author Topic: Poor Marauder leaking from the fill nipple. (Read 3469 times))