Tuning Benjamin Marauder .25 Repair (Fill Assembly)

Hello all! I'm new here but have been shooting airguns for some time. Hope to figure this issue out so I can get back to it!

I didn't have access to one of my guns for a while because of a move, and my Marauder unfortunately no longer holds air. There is noticeable barrel rust, but it seems to be cosmetic and I think I've traced the leak to the fill assembly as I can hear air coming out of it. How safe would it be for me to repair the gun myself by installing a new fill assembly? I'm having trouble finding solid information on this issue and would appreciate advice from people more experienced with airgun repair than I. 
 
Ryan,

It is absolutely safe for you to repair your rifle.

The one safety issue is to be absolutely sure there is no air in the rifle when dealing with the fill port or gauge.

There is an o-ring (118 ) that could be leaking.

Too, the foster fitting probably has some black stuff on it.

Remove the fitting and replace with a few wraps of plumber’s tape.

You may want to remove the gauge and do the same…

That should take care of any leaks.

If there is air coming from the barrel after these repairs then it is coming from the valve.

O-ring there and the valve poppet.

These too are easily repaired…

Remember to coat the o-ring on your rifle with silicone grease..
 
Ryan, As PeeWee says, de-gas your gun and unscrew just the foster fitting if you want and replace the small O-ring. As you can see by my photo the flathead screw has no threads, just help to extract the piston with O-ring. I have a pack of these and can send you a couple if you DM me your address. I would use a few wraps of the yellow high pressure plumbers tape to finish the job.

Patrick

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