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Leaking from the nozzle during pumping

Written by Ben
Last updated on 2008-02-15


The water gun is leaking from the nozzle while pumping, but no other time. Sometimes the leaking stops as you continue to pump.


This is the most common problem in need of repair in water guns. On some older guns such as the XPs and CPS series, the problem can fix itself with a little use. Keep pumping and it might improve. If it doesn't improve, identify what sort of water gun you have and follow the guides below.

It has been reported that the stickers of some water guns report that leaking from the nozzle is completely normal. Manufacturers seem to know about this problem as well, I suppose.

Old style valve repair

If your water gun is an old XP or CPS series water gun that uses a pull valve, the problem is that the spring inside of the valve doesn't push the valve closed all the way or that the seal on the gun isn't aligned correctly or has fallen out.

If the problem improves (that is, there is less leaking) as the gun is pumped up more, the problem likely is that the valve doesn't close all of the way. Put a rubber band or two on the firing valve like in the photo below. This is called the "rubber band repair."

Adding rubber bands will close up the valve. Some people do this "repair" to their water gun regardless of whether or not it leaks from the nozzle just because it is so simple and prevents a pesky problem. If you perform the rubber band repair and it does not stop leaking from the nozzle, your problem likely is the one below.

Open up the firing valve. If you see that the rubber seal has come off, that is your problem. This problem can be fixed by first waiting for the valve's pieces to dry off, and then epoxying on the seal.

Be careful when working with firing valves. It has been reported that if you pull the pin in the firing valve back too far, the valve won't close completely any longer.

Your water gun can have a combination of both problems. If you perform the second repair and it still leaks, try the second repair in addition to the first one.

Another very rare possibility is that the plastic piece that holds the seal could have a crack in it. That can make one side of the seal not seal. Check the seal assembly for this problem, and if you notice it, epoxy the crack so that the assembly is as it should be.

Water Warriors/Max-D valves

Newer water guns use a ball valve trigger which removes the problem of the seal falling off because there is no seal. The problem is similar to the first one mentioned about. The valve isn't closing completely. There's a pretty good guide on m15399's website about repairing these types of water guns. Here's another great website about repairing a Super Soaker water gun's valve.

Misalignment problem

The problem could also be that the trigger and firing pins are out of alignment, making it so that the valve can't close completely because the firing pin or trigger can't move forward completely. Open up the gun and realign them parts if you suspect this is the problem.

As always, if you have any other questions or problems, feel free to post at our repairs forum.

Links to other guides

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