Crossover - Leak from trigger pin

[lhamilton1807]

One of the younger guys in my pball group has a crossover (thx Jimmydee for the hookup for his gear!) but it’s developed a leak from the trigger area. We’ve traced it down to the trigger pin area.

When it’s aired up, it leaks from the pin. The leak stops when he pulls the trigger, but the marker doesn’t cycle.

We replaced the seals on the transfer tube by removing it, cleaning, and adding new seals and lube so I don’t think it’s that because the leak stops when the trigger is pulled.

The brass bushing for the trigger pin was pulled and the tiny o-ring and pin were both replaced with new items from his parts kit. Everything was lubed upon reassembly. No change - it leaks until the trigger is pulled, but it won’t cycle.

Anyone have any ideas for what we need to look at to get this leak fixed?

[Trbo323]

I know there's at least 2o rings in that one/off pin. It could be that you guys replaced the one that was towards the outside but missed the internal one

Replace both part 14 in the manual and I would also replace 31. If I remember right 31 can cause a leak associated with the trigger as well. Been a while since I've been inside one though

Sent from my motorola edge 2024 using Tapatalk

[lhamilton1807]

Thx, he’s confirmed both of the tiny o/rings have been replaced, the problem remains. I’ve asked about whether he rebuilt the drivetrain, including #31.

I also suggested that he write Tippmann to get pointers from them. Will report back with what we figure out, for posterity.

[FlightMedic938]

I know this is fairly old and you may have resolved the issue already but I’d like to add that a broken or missing piston guide in the regulator will present the same way as a bent trigger pin. It’ll make the gun leak down the barrel until the trigger is depressed but it won’t shoot.

I was experimenting with a different regulator spring and disc (Palmers) and it presented this way until I put the regulator piston guide back in.

[lhamilton1807]

Thank you! I haven’t had this on my bench for a while - he took it back home. Maybe I can get him over here for another attempt.

[lhamilton1807]

Piston guide is in place - thanks for the idea

[lhamilton1807]

Ok I finally got this on my bench again

I’ve replaced #28 on the back cap and in the valve body
I replaced #31 (spool bumper)
all three spool o-rings
top and bottom air transfer tube o-rings

Still leaking around the trigger group

I don’t have any 002 or 5-178 seals on hand to replace the valve pin o-rings or manifold seals. I’ll try those next.

[lhamilton1807]

Found 5-178 seals in his spares kit. The leak persists…

I guess the tiny 002 valve pin seal must be the problem

[lhamilton1807]

Thanks for all your help! I replaced the outer o-ring on the reg piston and the pin seat, which requires a 5/16 socket to get to. Also the spool spring.

Same
Bloody
Leak

I think I’m finally down to just the core/trigger pin seals. Which I don’t have 😂

I’ll put some in my next order for parts

[FlightMedic938]

Yeah it’s one of the valve core o rings then. It’s happened to me twice. First time I replaced them. Last time I put DOW 55 on them and a drop of silicone oil, Dye I think it was, in the trigger pin hole and it went away. Hasn’t come back since then.

[lhamilton1807]

Oh dow55 is a good idea. Maybe swelling them would fix it. I ordered more so if it doesn’t work, I’ll swap them out.

[lhamilton1807]

Finally figured this out. I thought the 002 orings were the issue, so I put in some BN seals and let them sit with dow55 for a few hours so they’d swell but no change.

Pulled out the engine and decided to inspect the 021 o-rings for defects. Turns out my buddy put one in that was a 019, stretching it so it wouldn’t seal. Replaced with the correct size and now she’s running fine.

[FlightMedic938]

Man that was a journey lol Glad you got it running again