PCP pump not working

[CiklaMan]

Hello!

I have a chinese pcp pump, I ordered it from aliexpress.

When I try to pump air the pump makes just a little bit pressure. When I pull it down it always come back, like a spring.

Any idea?

Thanks!

 

[nervoustrig]

If it pushes back up on it’s own, it’s likely to be the check valve.

If it draws back down on its own, it’s likely to be the final stage O-ring.

 

[MrP]

Likely just needs a good cleaning. But I'm not good at diagnosing whether it's an o ring or something else. I have fixed three pumps that do what you are doing by removing the base from the tube, cleaning that base all out. Then unscrew the little valve assembly at the bottom end of the tube - a spring and valve will come out (so LOOK CLOSELY so you know how to reassemble). Clean all the gunk out of there. It's very very easy to do and for me at least worked wonders. It hasn't turned out to be any of the O-rings or any of those other types of things yet just cleaning out that base.


and don't forget to lubricate n

 

[CiklaMan]

I changed the o-ring and the spring on the check valve. Didn't work.

 

[CiklaMan]

I cleaned it, I did everything I could. But nothing change. The pressure is still very low and it's goes up every time. 

 

[Guest]

 I've got a good diagnosing song for you:

https://youtu.be/PqUenEMwsdQ

On a more serious note: have you seen if anyone is doing rebuilds on youtube with that model or something similar?

One thing I like about the Hillpumps is how fixable they are. Comes with a price tag, but so does your time. Chinese pumps are cheap. You could toss it and buy the Walmart one and get the warranty and return it when it breaks.

 

[MrP]

information from my air Venturi manual the only one that has some kind of a troubleshooting guide

 

[Aimright]

I have had to rebuild mine a couple times, The first time I wasn’t sure as nothing appeared out of order, so I replaced most everything, all orings and the check valve. The second time I think it was my check valve, specifically the little rubber ball, but I think I replaced an oring or two that time also. For the second time I purchased a parts kit from Aliexpress: https://www.aliexpress.com/item/4000848362033.html?spm=a2g0o.productlist.0.0.70fc2e17byj58c&algo_pvid=664c2106-46ca-4acd-9d10-23b05bf505a3&algo_expid=664c2106-46ca-4acd-9d10-23b05bf505a3-0&btsid=0bb0624316118544730792669e53ab&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

Don’t use it much now I have an scba tank, but I still take it with me just in case....