Need advice on FX hand pump lube

[smudger1234]

More help needed thanks.
Despite being stripped down, cleaned, then carefully reassembled, the pump will only attain 150bar.
All manner of O ring grades have been tried to no avail. So now we are back to original spec with no change in behaviour of the pump.
Would we be correct in assuming that 150bar is the 2nd stage limit and the problem could exist somewhere in the final stage? But where, why?
Has anyone had similar results and what was the solution?

It is driving Jeff crazy; I'm Ok as I am there already

I would check the final stage seal. This is the one most people substitute out for a cheaper commonly available o ring, needs to be the original PU spec; nitrile and viton dont cut it.

[slow_runner]

I would check the final stage seal. This is the one most people substitute out for a cheaper commonly available o ring, needs to be the original PU spec; nitrile and viton dont cut it.

Thanks for the advice smudger.
All the seals are as per the FX recommendation; the final stage seal is PUR90 grade.
In that regard our local supplier, Seal House, have been very accommodating with advice and service.

[angrybear]

How are you testing the pressure ? have you blanked it with a brass plug or are you trying it on a rifle ?

Could it be that the adaptor is leaking rather than the pump ?

[slow_runner]

How are you testing the pressure ? have you blanked it with a brass plug or are you trying it on a rifle ? Could it be that the adaptor is leaking rather than the pump ?

Hi angrybear.
I received a call from Jeff late last afternoon, he had a big smile in his voice
After isolating stages he discovered that a gland seal was passing. He has sorted that by resorting to using 3(?) smaller O rings.
I will know more when I visit next and I'll post images if possible.
He tells me that it now pumps up quite efficiently.
So much so that while pumping up his pneumatic air rifle, the old hose couldn't take it and blew out in protest

[slow_runner]

After isolating stages he discovered that a gland seal was passing. He has sorted that by resorting to using 3(?) smaller O rings.

This is an early FX 3 stage pump and is a bit different to the available drawing.
http://www.fxairguns.com/wp-content/...d-partlist.pdf
The second / third stage piston (#11) has two internal O ring seals that it appears weren't up to it; there was enough room for another to be fitted to the stack and this seems to have done the trick.
Job done.
Thanks for all your suggestions

[Ruger Red]

Red rubber grease would be my suggestion. Cheap and a tub would last a couple of lifetimes.

[slow_runner]

Red rubber grease would be my suggestion. Cheap and a tub would last a couple of lifetimes.

There is a good idea Red, thanks.

A couple of lifetimes eh? The exit door is over the horizon so a sachet or two should last me well enough.
Time to visit the local brake shop and see my mate about some spare floating sachets

[greenman]

Don't use normal white silicon grease...I used some abbey and after a while it started to combust.Don't worry you will notice the smell. Upon striping the pump ,burnt grease and fried seals.
The only product I found that didn't was the stuff that hills sell .
As for three in one oil ..... seriously????

[Neil54]

When cleaning model aircraft engines, they would fire and run on WD40, also 3in1 I seem to remember.
Models use caster oil as a lubricant. I wouldn't put it in your pump though, dries to a sticky mess.

Lubricate with silicon based products.

[keithy]

If you read the info on the 3 in 1 container it says; contains petroleum distillates don't use near heat, from memory I remember my BSA meteor giving a loud crack if I put 3 in 1 down the transfer port. I definitely wouldnt use 3 in 1 in a pump pumping at 200 bar (3200 psi).

[greenman]

Nope....even the very benign looking abbey white silicone grease combusted ...like I said,the hills grease is spot on and the tub will last a lifetime.

[evert]

I bring up this old thread, as I just found a possible source of the mysterious FX-recommended grease for PCP pump lubrication, Fuchs Renolit RHF1:

https://www..de/itm/Fuchs-Renolit-RH...-/112402374510

[bighit]

I came upon this 'SuperLube Synthetic Grease' http://www.guncity.com/superlube-syn...-85-gr.-117304

We're giving it a bash. Certainly the pumping effort has been reduced markedly so we will see how it performs over the long term.


The debate about mineral oils (fuel), high pressure/temperature, oxygen/air ratios would seem to be deserving of a thread on its own?

We used that lube for diesel driven compressors. No problem with it. I still have some in my toolbox.