On 07/04/2014 14:45, newshound wrote:
On 07/04/2014 14:33, Another John wrote:
We have an old banger for running around in, and I need to use my foot
pump more than I'd like on its rather old and rusty wheels.

Lately my pump *seems* (could be wrong) to have become less effective,
i.e. I seem to need more pumps per PSI injected.

Is there any kind of maintenance I could do on the pump? The cylinder
is welded closed, but I wondered what might happen if I (for example)
sprayed WD40 into it via the air intakes. For example would it
revitalise the valve in there? Obviously I could try it, but
maybe someone here has tried it before, and can advise Yes or No!

Cheers
J.

In the good old days these were very robustly made and could be
maintained. The main seal was greased leather. IME modern pumps are more
flimsy and it is usually the hose which gives out first, typically
leaking at the crimped joints.

If you are *sure* the hose is OK (leak test with soapy water spray?) it
could be the main piston seal. WD40 might let you do a quick check as
you describe but someone will be along in a minute telling you that
mineral oils are bad for rubber tyres. Silicone oil (as used for
lubricating plumbing fittings) would be OK, but not cheap.

You might find that one of those little electric pumps which you can
sometimes pick up for a fiver with a tank of petrol will meet your needs.

I bought one of those pumps which you plug into the cigarette lighter
socket, and its great, with no effort required to pump up the tyres.