pump head leaks on presta valves

Ive got a serfas fmp-500 floor pump, which is built like a truck and
pumps very well. I use it on my schraeder valves, and everything is
great. But when I put the pump head on a presta valve, it leaks even
if I detach/reattach several times. I called Serfas, and to their
credit they shipped me a replacement head that day. but the new head
has the same behavior...

Anyone have any ideas on this? replace the head? Oil the head or
something?

thanks,

Dan

wrote:
Ive got a serfas fmp-500 floor pump, which is built like a truck and
pumps very well. I use it on my schraeder valves, and everything is
great. But when I put the pump head on a presta valve, it leaks even
if I detach/reattach several times. I called Serfas, and to their
credit they shipped me a replacement head that day. but the new head
has the same behavior...

Anyone have any ideas on this? replace the head? Oil the head or
something?

I would try degreasing the washer (seal) in the head and the valves on the
bikes, or try a different washer if I had one that fitted. Failng that, I'd
get a better head, eg. Topeak SmartHead.

~PB

On Sat, 4 Oct 2008 15:00:41 +0200, Pete Biggs wrote:

wrote:
Ive got a serfas fmp-500 floor pump, which is built like a truck and
pumps very well. I use it on my schraeder valves, and everything is
great. But when I put the pump head on a presta valve, it leaks even
if I detach/reattach several times. I called Serfas, and to their
credit they shipped me a replacement head that day. but the new head
has the same behavior...

Anyone have any ideas on this? replace the head? Oil the head or
something?

I would try degreasing the washer (seal) in the head and the valves on the
bikes, or try a different washer if I had one that fitted. Failng that, I'd
get a better head, eg. Topeak SmartHead.

~PB

(original post from "zarfus" never got here as everything from gmail is
filtered)

Most pump-heads have a replaceable sealing bung. This need a different
size hole for presta vs. schraeder. Check that you have the correct bung.
You may be able to compress the bung with the threaded cap that keeps it in
the pump-head, and reduce the size of the hole.