Subject: Ki-Gass pump repair
The Ki-Gass pump on my 2ltr was not working properly anymore. First I asked aerovintagespares.com for a service kit but they only seem to sell complete pumps (good copy of the original but at 399 GBP)
I removed my pump and opened it from the back side (the two fittings where the tubing is attached). In each one you have asmall spring and metall ball acting as valves, pay attention to the different directions.
One of the springs was a bad replacement and rusty, the balls also had a bit rough surfaces. I ordered standard stainless steel springs from a company febrotec.de (0X-RDF1187 cost 2.60 EUR a piece, you certainly find other spring manufacturers in your country). The closest standard dimension was 4mm outer diameter, 11mm long and 0.3mm wire thickness. (Even better might be 4mm OD, 12 or 13 mm long and a bit thinner wire). New balls (4mm diameter) I took from a bycicle ball bearing.
It works much better now.