Oiling Foot Pumps
Vintage pumps come with internal leather washers which need regular oiling to keep them supple and tight against the barrel to generate pumping pressure. There are various ways of oiling pumps - many have an oil hole or two in the barrel, some need oiling from the back of the piston. But oil you must!
Often you will find the insides of an old pump full of engine (mineral) oil and grease. These do allow the pump work for a time - but theres a problem! Mineral oil rots leather over time and stiffens it up - thus leading to cracking. To avoid this and give your leather washers and seals the maximum life, its best to use vegetable oil, cooking oil, olive oil or a similar non-mineral oil. A good option also is neatsfoot oil. When stealing the bottle of cooking oil from the kitchen, make sure to clear off all the greasy and dirty fingerprints before returning it. Maybe best to buy an extra bottle on the next shopping trip and keep it in the workshop to avoid problems?
Oiling is needed regularly - depending on use - but probably only once or twice a year at most. For old pumps that are found in the back of a garage and don't pump air - there are many possible causes. But the most usual is that they are completely dried out! Get some vegetable oil in and start pumping as the first experiment. It will
most likely start to pump air fine again - and even better after being left overnight. If this does not solve the problem, then something else is the matter - probably a rotted or damaged washer - or one that is inflexible, ripped or covered in mineral oil. Washer replacement is the best option here. But oiling can always be tried first. If its another problem, then at least you've oiled the pump - which it needed anyway!