With noisy pulleys[ car not been used in a while] i tend to carefully spray some duck oil onto the pulley making sure none hits the belt and this usually quietens things down. Noise will be a dry pump bearing, so keep an eye on it as the dryness can take a lump out off the bearing with usual problems associated with it. If it continues to make a noise, strip and replace/grease bearing.
HA HA HA.
Duck Oil is well known in the trade and should be available from a good car shop. Its a strong form of Solvent which i find better then WD40. Ive even used it on dry squeaky suspension bushes too and it works!!