The disclosure concerns cylinder barrels for piston pumps and motors which have lined cylinder bores. Each liner comprises a matrix of sintered, powdered iron which is impregnated with bronze, and which is metallurgically and mechanically bonded to the steel barrel. The liners are formed from porous, sintered iron sleeves which are placed in the bores in contact with bronze slugs. The assembly is heated in a non-oxidizing atmosphere to a temperature between 1,900*F and 2,000*F to melt the bronze and cause it to infiltrate the sintered preform and bond to the steel. Thereafter, the assembly is cooled in the non-oxidizing atmosphere to solidify the bronze, followed by air cooling to room temperature. Finally, the finished cylinder bores are machined in the bonded bronze-iron sleeves.