well i think what you mean is the chrome cylinder rod not the piston as these are rarely chromed and you cant see the piston till you disasemble it anyhow. as for repair options i would first price a rod from the dealer, sometimes they arnt too bad, and sometimes they are outa this world expensive like the 12 inch long 25 mm dia rod for my john deere steering that deere wanted 460 bucks for! if a rod is a bit high in price then call around to a few hydraulic shops and see what they want to make a rod for it, usualy this is a much more reasonable option. or if you are a do it yourself kinda guy you can simply buy the chrome stock from a hyd shop or mcmaster carr and make your own rod. rods can be rechromed also, but this is usualy only cost effective on large cylinder rods. the other option if its a small chip is to polish the edges and put in a seal kit and use it as is, often a ok solution if its a limited usage machine not an every day construction rig etc. as long as its well polished the seal wont be damaged and will just leak a little when it goes past that point, but very minute amount if any realy