I bought a 71 GMC 3500 and "going through" the mechanicals to make it safe etc. Wanted to replce the front flexible brake line hoses. It has disc brakes. Was told the flex line for that truck has been discontinued for years. Called Classic Parts to ask if the 3/4 Chevy line would fit and he said the GMC did not have the same braking systems as Chevy. The line is not leaking so I am not out of a truck. Any sugestions on who to call to see if any are avaialble in the aftermarket. If not, what then....change the spindle and related parts over to a later model?