Back in the late 60s just about any reasonably competent mechanic could grab tools and wing it on repairs. Emission controls were a little tricky but common sense and taking it one step at a time would get it done. Vehicles have gotten a lot more complicated. So much so that to work on one you really need a shop manual of some sort.

Time to buy the Haynes or Chilton manual for the make and model you own. Typically about $17 and well worth the cost for just the sort of predicament your facing. They are very handy and full of useful, vital, information. IMHO they should come with every vehicle. When I get a new, mostly used, vehicle I buy the Haynes manual as a matter of course.

If your interested in complete DIY overhauls and doing everything yourself it can be worth checking into buying the manufacturer's shop manual. Often several hundred dollars they usually go into most every possible procedure in great detail.

Whereas the Haynes manual is more about trotting down to the parts store to buy a new or rebuilt part the shop manual might show you how to rig a jig to re-manufacture the part yourself. The sort of thing that might be required in a third world country or remote area.