I have had my 74 Bronco for 3 days now, and my garage smells strong of gas fumes. I do have this mentioned canister installed, wonder if I need to see what is up with mine?
Hey Brent, welcome aboard! And an all too common problem unfortunately.
You definitely need to see what's up before you either spend so much time driving it that something gives up the ghost while you're at your farthest from home, or someone else at home as had enough!
Sounds like you'll be doing some crawling around and under the rig at first. Something everyone should do with a 40+ year old utility vehicle anyway.
Things that commonly leak on Broncos:
1. Aux gas tank like was mentioned. They're plastic and if abused or spent too much of it's time in cold weather, can crack.
2. Dual-tank selector valve by the driver's right heel. Good for many years, but an o-ring can finally leak. Starts with just fumes, but will eventually graduate into liquid.
3. Carburetor and air cleaner of course.
4. That tank behind the driver's seat can meet the same fate as the plastic aux tank. Split a seam. Usually about 10 years old, they start to vent. Sometimes they live forever, but not often. Happened to mine finally after about 18 years. Gooped it up good with slicone on top and been good since. Upgrading to the later non-tank version when it goes back together.
5. The plastic fuel lines from the main tank to the valve, then from the valve to the frame by the fuel pump. Some of them last forever, some get brittle with age.
6. Like any other vehicle, the hoses, plastic lines, sending units, breather hoses and vents, can all wear out with age. Along with changing the fluids then, checking for fuel leaks is a first deal priority.
Things to always do with a new-to-you Bronco then:
1. Change ALL fluids. Even if the PO said they did it, you can't believe how few actually change the gear oil in manual transmissions and differentials and transfer cases. Engine takes 6 quarts by the way, unless it's been changed out.
2. Check the steering linkage and front suspension components with "the test" that is written about here on the forums about a million times.
3. Check the brakes.
4. On that same note, check the rear wheel bearings.
This last bit about the bearings is because these are not a typical service item that people worry about. And they should.
They're a "lubed-for-life" product but nobody knows when to change them until after they fail. Which in most of our experiences here is roughly between 90 and 130 thousand miles, or 40 years.
So if the PO doesn't know, or knows for a fact that yours have never been changed, or you have more than 100k on them for sure, or you're just not sure, then I say change them.
When you look up the definition of "cheap insurance" a Bronco's rear wheel bearings are right at the top of the list. It's $100 or so well spent.
Sorry for the slight segué there Attac. Well, ok it was a full hijack. But fun stuff nevertheless.
Good luck and have fun!
Paul