Fuel and Cooling system issues

[broncosam]

Took my Bronco out for a while today, about 70 miles round trip. On the way home I stopped to re-fuel and noticed two things. The first was a minor coolant leak, the overflow bottle was puking out the cap. Second and the one that gives me the most concern, it was leaking gas underneath the vehicle at the point where the evap bottle is located behind the drive seat. Just a good steady drip. That's the first time it's done this.
My Bronco has a Dakota gauge cluster in it and according to it, the engine is not running hot, nor do I see or hear anything that makes me think it's overheating. After warm up the temp gauge will read about 190 degrees, and hold fairly steady at that point.
As for the fuel issue that one has me puzzled. I just have the factory rear tank, but it's all been replaced, new tank, sending unit, and all hoses. Any help would be appreciated. Thanks

 

[gr8scott]

Time to pull the cover behind the driver seat and inspect the fuel separator/evap bottle. Put your Bronco's info in your signature.

 

[DirtDonk]

Yep, even if it's filling with gas it should not leak out anywhere under there. Either the tank has a split in it (very common, but you'd smell it in the cab) or the lines are leaking. This last is not very common, but now that they're pushing middle age, things are failing more and more often than we've seen in a long time.

Paul

 

[broncosam]

Thanks guys, I'll pull that cover and check the evap tank for any splits or holes and the lines as well. I do have another of those tanks I picked up somewhere and have stashed in my garage. But I think the lines going to it have all been cut off about a foot from the tank. Another question, Is there any way to safely bypass that thing if it is bad, can it be eliminated from the fuel system?
How do I put my Bronco's info into my signature?

 

[gr8scott]

How do I put my Bronco's info into my signature?

At the top left, click on User CP. Select Edit Signature.

 

[DirtDonk]

Another question, Is there any way to safely bypass that thing if it is bad, can it be eliminated from the fuel system?

Yes it can, but it's not always a good result. The better method is to replace it with the newer version. It's not exactly "bypassing" it, but effectively that's what you're doing because the newer setup is simpler and eliminates the in-cab tank.

In '76 Ford went to a single tube run all the way to the new design charcoal canister mounted on the firewall.
I guess we should ask if your system is complete with original charcoal canister mounted up front on the passenger side frame rail just behind the front wheel? Just to be sure you're working with a full system.

What you do is replace that old low-mount design (hence the secondary high-mounted tank inside the cabin) with the later plastic vertically oriented high-mount charcoal canister up on the firewall. Then the plastic tank inside the cabin is not longer necessary and can be completely removed.

You cap off one of the vent lines in the main fuel tank, run the other one to a "Y" fitting, if you have an auxiliary fuel tank, or straight to the new charcoal canister if you only have one gas tank.
Then the fumes go straight to the charcoal canister and you plumb the two large ports on the canister similar to what you have now. One is just a vent to atmosphere and the other runs up to the air cleaner.

Done and done, with no excess fuel vapor to stink up the garage and the house.

Paul

 

[Jfryjfry]

If you’re not overheating, your cap is likely bad. There cheap and wear out so I’d just start with that

 

[broncosam]

If you’re not overheating, your cap is likely bad. There cheap and wear out so I’d just start with that

That's what I was thinking, but it never hurts to get another opinion. Thanks

Got under the Bronco earlier and no charcoal canister anywhere to be found. I did find a hose that is attached to a line that runs along the passenger side frame rail. I'm guessing that was hooked to the original charcoal canister.

 

[Rustytruck]

The whole point of the vapor bottle is to allow the fuel vapor from the gas tank to condense in the bottle and drain back to the fuel tank. that is why there is 2 vent lines on the tank. the vapor that is left in the bottle goes to the charcoal canister to be held in the charcoal. when you start your engine the vapor in the canister gets sucked into the carb to be burned in the engine.

 

[DirtDonk]

Since you no longer have one, just source a later model (late seventies to early nineties) canister from just about any Ford passenger car or truck. Maybe the other brands as well?
You just need the style with 2 large ports on the top and 1 small port, but most of them are going to have 2 large, 1 medium and 1 small and those are OK too. Any extra ports and you just cap them off.

Try to source the "mushroom" cap as well, for the one large port that is left open to breathe, but covered to keep debris and water out.
The high mounting position eliminates (or at least reduces) the necessity for the in-cab condensing tank.

Paul

 

[broncosam]

Okay , I pulled the cover that hides the evap/separator tank. I found no holes or evidence of a split anywhere on it. What I did find was that one of the lines from it has been plugged with just a bolt in the piece of hose to plug it. According to my Ford shop manual the one that is plugged should vent to the front aux. gas tank. My Bronco only has a rear tank on it. I'm going to the pick&pull this weekend to get a charcoal canister, there is one locally that has about 15 Ford Ranger trucks, surely one of them will still have it. I took a few pics to show what I found, my apology if they are to crappy to see anything. There is one last pic of another evap tank, that is the one I dug out of my small parts stash to use as a another reference.

 

[gr8scott]

The one that's plugged probably came from the auxiliary tank, which you no longer have.

 

[gr8scott]

Here's what your fuel/vapor separator looks like on the inside, pictures courtesy of member AZ73. Three of the nipples have tubes that extend
to the top of the bottle. One comes from the rear tank, one from the aux tank (yours is plugged) and the third one would have made its way to the
charcoal canister. The nipple without the tube returns fuel to the tank.

Here's a thread I started back in 2019 when I decided to get my evap system operational.

https://classicbroncos.com/forums/showthread.php?t=297095

EDIT: Helps if I upload the photos