72 fuel system Question

[Dave S.]

I have a 72 ZQ3 car. For some unknown reason there is a hairline split in the return line on the passenger side rear near the gas tank. When the car is running the line is under pressure and gas is squirting from the split. Is it proper to have pressure in the return line or is there a malfunction in the check(?) valve at the top of the tank where the return line enters the top of the tank. ???? In any event the split needs to be repaired. What is the best type of repair to make. ???? Flared w/ a brass block or a plumbing style repair. ??? Any help and guidance is appreciated.

[Joe L.]

Re: 72 fuel system Question

Dave------

I doubt that there's a problem with the seperator mounted on the tank. However, if there is there's not much you could do about it----the seperator is plastic and non-repairable, it's been GM-discontinued for quite a few years, and it's not reproduced. Most of the used ones are probably not in much better shape than the one you have.

As far as repairing the return line leak goes, I think that I'd try an epoxy repair. First, roughen up the area well around the leak area with coarse emery cloth. Then, clean scrupulously with brake cleaner. Last, apply JB Weld to a generous area surrounding the leak and allow it to fully cure. I don't think that you'll have any more problems, whatsoever. If you do, then you can try one of the approaches that you mention. I really don't think that it will come to that.

JB Weld and most other similar epoxies are completely impervious to gasoline and other solvents. They will not degrade or fail over time (at least, any time period that's going to matter to you or I) as a result of the effect of gasoline contact.

[Patrick H.]

Re: 72 fuel system Question

Joe,

The JB Weld is a good thought. Dave and I had discussed other repairs for his car, but that one never came up. I doubt you'd need a very thick coating.

Do you think a thin coat of JB should extend all the way around the gas line? Would that keep the spot of epoxy from popping off? Just a thought.

By the way, Dave, I used JB Weld to fix two pinholes in Dad's 72 gas tank. Of course, I then used Eastwood's gas tank sealant kit (on the inside) to finalize, but I'd have to say that 5 years later it's still holding. Joe may be on to something.

Patrick

[Joe L.]

Re: 72 fuel system Question

Patrick-----

If the fuel line surface is properly prepared by roughing it up and cleaning it scrupulously, then I don't think that the "full circumferential" application of the epoxy will be necessary. However, I'd likely still do that just to make ME FEEL BETTER. If the JB Weld adheres like it's supposed to, it won't be "popping off". As Jack Lord used to occasionally say on Hawaii 5-0..."Bet on it, Dan-0"!

JB Weld and similar epoxies have been used for years to replace and/or seal the "spun-in" fuel bowl plugs on Rochester Q-Jets (all of the bottom plugs, 2 large and 2 small, PLUS the large front plug on the front of the inlet fitting on Chevrolet Q-Jets). If the application is done properly, those plugs will NEVER leak again.

[Dave S.]

Re: 72 fuel system Question

Joe/Patrick,
Thanks for the comments. I will give it a try and report back. This pinhole seems to have a exterior manufacturing defect on the line so I think I'll do the repair around the entire circumference, just to be sure. I've never seen a defective steel line but due to the limited usage of the car and its protected location I have no other explanation.

[Dave S.]

Re: 72 fuel system Question

Joe,

I tried the JB Weld fix and it worked perfectly. Coated the line around the circumference for about 1 1/2" in length and the leak is gone. Thanks for saving me a complicated repair.

[Patrick H.]

Re: 72 fuel system Question

Dave,

Sounds great!

If you get a chance, I'd still like a pic of the area. And I promise not to show it to any judges!

Patrick

[Dave S.]

Re: 72 fuel system Question

Patrick,
I replaced the line clamps and you can hardly see it. A photo would be impossible. I can explain it better in words if you want.

[Patrick H.]

Re: 72 fuel system Question

Just send me a schedule of when it is getting shown, and I'll come look. Or, at Windsor, show me on my car.

Which car of yours is going to Windsor?

Patrick