Please check your fuel hoses before adding fuel to your tanks.
I want to bring this up to make you aware of defective reproduction hose assemblies from a manufacturer of the replacement for GM part# 3735951. This is the 3/8 sized hose for the 3/8" sized hard line from the tank. Various vendors use their own numbering system so look up your own vendors number for reference.
Note: This is not a vendor bashing exercise. It is a warning to purchasers, suppliers and installers. The vendor has been made aware of the problem and I'm certain it will be corrected quickly. They had a different problem many years ago with this part, posted a recall on their site and corrected it.
One thing I'm uncomfortable with is why this simple hose assembly continues to have problems. A simple Quality Control test should be done on each one in the future to avoid this issue. See my test below.
Hose assemblies:
Top is NOS, middle is my original, bottom is the defective reproduction hose(s). I use plural because this is not a isolated case.
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These reproduction hoses have a female brass end with a inverted flare, internally threaded to accept the 3/8" male flare fitting from the hard line. When attempting to tighten the hard line fitting from tank it will not seal properly. You may think it's sealed, but it is not. It will leak fuel. The problem is that the female brass inverted flare fitting has not been threaded properly. The threads are not deep enough into the fitting. The flared tubing of the hard line will not seal with it's mating inverted flare of the brass fitting.
Here is th comparison....
Upper is the defective hose. The threads are not cut deep enough.
Lower is my original, which has been leak free for 62 years(next month).
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This is what happened to my hard line fitting after repeated attempts to stop the leak. I ended up using my air hose set at 5PSI to blow the fuel back to the tank to stop the siphoning. I added a cap and clamp as added safety until a good hose would arrive.
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I wanted to replace the existing original hose as it felt spongy. I struggled with this new hose. Continued attempts to tighten it while listening to loud squeaking sounds did not help. A year ago I read of the identical problem someone had in Europe. The problem was fixed shortly afterward but now has returned, or it is possible old stock was mistakenly resent to some of the vendors.
Test fit your fittings before replacing it on you car. If you have a restoration underway and have installed one of these defective hoses you will have a major leak when you first start the engine after adding fuel to your tank. The fuel will not arrive at this hose until the engine is cranked for startup as the fuel pump draws fuel from the tank. Once this happens, the siphoning action will take over and you could have a serious leak.
This was after extreme tightening, and before getting a fuel bath down my arms when I removed it. You may smell the fuel while watching.
Here is one comparing my original hose to the defective hose using a 3/8" male flare test fitting.
It has been determined that one of the larger suppliers located in Michigan is the supplier of this hose assembly for many other vendors. My vendor in Virginia checked all of the hoses in their stock by test fitting with a common 3/8" flare fitting, as I showed below. They all failed to tighten and were removed from stock.
I was able to locate a replacement hose form another supplier here in Florida, Pronesti Classics. Gary sent me one right away which I received today. It is made in Tampa by a different manufacturer. It passed my bench test flawlessly and will be installed during my next visit to the car.
Made in Tampa. Both early 5/16" and 3/8" hose assemblies are available from Gary.
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Deep threads
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Here you can see the proper depth of the test fitting.
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Again, a simple 10 minute job has now taken about a week or so
.Rich
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