New Gas Tank: What Sealer/Coating Do I Use to Keep it Looking New?

I think so.

For instance, are you suggesting that the float could 'hang' lower outside the tank (giving a proper reading of 'Empty'), but when installed, may be hitting the bottom of the tank, not being allowed to 'hang' to its fullest extent?

Or, are you suggesting that it's the upper range of travel that's out of whack?

Thanks

 

I understand. However, it seems futile, and time consuming, to run the tank dry, disassemble everything, then try blindly bending the existing float arm in some direction, hoping for a fix.

Shouldn't I just toss this current funky sender and start fresh with a new (single or dual tube) sender? If so, besides reading the new sender with a meter, and manually raising and lowering the float while watching the fuel gauge go from 'Empty to Full', is there anything else you would suggest I do prior to installation?

I actually have a new Year One dual-tube sender ready to go, if that's what you suggest.

Thanks

 

Here's some background info, that while probably not relevant, I'm going to mention anyway.

When I bought the car 6 years ago, I put in a new Year One tank (part #AR89), and reused the original single tube sender. Everything went right in, worked just fine, I never gave it a second thought.

Recently, I was jacking up the car by the differential with a floor jack. While doing so, I carelessly forgot to chock the front wheel. With the jack fully extended, and both rear wheels off the ground, the car began to roll and the jack slipped off the differential and the car came crashing down, with the jack pad crushing the center of the gas tank.

While the center of the tank was clearly caved in, it did not rupture or leak. While waiting for a replacement tank & sender to arrive, I continued to drive the car, with no issues.

While driving in this damaged state, the fuel gauge properly dropped to empty, as it should. When I went to fill up, I then noticed that the gauge would not read past half full, and I could not pump a full 20 gallons into the tank. Presumably, because its volume was now significantly reduced due to the damage.

I know I'm really reaching here, but this event could not somehow have damaged the fuel gauge in the dash, could it?

I can't imagine this info would have any bearing on the issue I'm now having with my new identical Year One tank (AR89) and the new sender, would it?

Thanks

 

I understand how to test the sender outside of the tank. But how can I possibly test the senders range of travel while it's installed in the tank?

Thanks

 

1) Sender/fuel gauge on dash operates properly outside of the tank. Full range from 'Empty to Full'.

2) When tank is filled to capacity (20 gallons), gauge will not read past half full.

3) When gauge reads empty, there is still ~ 8 gallons of fuel in the tank. I'd say that's considerably more than what would be considered a 'reserve'.

When I imagine all the possibilities, and given the above info, I can't decide if the sender is electronically deficient (wont give 90 Ohms or send proper info to fuel gauge), or mechanically deficient (float rod not bent correctly, etc).

What are your thoughts?

Thanks

 

No, I understand everything you've explained, thank you.

Given the info you've been given, I was just wondering if you are able to take an educated guess as to whether the sender is electronically or mechanically deficient.

If you can't offer any more advice without me first removing the sender, it's OK, I understand.

If you're able to tell me how to drain 20 gallons of gas from the tank (besides driving the car), I'll go do that right now.

Until then, I'm afraid it's going to take me a couple days of driving before I can offer any more data.

Thanks

 

It's my understanding that cars '71 and forward can not be siphoned because of some sort of filler restriction/baffle in the tank.

Regardless, I'm anxious to get this resolved. I'll drain the fuel from the pump right now.

Thanks

 

Just tried disconnecting the line at the fuel pump. The gas would not freely flow out. Tried raising the rear wheels 8 inches off the ground, again no luck. Just a dribble.

Tried siphoning. No luck there, either ( wasn't expecting any).

A full tank is too heavy for me to drop by myself. Looks like I need to go for a long ride.

Thanks

 

Once the tank is down again take a ruler & measure the depth of the tank from the sender hole. As an example say it's 10 inches. Let the float hang outside & measure from the lip of the sender to the bottom of the float. It should be about 10". With the float in the all the way up position the float should NOT be above the sender. If it is bend it down so it's level with the top lip of the sender. This is what it sounds like to me. Since I deal with lots of even older cars I have to double check EVERYTHING!!!! You can't just ASSUME everything is as it should be even when the unit has been sent out for a rebuild. You've got to check EVERYTHING!!!!!
Just my thoughts on the subject.


Tom T.

 

Brilliant suggestion, Tom. I'll do just that.

Thanks

 

Aside from doing it the old fashioned way and using my mouth, any suggestion on how I can get the fuel to start flowing?

Thanks

 

Drained the tank, pulled everything apart (again), and found the problem.

First, I siphoned the 20 gallons using this method: https://www.youtube.com/watch?v=xpHqraOdMDs. Only, instead of using my mouth, I used my compressor. This worked flawlessly.

I then compared the single tube '68-'70 sender (that was only reading up to a half tank) with the dual tube '71-'72 sender that I had on hand.


As you can see, when installed, the '68-'70 sender has its float pointing toward the left/drivers side of the car, while the '71-'72 Sender orients toward the right/passenger side.

When I peeked into the tank, I could see what appeared to be an extension of the filler spout, or some type of baffle, located on the left side of the tank.

Clearly, this spout/baffle was restricting the single tube '68-'70 float from its full range of travel.

I installed the dual tube '71-'72 sender, and all is well.

It should be noted that the original sender ('71) was a single tube, but its float was directed toward the right side of the car.

Here's a shot of my new tank, with a copy of the original build sheet, prior to intallation


I wish to thank everyone who participated in this thread, and encouraged me to see this repair to the end.

I hope these pics may be of some value to someone in the future.