more gas tank questions....

[Marty Rogan]

Victor,

How much does Gas Tank Renu charge to clean and seal a tank? And does that include removal and reinstall.

I was thinking of having that done to my early like the sounds of trying to drain a gas tank in my garage.

Marty

[26th-Z]

http://www.popularmechanics.com/automotive/car_care/1998/10/Gas_Tank_Restoration/index.phtml

The POR suggestion is for you do-it-yourselfer's. Motorcycle shops deal with this issue all the time and a good ole radiator repair shop may help you also.

[kmack]

I agree with Victor about the Gas Tank Renu. I have had my tank done. And am having little rust issues clogging my fuel filter. Gas Tank Renu is taking my tank back and repairing it. They are definitely good for the warranty.

As for price, they charged me $150 back in '94 to clean and seal the inside and outside of the tank. That does not include removal or re-installation.

Bentley,

1) There should be a vent line attached to the top section of the tank that vents back to the expansion tank inside the right rear quarter of the car. If you can not get the tank filled (or the air bubble out) then the line is clogged or kinked, thus not allowing air to vent out.

2) I doubt the "crud" came from the vapor return lines. Over time, the "light ends" of gasoline will evaporate leaving the "heavy ends" behind. If enough of the light parts of gas leave, then what is left is this sludge. You'll notice that gas, left over a period of time (usually 5-6 months or more), will become "thicker" than before. Evaporation is what causes the sludge in the tank, the carbs, the fuel lines, etc... Btw, I used to work for a research facility that made and tested experimental fuels. That's how I know about this stuff.

3,4,5) By all means avoid using muratic acid at all costs! Use a specific tank cleaning kit or some sort of solvent. Acids will just cause you headaches later in life. I learned the hard way.

As for the sending unit, it can be cleaned up with solvents and a good cleaning brush. Just make sure you don't break any of the wires on the "rheostat" portion of the unit. It all looks intact, then use it over again. I'm not sure if replacements are available.

[LanceM]

Since your tank sounds many times worse than mine was I would for sure recommend it be take to a professional, it sure sounds like more than a home job.

The float sending unit comes out in one piece and should be removed and cleaned up. Take care taking it out, there is a metal ring that you will have to drive counter clockwise and get out then the whole sending unit can be removed. Take care removing the ring, as far as I know there are no replacements, the little tabs that you pound against (gently) can be broken off and you are screwed....

I cleaned up my sending unit as I have not been able to find a replacement, if anyone knows where new replacements are available let me know as I'd sure like to put a new one in. As was mentioned before don't break the little wires on the rheostat or you are screwed again!!!

[Bentley]

Thanks for all the help!

I appreciate the explaination about the "heavy" end of the gas spectrum. How can something as simple as an empty metal can......get so complex?

My tank appears to have no visible rust, but an ungodly amount of crud. After it flakes off, Between my fingers, the crud appears mostly like plain old dirt. However, I have considered the idea that it is a new chemical element all to itself, or perhaps a gas tank inhabiting life form since it is as heavy on the top of the tank as the bottom. This crap is a good 1/8-1/4 inch thick, and is, in places, impervious to an hour of steaming hot pressure from a power washer. Strong detergent and degreaser have little/ no effect on dissolving it. It is possible that I have a tank that someone else tried to seal and did a poor job. I wanted to believe this, but once the stuff comes off in a hunk, it can be easily smashed into dirt between my fingers.

For the record.......these tanks have two baffles, about 5-6 inches in height, dividing the lower half of the tank into thirds. At the bottom of each baffle are small gaps and at the top of the baffles there is a couple of inches of clearance. So they are like fins sticking up 80% of the depth. I have found that I have been able to get most of the crud (80%) out of the section nearest the input tube and sending unit, because I can blast away with straight access. I have cut back the crud to reveal clean metal, and have opened up the gaps at the base of the first baffle, allowing the first and second section to again be one tank, instead of two.

Thought...It makes sense this crap would not be broken down with detergent, since gas would cut it away naturally if that were the case. Perhaps kmack knows what will break down the mystery substance?

New QUESTION:

Since this crud is not Rust-based, but appears to be heavy residue, it seems that cleaning the tank is a must, but that having the tank heavily sealed does not directly effect the core problem. If kmack has explained the nature of the crud, then it will appear again on top of any sealed surface. Right? (Or perhaps only if left for decade.)

If at the end of this weekend, if I have not solved this puzzle, I'll send it off.

Z Village Idiot:stupid:

Bentley

[kmack]

I would take the tank to a radiator/gas tank shop. There are some fairly heavy-duty chenicals out there that can tackle just about any type of "crud" (I like the use of that word, btw!), but most will be of industrial strength and hard to get your "regular consumer's" hands on. Plus you really wouldn't want to get some of this stuff on your bare skin anyway.

Let a professional do the work of cleaning it. They could also give you a pretty good idea of exactly what the crud is. They most likely have seen it all. The cost of a cleaning can't be much more than what you've already spent in your time so far.

[Al Squillante]

LanceM

I ordered the sender ,O-ring and clamp from my local dealer. Cost was $42 for all.(1971 Z)

Al S

[mdbrandy]

Talk to Chloe at Midwest Z.

[Daniel]

I'm with kmack.Let the pro's do the tank and you'll never touch it again.I had a friend that the por15 stuff made a blister bubble in the tank.It of course waited to pop.It coated his fuel system and carbs.NOT GOOD!!I believe do it right and move on to something else.

[tanny]

I began with a tankfull of crud that had sat for twenty years in storage. As Daniel describes in a previous response, I put clean cracked gravel in my tank along with acetone and laquer thinner and rotated the tank all around by hand. The tank was silver shiny afterwards. Of course, after the fact, I got to thinking that it isn't very hard to create a spark by hitting rocks together or hitting rocks against metal. I think the rocks were in my head. I don't think I would try that method again. Word of warning from Victor.

[Victor Laury]

Originally posted by LanceM

I cleaned up my sending unit as I have not been able to find a replacement, if anyone knows where new replacements are available let me know as I'd sure like to put a new one in. As was mentioned before don't break the little wires on the rheostat or you are screwed again!!!

Check again with our vendors. Within the last year, I've been able to purchase from Nissan a new sender for my Z, my 70 roadster and my 1965 320 pickup! So I find it hard to believe that there should be any trouble for you.

[abas]

Does anyone have any idea how to remove dents in a fuel tank?

The previous owner of my 1970 z decided that the middle of the fuel tank was a good jacking point for the rear of the car:stupid:

A friend of a friend thought I could 'blow' the dent out with compressed air, but I'm doubtful I could get enough pressure to do so without something breaking first.

thanks for any help