Gas dripping at rear after fill-up

[mally002]

I just filled the tank on the 240 and noticed gas was dripping from the rear. After inspection it appears to be running down a black hose that is located almost at the far rear. If you look up from the ground it is behind the tank, nearer the taillight(right side).

Any ideas why at half a tank it doesnt leak, but full it's dripping?

Thanks,

[ddezso]

Mine does the same thing. I think it's probably a cracked or partially disconnected filler hose. My fix so far is to never fill it up. That is a lame fix but all I can do until I can drop the tank and fix it properly..

[e_racer1999]

Mine does the same thing. I think it's probably a cracked or partially disconnected filler hose. My fix so far is to never fill it up. That is a lame fix but all I can do until I can drop the tank and fix it properly..

haha... that's the fix i did with my other 72 that i no longer have. i got a filler tube and never put it in.

[MikeW]

It may be the filler hose as suggested but it may also be some of the other vent hoses.

[mally002]

Thanks for the info, I think you guys are right. After I ran some gas out it completly stopped....so I'm taking your advice and never filling up.

[Arne]

Better to find the leak and repair it.

[jmortensen]

It could be the filler, any of the vents, or the sender. It shouldn't be hard to chase down a leak in a Z tank, but I fought with one for a couple years off and on. Now I'm convinced that tank was leaking from the seam between top and bottom, no matter anymore, going fuel cell now...

[e_racer1999]

couldn't it also be an actual hole in the tank?

[TomoHawk]

You could probably do yourself a big favour, and get your tank cleaned & seled. then you'll find the leak, and have a perfetly rust-free gas tank with all new (and safe!) fuel hoses. The downside of this is that it may be expensive. Eventually, it will need to be done.

[a7dz]

After rereading this post I would have to say the most likely candidate is the vent hose on the top side of the tank which just happens to be the one with fuel on it when full. Located on the right side of the car. That would be the first place I went.

When the seams leak the fuel doesn't normally follow a hose to the low point it could but, not as likely as the hose leaking it self.

[JimmyZ]

Hopefully it is as simple as a rotted soft line. My tank had one of the vent tube leaded joints crack. Couldn't fill it up beyond half until I cleaned it and applied copious amounts of JB weld. This sealed it for quite a while. Amazing stuff that JB weld.

While my Z was in a million pieces during resto I cleaned the tank and cut an access hole for sandblasting. (After completely removing any chance of fuel or vapors being present) Had the local radiator shop resweat all of my vent lines and filler neck. By now the inside of your tank probably has a decent amount of rust anyway. The tenacity of the rust was so great I had to sandblast and Ospho twice to get it all out. Look into getting RedKote liner if you decide to clean/line the tank. It is removable with MEK and fills pinholes well. The guy at my local radiator repair shop showed me a slew of tanks that had been sealed with other products. Renu's process and service is the best with proper prep/RedKote coming in second place according to the rad shop.

Please be extra careful with raw fuel or vapors. I sustained second and third degree burns over 50% of my body years ago... All from half a cup of gas. It ignited twelve feet away from me! (Had a lawn service) Cutting and scrubbing off your skin for a month is no fun!

My 2c

Jim

[geezer]

I once got a great tip from a bike builder. He used a product from the Maytag people, used to remove rust from dishwashers and such. Labeled "for professional use only", and for good reason. The fumes can cause serious lung damage. That didn't deter me, I used it in a gas tank, with about 10% black diamond sand mixed in, as he instructed, sloshing around for a few days in my spare time. The results were astounding, shiny as a new silver dollar.

[beandip]

I just filled the tank on the 240 and noticed gas was dripping from the rear. After inspection it appears to be running down a black hose that is located almost at the far rear. If you look up from the ground it is behind the tank, nearer the taillight(right side).

Any ideas why at half a tank it doesnt leak, but full it's dripping?

Thanks,

If the leak is dripping from a hose in the rear of the tank as you said . This is a vent line . However this vent line connects to the tank near the top . There is another vent line that is connects to the lower section of the tank, in the back also . This one is on the driver side across from the muffler. If you replace these hoses be sure to use gasoline rated hose. Nappa carries 5/8'' hose that is for gasoline. Under NO CIRCUMSTANCES APPLY FLAME TO YOUR FUEL TANK. Using exhaust gasses from a engine and then using a torch to solder is asking for and explosion. and you will make he news at 11:00 . JB Weld is not effected by gasoline by the way . I have seen DRY ICE USED TO PURGE FUEL TANKS and it works. But it still is a gamble if you don't know what your doing. I personally have seen and dealt with the results of people trying all sorts of methods of purging gas tanks . As a Fireman assigned to rescue and engine companies in LA . A couple of guys saw God doing this. Tommo WHAT THE HELL ARE YOU THINKING ! I have a drawing of the tank and venting system showing all the lines. PM me if I can be of help . Gary

[1 Bravo 6]

Send a prayer of thanks to all the Gods that mankind has ever worshipped since the beginning of time that we have members like Gary,(Beandip), and Escanlon, who KNOW WHAT THEY'RE TALKING ABOUT !!!!!!

That could have been disasterous !!!.

Rick.

[Victor Laury]

I've worked in the underground tank field for the last 25 years. We dry ice tanks that even after triple rinsing, even after they've been open to the environment for years! Too many people have been killed, all of them knew for sure that, "There can't be any gas fumes in that tank by now".

Dry ice or nitrogen flush, no hot work is done to anything in ambient air.

[V8-240Z]

This is beginning to sound like a wood working forum I used to belong to where a member wanted to know if sucking vapors out on a paint can with a straw before it was sealed up was dangerous. Can we say drain bamage oh I meant to say brain damage.

[a7dz]

There a several good products used to clean and seal gas tanks, none of them use heat of any kind. I too have worked in aircraft fuel cells for over thirty years and I agree with Victor above. We will not even open a tank for entry until it has been purged with nitrogen for at least 72 hours, and then only after we have MEL and LEL levels that are safe for entry.

The sad thing about this post is there is probably nothing wrong with his gas tank except some old leaky hoses. We have had a member put everybody’s life at risk who does not know better on pure uneducated speculation.

I suggest that one of the administrators go back and delete all posts in this thread that put our members lives at risk.

FWIW

[TomoHawk]

The reason things smell like gasoline after many years is because of some of the components of gasoline that are especially "smelly." They act like a kind of oil, or a sludge. In the lab, they drive the analytical instruments crazy, so you have to dilute the samples to get it to go through. The same components will pretty much soak into the metal and it's really hard to get rid of them, and even in minute amounts, you can still smell them.

Albeit, you should be very careful of gasoline vapors; they are what makes you car's engine "fire up" after all.

This stuff I've learned after working for years in an EPA lab, analyzing dirt contaminated (or not) with gasoline from storage tanks.

thx

[TomoHawk]

The discussion evolved, Stephen. Maybe Victory didn't advocate a certain technique for purging, but he did share his experience that hopefully, was successful for him.

[sblake01]

The discussion only 'evolved' after you (post 9) took it in that direction. You can answer me if you wish, but I am done here.

[ddezso]

As you can see from my post (#2) I have the same issue. As the son of a 35 year Seattle firefighter I too am super concerned with safety as we all should be.

My original plan was to drop the tank and do the POR-15 routine described in a wonderful do it yourself article on the site. I am now reconsidering that.

I have searched for fuel cell threads and didnt find anything. My questions are:

1) Any advice on where to go for a replacement fuel cell and any perspective on the cost?

2) Are there any decent sources for nice original replacement tanks so I can get a sound replacement that is original (and redo all of the hoses, etc)? I cant find any tanks for sale through my normal sources.

Thanks,
Derek

[Darrel]

7' of the 5/8" fuel rated hose for the vent hose that is on the driver side on the lower portion of the tank.

After 14 yrs of sitting, the one in my 240 leaked like a sieve after filling it up. You don't have to drop the tank to replace this hose. You will have to get to the expansion tank inside the pass side to replace it at that end.

[MAX]

I too have had the same problem with a fuel leak after filling the tank. My leak turned out to be the vent hose that connects on the driver's side of the tank right next to the muffler. It was leaking right there about an inch away from the end of the nipple. Just as Darrel described in the last post....

Prior I had used the POR15 cleaning and sealing kit to redo my tank. It works very well....But be sure it doesn't clog any of the fuel or vent lines.....

Good Luck....

[mally002]

Wow,

I was away for only a day and sure missed alot. I certainly didnt think my question would bring about all this. The good news, it was the vent hose. Since I filled ALL the way up, it was simply going through the vent hose. There has not been one ouce of gas after I ran some out. I will be replacing the vent hose, and when the tank needs addressing, I will gladly pay for that work to be done. I have ZERO experience with that type of work.

Also thanks to eveyone who responded, I have only been a member here for a short time and you guys have helped me numerous times. It is also comforting to know that everyone puts safety first......That means alot.

From a guy that just loves Z cars and will no doubt have numerous other questions.......Thanks

Randy

[sblake01]

Under normal circumstances, a simple question wouldn't generate some of those responses. But we rarely have normal circumstances here. Having droped many a gas tank in my time, I'd say don't do it unless you need to. If your car hasn't sat for any substantial length of time and doesn't exhibit any of the symptoms of a clogged tank, just replace the vent hose a move on.

[MikeW]

This thread provides a perfect opportunity to use the new reputation feature of this site to provide kudos to those members here who go out of their way to provide excellent advice time after time. In this case some of the information provided is crucial for safely working on our cars and when it comes from people uniquely qualified to provide such advice it once again proves how useful a community this is.

While it's also possible to use the reputation feature to disapprove of posts I've found that the "ignore list" option works well in this sort of situation.

[JimmyZ]

Glad to hear it was "just a hose". Although talking about gas safety has created a lot of "heat" here discussion like this may save someone from making a bad mistake.

Below is a copy of an earlier post I made regarding fuel tank handling safety. A member reminded me of the important need for safety notes/disclaimers. I admit to not being an expert but I have talked to a few people who have done repairs on tanks. Their stories of accidents/injuries/deaths were enlightening.

Here is the copy of an earlier post..

Ah yes... A good point. This is a very important part because of the severe explosion hazard. Should have put up a disclaimer like this...

Gas tanks pose EXTREME explosion hazards which have been known to kill or at least break a few bones while sending someone across a shop. This is something which should not be taken lightly. Before beginning any work on a tank one should remove all traces of gas or anything combustible such as varnish which may produce vapors. Gasoline itself is highly flammable but one should remember it is the vapors which ignite and not the gas itself. Stay at least 100 away from open flames, water heaters, electric motors and anything else which could ignite the vapors. If something should ignite the vapors in a tank, the openings are unable to release the pressure resulting in a serious explosion. I've met a survivor of such an explosion. His description wasn't pretty and he confessed he was very lucky to have survived. Handling raw gasoline is equally as dangerous and requires extreme caution. Place drained gasoline in a sealed, approved container as soon as possible.
End of disclaimer

Here is what my research has found regarding creating conditions for safely work on a gas tank. (Welding, cutting, anything involving sparks or heat etc...)

Since a mistake with a gas tank is a one time thing I'll list methods which have worked for some but should NOT be relied upon. Ususally the work being done on the tank was welding or sweating. The following methods though somewhat sound have FAILED at one time or another and should NOT be used...
Filling tank with water

Assuming tank that has set dry for a year is safe(Can't smell fumes)

Purging tank with exhaust pipe. CO supposedly negates combustion.

Purging tank with inert gas such as argon. (Similar to above)
This method though sound can backfire unless all fuel remains under cover of inert atmosphere.

Washing tank with water

Methods that work and what should be used...

Take tank to radiator shop for boiling and any welding/sweating req.

It is interesting to note that one Renu franchise defumes tanks in an oven. Don't try this at home as I'm sure they have proper controls/safety precautions/equipment.

If you are doing it yourself...

Drain all fuel and place in approved container.

Use strong degreaser to thoroughly clean the tank interior. Clean tank until no residue is showing in waste water. Make sure that once dried there are no fumes present in the tank.

A good follow up for the degreaser treatment is electrolysis as this will liberate a lot of crud that the degreaser might have missed. (Varnish,etc) Electrolysis has dangers of it's own so I will make a page for the electrolysis and place in a later post. It's cool and it really works well. One shouldn't rely on it to remove all rust inside a tank despite using internal electrodes.

Cut access hole in top of tank and sandblast. Stop occasionally and use a light and mirror to see what you've missed. When you have removed 90% of rust then drain sand and apply ospho to inside of tank. Let ospho set up for 24 hours and sandblast to remove all traces of it.

Conduct any sweating or welding on the tank now that it is taken down to bare metal inside and out. Create and weld in patch for access hole.

Apply metal prep such as Hirsh's tank etch to inside of tank. Follow product instructions.

Apply tank sealer per instructions. See my original post for opinions/reasons for using RedKote tank sealer.

Some people use muriatic acid to nix their tank rust but this is very destructive as it eats metal. If the chemical reaction isn't neutralized it could continue to eat things or rust out the tank. The way to be absolutely sure that the rust is gone is outlined above. Make sure that you focus on the seams and any areas which harbor rust when sandblasting. Ospho gets the rest but needs for there to be as little rust as possible for maximum effectiveness.

Schew!!! That was a longgg post. Sorry.

Beandip, you're absolutley right about the need for extreme caution/safety. Thanks

Jim
Attachments are post tank cleaning/electrolysis. Single "L" shaped electrode was used inside tank. Tank was completely immersed in water and washing soda (environmentaly friendly). DC welder on 20 Amps was used for two days. Note how more rust was removed in areas closer to the electrode. Hole was cut in tank AFTER electrolysis. Coatings inside and outside of tank were removed by this process. Tank was sandblasted inside and out afterwards.
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Last edited by JimmyZ : 11-14-2006 at 06:52 PM.

[e_racer1999]

ya, after reading this thread i've pretty much come to the conclusing that i'm going with a fuel cell...

[beandip]

ya, after reading this thread i've pretty much come to the conclusing that i'm going with a fuel cell...

If you are going to take her to the track I would for sure. Otherwise for street use the stock tank is OK . If you could find someone to build a cell that fit under the car and still allowed the spare tire . Then that would be great. I just cringe at having fuel inside the cabin . It's bad enough to have the filler hose pass inside the fender well. A major design flaw in my estimation. If the filler was inside a enclosure of metal to protect it from the inside the passenger compartment . That would be acceptable . But the way these cars are built , if you get hit hard in the right corner you could be french fried . G

[TomoHawk]

If you're going to spend the money on a fuel cell, why not spend it on making a new gas tank that fits to the car? Maybe there's a fabricator in your area.

Like Gary said, you cou'd still have the room for a spare tire, and it would look much nicer for a street car,

[e_racer1999]

true. fabbing up a custom fuel cell/tank that fits in stock location might be in my future...