I've read section of FSM about removal BUT i decieded to ask from the pros too. My current tank is ok, but PO had painted it over with the same colour as the car, and it looks ugly.

Is this a tricky task? Any hints?

It's not complicated. It's just time consuming. I think I recall the order correctly. Make sure you drain the tank well. Remove the wires for the sender. (You may want to get a new O-ring & locking tab for the sender in case you need them.) Support the tank. (I prefer to use a floor jack.) Take off the straps and lower the tank. Detatch all of the vent hoses, the filler hose & fuel lines. Remove the tank.

After them straps are undone and hoses off it pretty much falls out, but needs to pivot forward a bit due to the rear skirt. If alone put a smaller sheet of plywood or something on the jack as to not dent the tank and to give it more leverage. If you have someone around I find it best to just lay down under it and rest it on your chest as it comes down and other person there can undo any hoses or hand you tools as needed. But thats just me, I do transmissions like that too cause I get tired of fumbling with another jack. Careful on the ring to undo the sender unit if you plan on taking it out inspecting it or the inside of the tank, the tabs will break off fairly easily if you start whacking at it. People say not to use a metal screwdriver due to potential sparks, not really sure if tank explosion is even a possibility, but I suppose that word of advice came from somewhere! I just use a piece of wood or scrap brass, something like that. Also, if you are removing the unit, keep it clean as you do it, any dirt particles around that ring as you turn it will surely fall into the tank as you remove it, a small hand broom or something like that is always nice to keep brushing out the dirt so it does not enter the tank.

Thanks for the info. Is that o-ring some standard size or do i need to order it from somewhere?

I've seen it on MSA & eBay. Maybe even Nissan still carries it.

Here is for a 280z. Not exactly the same but general idea http://atlanticz.ca/zclub/techtips/fuel/gastank/index.htm

Some nice photos of the early240z emission lines to the tanks and drawings here: http://www.classiczcars.com/forums/showthread.php?25857-Rating-the-factory-240Z-fuel-vent-hoses

Edited January 25, 201213 yr by Blue

Here is my experience with the removal... maybe a tidbit of info there.

http://www.classiczcars.com/forums/showthread.php?43422-Strong-fuel-smell-in-the-car-when-I-turn-LEFT&highlight=evaporator+tank+removal

I did not document as much of it as I wanted to, but some great advice in the thread none the less.

Dammit, I typed out a nice, long response and my computer decided to reboot.

Dropping the tank isn't terribly difficult, but be warned that the "While I'm At It" syndrome will take over. The tank drop will be easy if the strap threads and nuts are not rusty. It they are, soak them for several days before you begin. The biggest thing you will find is old, dry vent hoses which, while you're in there, should be replaced. This requires the interior trim panels to be removed and some fabrication work since the large vent hose in the back of the tank is NLA. It has a 180° bend molded in, so bulk hose cannot be used without additional hardware. You can find a how-to online to make a copper fitting to replace the 180 in the hose. This is easy, but I would recommend incorporating beads on the ends of the copper to keep the hoses in place. I didn't do this and had the hose pop off. I had to drain and drop the tank at the race track which cost me a lot of time and aggravation. When you replace the hoses, be sure to use fuel-rated vent hose and not heater hose. I had to special order the 5/8" fuel hose as it's not very common.

Chances are very good that all of your hoses are way overdue for replacement anyways, so use the opportunity to do it right. Be sure to seal the hoses where they go through the floor. You are probably getting exhaust fumes sucked in through the old grommets.

The fuel sender seal is available at any Nissan dealer, the part is still used in modern cars. It costs about $4.50. A parts guy will be able to cross-reference it for you.

I'll +1 everything said so far. It's not difficult, just time consuming. I ended up replacing the fuel filler neck, both sections of flexible tube going to and from the tank to the main fuel supply and return lines, all the grommets and all the vapor system hoses. A couple of the hoses were parts-store approximations, so I also used a couple of those parts-store bendable metal hose supports to keep them from kinking. As a final couple of steps, I sanded/painted the tank straps and put gaskets material on them as a new backing, and I repainted the fuel tank. In my case, painting the tank was necessary as it was a leaking fuel level sender seal that started the entire process, and the leaking 4.5 gallons of gasoline ate much of the tank paint as it escaped.

I didn't use a service manual, it's a very simple system if you're savvy with tools and can observe how the pieces all fit together as you disassemble them. I recruited a friend to help with the new filler neck, that rubber tube and its related ring clamp at the base of the tank are worlds easier with a second pair of hands.

P.S. - for rusty tank strap nuts and/or rusty ring clamp screws, PB Blaster is your bestest friend.

Edited January 25, 201213 yr by BTF/PTM

Messing with sender unit seemed to cause some problems? How common is that? ( i hate doing electronic stuff!!) And does Nissan sell those sender units or are they NLA? Braided hoses i have, seem to be in ok condition, at least in the cabin side. I had some smell issues but they are caused by bad hatch w/s and leaking watercock.

But i have to wait a little while before i start...its -20C out there and my garage has only small heater

The senders are available via eBay & MSA. However, they are essentially a potentiometer. Unless you took out the sender, there is little chance of breaking it, though they can wear from the float going up and down. What exactly did you mess with? Search around here. I know I've posted on how the fuel gauge circuit works. It's pretty simple.

I am in the process of restoring my fuel tank. I tried cleaning it but there was some debis in it after all the years the car has been on the road. So I removed it two weeks ago, boiled it, resealed, primed, undercoated, ordered a new sending unit and am waiting on the hoses to arrive so I can reinstall. Its also a good time to replace aging gromets and other aging rubber. I figure I only want to do this once. The overall process should take about a month due to waiting on parts to arrive.

fuel sender info: http://www.classiczcars.com/forums/showthread.php?43765-Hard-Wiring-The-Fuel-Sender-Connector&highlight=fuel+sender