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Introduction

The purpose of this guide is explain the procedure to remove the fuel tank from a Jimny.

Note: Someone should add some neat pictures.

Precautions

Petrol (gasoline) is not that much flammable as a liquid as most ordinary people believe. However, it is a super highly evaporable liquid. It is the petrol vapor that is one of the most flammable and volatile gases known to humans (and to most aliens).

Petrol begins to evaporate as soon as temperature rises from absolute zero to MINUS 40 degrees Celsius! Now imagine how much it evaporates at +30 C for example.

Therefore, it is highly dangerous to perform certain types of work (particularly involving heat, sparks or electrostatic discharges) even on a completely empty petrol fuel tank, even if it had been flushed with water several times in the meantime. Not to mention a non-empty petrol fuel tank!

You should have protective equipment on you (gloves and glasses as the minimum) and a big ugly fire extinguisher ready nearby. An assortment of talismans and amulets nearby can only help as well. You should also avoid drilling and grinding anywhere near an open petrol fuel tank, and especially not directly on it. If you need to drill or grind a petrol tank itself, special precautionary procedures are required which are not explained here. Smoking is also particularly bad for your health.

Diesel fuel is not nearly as flammable as petrol, so it is relatively safe to work around or even on (empty) diesel fuel tanks. It is usually much harder to ignite diesel fuel than most people believe it is. Even when it does ignite, it does not burn nearly as "pompously" as petrol does.

Keep the vehicle battery disconnected whenever you are working something with the fuel tank.

Preparations

1. Unless you are a Mr. Olympia wannabe bodybuilder and/or a masochist, it is the easiest and most convenient to remove (and particularly to reinstall) a fuel tank when it is nearly (but not completely) empty.
   • However, it is not possible to "siphon" the fuel out of the tank through the fuel filler hose, as there is a fuel anti-theft protection mechanism at the hose connection into the tank.
   • Therefore, the only easy way to empty the tank in place is to have the engine running until it consumes almost all the fuel.
     • A complicated alternative is to lower the tank from the vehicle slightly, and then remove the top plate where the pump and filter arrangement is and extract fuel through that opening in the tank.
       • However, since the tank has to be significantly lowered to gain access to its top side, this puts the meaningfulness of this method into question.
2. Disconnect the vehicle battery and short both leads to the body to earth everything.
3. Have a foam or CO2 fire extinguisher nearby.
4. Become a non-smoker, at least temporarily.
5. At least a few hours before embarking on this job, spray all the bolts to be removed with WD-40 or similar thread penetrating lubricant for easier removal and reduced risk of shearing a bolt.
   • Those bolts are:
     1. On fuel tank's fuel filling hose connection to vehicle's body;
     2. All the bolts holding the fuel tank and its guard to the vehicle chassis;
     3. The bolt connecting the ground wire to the rear of the fuel tank.
     4. On the rear propeller shaft;
        • Not required if doing only a mini-removal (read more below);

Mini-removal for underbody anti-rust coating

If your goal is just to rust-proof the vehicle floor above the fuel tank, then it is not required to remove the fuel tank completely. It is much simpler just to lower the fuel tank onto the exhaust pipes and onto the rear axle. This creates about 8 cm of additional space (in addition to the existing gap) between the fuel tank and the vehicle floor above. That is just enough to reach above the fuel tank with a pressure washer and later with an underbody coating spray gun. This amount of fuel tank displacement does not strain the pipes/hoses and the wires (except one wire, see below) going to the fuel tank, so there is no need to disconnect those.

One major advantage of this level of disassembly is that it imposes (almost) no risks of dealing with petrol vapors, making the mini-removal a much safer as well as easier endeavor compared to the full removal.

There is no need to unbolt or remove any other part the vehicle underbody to achieve this level of success.

The only two additional things to disconnect from the vehicle (apart from the fuel tank itself) are:

• The fuel filling hose;
• The single black wire which connects the rear left part of the fuel tank to the vehicle body.
  • Read more about this important wire in a dedicated chapter below.

Full removal procedure

1. Remove the rear propeller shaft (between the transfer case and the rear differential).
   • Mark the exact mounting position of the shaft in correlation to the rear differential and to the transfer case, as you will need to put it back exactly as it was mounted.
     • This because propeller shafts are balanced for certain mounting positions in the factory.
   • Read the wiki article "Universal joint replacement" for more info on removing and installing propeller shafts.
2. Remove the small inner plastic wheel arch liner from the rear left wheel arch, which sits towards the fuel filler flap.
   • It is held by a few plastic clips, which can slowly be prised off with a flat screwdriver.
3. Release the clips on the two pipes which connect the fuel tank with the fuel filler cap and free the pipes from the vehicle body.
4. At this point you can either disconnect both hoses from the fuel tank, or unbolt the bolts which attach the hoses to the vehicle body inside the fuel filler flap housing.
   • It has been reported that (predominantly in older Jimnys) those bolts can become stuck and it is easy to snap the fuel filler hose head, creating a lot of unplanned hassle.
     • Therefore, it might be a safer option to remove the hoses from the tank and let the hoses hang from the vehicle body.
5. If you disconnect the hoses from the fuel tank, then stuff the openings in the fuel tank with some rags.
6. Disconnect the single wire from the rear left edge of the fuel tank.
   • Read more about this important wire in a dedicated chapter below.
7. Undo all the bolts which hold the tank to the chassis, while simultaneously supporting the tank with something.
   • The tank is not heavy when empty, but if full is at least 45 kg.
   • A possible holder for the tank might be three or (better) four vehicle jacks topped of with a strong and wide wooden board.
     • Take extra steps to prevent the board or any of the bottle jacks from toppling over!
8. Slowly lower the tank enough to reach the small bolts on the top.
   • Blow over the tank with an airline to clear loose crap and debris.
9. Remove the small bolts.
10. The fuel pump/filter arrangement will remove all as one and is about 30cm long (the depth of the tank).
    • Pipes do not need to be disconnected as there is enough flex, but the wiring connector may need to be unplugged.
11. It is highly advisable to protect the filter setup with some clean plastic clingfilm or bags, and also to protect the hole at the top of the tank from dirt ingress.
12. Tank is now free to be taken out.

Special attention about the grounding wire

• A single wire connects the rear left part of the fuel tank to the vehicle body.
  • That is the electrostatic potential grounding wire.
• As soon as you disconnect the wire from the fuel tank, wrap the connector on the wire with an insulating tape, as well as the connection point on the fuel tank itself.
  • This way, they will not get greasy, dirty or overcoated if you plan to do some underbody coating etc.
• Later on after you reassemble everything back together, use an ohmmeter between the fuel tank and a bare metal point on the vehicle body to check if the reconnected wire truly provides an electrical connection between the fuel tank and the vehicle body.
  • If there is no connection indicated, you need to additionally clean the mating area between the wire and the fuel tank.

Recommended additional works

Underbody rust protection

While the fuel tank is removed from the vehicle, it is highly recommended to clean the exposed underbody of the vehicle which the fuel tank used to obstruct the access to, and then to properly rust proof it. Jimnys 3 are notorious for developing severe corrosion issues in the rear floor section and especially in the boot floor. This is a unique opportunity to remedy or to prevent that.

Read the wiki article "Rust protection" for more info.

Petrol fuel filter replacement

For petrol Jimnys 3 (and possibly Jimnys 4), also don't forget to check the condition of the petrol fuel filter (which is part of the fuel pump assembly which you had taken out from the tank). The factory specified replacement interval for that filter in Jimnys 3 is somewhere in the range of 200 000 km. The only opportunity to replace it is when the fuel tank is removed from the vehicle, so you might as well use this opportunity to do so even if the specified interval has not yet been achieved.

Read the wiki article "Regular maintenance intervals and consumables" for more info on part numbers and replacement intervals.

Installation of a heavy duty fuel tank protector

This is an ideal opportunity to install a heavy duty fuel tank protector (for harsh off road use) instead of the standard factory fuel tank protector.

LPG fuel tank installation

You might consider installing a special mini petrol fuel tank + an cylindrical LPG tank in the place of the original fuel tank.

This is explained in full detail in the wiki article "LPG fuel supply system".

Installation procedure

Refitting of the fuel tank is essentially the reverse procedure of the removal, except making even more sure everything is super clean.

It might be a good idea to grease all the bolts with copper grease before reinstalling them back in place, as this will reduce the risk of them seizing in the future.

If the bolts which connect the fuel filler hose to the vehicle body have sheared off during removal, life might still be worth living:

1. Just put your left hand up into the wheel arch to push it into place.
2. Then stick a rag into the filler hole.
3. Drill new holes next to the old holes through the body and the plate around the filler hose.
   • Don't drill too fast. The metal in that place is quite thin anyway, and if drilling slowly, no heat and no sparks should be generated.
4. Finally, just use automotive self tapping screws to hold the filler neck connected in place to vehicle's body next to the old bolts.

Problems after installation

The only problem which you might encounter after the completion of the installation is that the engine will not start. This usually means that the air is trapped somewhere in the fuel lines and needs to be purged out.

Someone needs to write some guidelines how to purge trapped air from fuel lines.

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Page last edited on 22/12/2021 by user Bosanek