Aft-axle fuel tank access on 85

[H3LLSP4WN]

i just replaced both front and rear tank i did not remove the bed i removed the straps and disconnected them form the hoses and connector after tilting the tank towards the rear of the vehicle installed the same way no bed removal

 

[Sergey]

Thank you for posting pictures. These are helpful.
Electrical connector on my 85 rear fuel tank sending unit appears to be identical. I finally managed to get it off sending unit.
Fuel line connectors are different! On mine there are two different diameter connectors, one smaller diameter (5/16") and its nylon line is grey color, and another one larger diameter (3/8") and its nylon line is blue.
Plastic clips which hold fuel line connector I had to break with small wire cutter. Despite user manual stating clearly "use only fingers and no tools" to free the connector from the beaded pipe end I could not do that. Hopefully auto parts store will have those plastic clips to replace the cut ones.
Thanks

 

[gandalf]

Those clips are made by Dorman. Any good parts store will have them, or can get them.

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[Sergey]

Hello,
well... to tell the truth rear tank removal and install procedure (without removing truck bed) ended up with what I was feared for. While maneuvering rear tank I damaged blue nylon fuel line, it became kinked, and then its push-on connector also sustained damage (not visible on the picture since it is mostly inside).
I cut off damaged part of blue nylon fuel line with a hope to be able to replace its end and join pipes together.
But things apparently changes over years. My 85 has 3/8" beaded pipe and 3/8" nylon tube. Oddly enough the replacement ends from local auto parts store are for 3/8" pipe with 5/16" nylon tube, or for 5/16" pipe and 3/8" nylon tube.
Will have to order 3/8" to 5/16" union for nylon tubes.

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[riphip]

I did the same a long time ago on my '86 4x4 in sig. Never again. I pull the bed all the time now & take care of other things that need attention while it is off. If you have an engine puller, you can make a simple frame to attach to the arm and lift it off. Otherwise get 3 other friends to help lift off.

 

[Scotty4]

I did the same a long time ago on my '86 4x4 in sig. Never again. I pull the bed all the time now & take care of other things that need attention while it is off. If you have an engine puller, you can make a simple frame to attach to the arm and lift it off. Otherwise get 3 other friends to help lift off.

Frame is recommended! I did two ratchet straps and well, the bed came off but not nicely. Was putting a flat bed on anyways.

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[Sergey]

Ordered 3/8" to 5/16" pipe union from amazon
https://www.amazon.com/gp/product/B008ROV4EM/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
it is described as

• Compatible Pipe Material: Copper, Aluminum and Plastic

Arrived today. Maybe they mean some other plastic, but my nylon fuel line pipes do not fit it. The hole diameter in both nuts is too small. Also there is no inner core for plastic pipe, this union really is for metal pipes, not for nylon pipes.

 

[Sergey]

I did the same a long time ago on my '86 4x4 in sig. Never again.

You are very right on that, never again.

 

[Sergey]

I pull the bed all the time now & take care of other things that need attention while it is off.

When I realized the trouble I got into by damaging nylon fuel line I did in fact re-visit the option of removing truck bed.

Went under the truck and located six(?) carriage type bolt ends holding truck bed to frame cross members. All six ends have significantly rusted nuts. Tried to loosen two(2) of them (best candidates). What happened then is that entire bolt rotated together with a nut as one piece, and rounded the square opening in truck bed (which held square neck or carriage bolt). I guess I am not the only one here in this situation, these bolts have to be cut off then... and even then two new carriage type bolts won't hold - square holes are gone already.
So I abandoned the idea of truck bed removal altogether and keep dealing with the problem I created.

 

[TahoeTom]

To prevent rotation of carriage bolts, tack weld them to the bed before going after the nuts with an impact. I still have one stubborn one I need to cut.

 

[riphip]

Use plenty of 'loose juice' before attempting to remove rusted bolts. Carriage bolts. next size larger, should work. Get some silicone grease from amazon and 'lather' the threads.

Rubber fuel hose will slip over the nylon lines tightly + use hose clamps

 

[Scotty4]

Here is my transfer setup. I put hose over the front tank return (right side of pic), then check valve, tee from rear supply, then the factory connector. The line fit snug and with a small hoseclamp, I have not had any leaks and everything works as it should.

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[Sergey]

Rubber fuel hose will slip over the nylon lines tightly + use hose clamps

For the same diameter of nylon pipes - yes. But I need to join different diameter nylon pipes - remainder of original 3/8" blue line to new 5/16" from new push-on connector. Something like this would work perfect, if it were made for nylon pipes.

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[Sergey]

Finally I fabricated 3/8" to 5/16" union for nylon fuel lines. Installed it on my truck and drove to gas station to test.
Put 7 gal of fuel into rear tank, switched engine to rear tank and idled at gas station for 6 minutes. Checked under the truck and found no leaks. That's encouraging.
However, fuel gauge shows 3/4 tank, which is as wrong as it was before, since rear tank is original with capacity 19 gal.
Drove truck home and met with horror faces pointing to trail of fuel on pavement left by my truck. Pulled over and yes, rear tank now leaks fuel significantly.
Worse yet, fuel leak on right side drips right onto exhaust pipe. Ouhhhh.
Truck is not drivable until rear tank is pimped out.

I am devastated. Wish I would not even proceed with rear tank "repairs". Rear tank never leaked before my hands touched it.

Learn to do things yourself. This accomplishes two things. First, it helps you keep some of your money in your pocket. Second, it will give you some understanding of why things cost what they do.

The observation above is true for many people, but not for some, me included. I should not do that thing myself.

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[nelstomlinson]

Those Ford fittings and nylon lines are a disaster. Just replace the entire mess with metal lines where you can, rubber fuel hose where you must.