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S IV Fuel tank removal

Discussion in '"Stock" Alpine' started by SIVAllan, Jun 27, 2007.

  1. P. Scofield

    P. Scofield Bronze Level Sponsor


  2. SIVAllan

    SIVAllan Donation Time

    Hello all,

    Am finally at work reassembling the fuel system.

    One question?

    The fuel level sending unit fits over a gasket and beneath a lock ring.

    When I assemble this, the sending unit does not fit tight. I can not rotate it like the hands of a clock, but I can easily move it side to side, etc.

    I tried using 2 rubber gaskets but that is too thick.

    I'm wondering if the lock ring was "altered" a bit by the radiator shop guys.

    Looking at the top side of the lock ring, there are three slots I assume are used to help turn the lock ring into place within the fuel tank's neck.

    Each slot has a "prong."

    Are the prongs supposed to be bent downward, and thus hold the sending unit secure against the rubber gasket?

    If so I can bend them, but don't want to monkey this up.

    Your comments would be very much appreciated.

  3. Bill Blue

    Bill Blue Platinum Level Sponsor

    Allan, If I remember correctly, I ran into the same situation with my sender. I just centered it the best I could and tightened it. I would like to say it worked fine, but I've yet to put gas in the tank. Maybe next week.

  4. SIVAllan

    SIVAllan Donation Time


    I believe the sender will work Ok, even with a little wiggle at the lock ring.

    It occurred to me though that without a tight seal, fumes could/would leak out of the fuel tank and into the boot.

    I guess I'll try and tap the small "prongs" downward, and re-assemble.

    Failing that, although I would not want to do it, a sealer could be swabbed over the sending unit once it's back in place.

  5. Bill Blue

    Bill Blue Platinum Level Sponsor

    Allan, are you saying the unit will move side to side after the ring is tightened? If so, then yes, more clamping effort is needed. If you are able to rotate the clamping ring beyond "maximum" , something is amiss.

  6. SIVAllan

    SIVAllan Donation Time

    Thanks Bill.

    I tried a few things to no avail, then noticed that one of the indents in the fuel tank neck was not as indented as the other two.

    Fixed that, adjusted the other two, and now the sending unit is secure.

  7. SIVAllan

    SIVAllan Donation Time


    Am taking the S IV fuel tank effort another step forward, but need some advice <s>!

    I replaced the fuel line with a flexible one.

    The plan has been to use the original metal fuel line fitting, and some of the pipe, about a foot beyond the bubble flare, and clamp the flex hose to it.

    Unfortunately I believe some of the goo that started this epic remains in the section of metal pipe I planned to use.

    I suspect the best answer is to replace that lenght of fuel pipe, using a new bubble flare and the old fitting to the crossover tube.

    Before I get a brake shop to do this -- is there anything special about the original bubble flare?

    I'm sure any brake shop can do a flare but am NOT sure it would be either the same, or even close enough.

    Any suggestions would be greatly appreciated.


  8. Bill Blue

    Bill Blue Platinum Level Sponsor

    I'm not so sure any brake shop can do a bubble flare. They are pretty uncommon.

    I'd try to cut the tube pretty short, say 3-4 inches and try to clear it with a piece of wire or something of that nature. But I'm cheap and try to use as much of the existing hardware as possible.

    How's things going with the crossover hose?

  9. SIVAllan

    SIVAllan Donation Time

    I can cut to that lenght, no problem. I felt that a better place to join the flex hose would be back near the spare tire well, after the "fold" that holds the fuel line in place beneath the boot. But I'll use a short section rather than hold this up.

    I hope to file a "final" report soon, if the monsoons don't return as predicted.

    But basically almost everything is in place, fuel tanks, crossover tubes, body/tank braces, fuel line to fuel pump, fender well bolts. I need to inspect all the parts and check each clamp for tightness.

    The crossover tube was interesting to do if only because the SS connecting hoses are so well made. They fit very tightly, hardly any clearance. I put the tubes together to the maximum extent possible BEFORE installation.

    The balance pipe remains an issue, but I'm on the trail. A buddy at Emory U. (across the street) finally dropped off a huge cataloge they use to order scientific hoses and equipment. I think I will find what is needed there.

    Next step is to connect each end of the fuel line and the overall task is pretty much done (except for the balance pipe).

    I will pour in exactly ONE gallon of fuel to test the fuel sending unit and fuel gauge, and the fuel pump (after disconnecting the fuel line at the carbs and diverting it to a container). I don't know what is the minimum amount of fuel needed to test the sending unit and gauge, but will add a second gallon if needbe.

    Getting real close now...

  10. SIVAllan

    SIVAllan Donation Time

    Yikes, a setback.

    The crossover tube's downspout to the fuel line either has monkeyed up threads, or is of a slightly arger size than the S IV's central crossover tube's downspout.

    The fuel line fitting won't fit to the downspout.

    So...gotta yank it out and see about the threads, and/or a fitting to the fuel line that will screw on to the downspout.

    Back later...

  11. SIVAllan

    SIVAllan Donation Time

    Before pulling the crossover tube I located for examination the downspout nut I torched off the S V parts car crossover tube.

    It fit. I believe it is one mm larger than the S IV nut, which explains why the S IV nut would not fit the S V crossover tube downspout.

    The S V nut is also different on the inside; it has thinner walls, and the exit hole is larger than the S IV nut's exit hole.

    The larger exit hole made for some wiggle with the bubble flared section of metal fuel line being used to connect to a flex fuel hose running to the fuel pump.

    I felt a washer was needed to enable a proper, "wiggle free" fit of the section of metal fuel line.

    After a trip to the hardware store, I tried a number of metal washers, none really worked.

    A standard rubber faucet washer worked well. Such a washer was pressed into the S V nut, then a bit of the same size as the metal line was used to drill out a proper sized hole. Voila!

    Once installed, a simple test of the fuel system was made by adding exactly One gallon of fuel, and spinning the engine.


    After purchasing the car in late April, FINALLY fuel pumps to the carbs.

    Oddly, the fuel gauge registered 4+ gallons of fuel, although only one gallon is in the tanks.:eek:

    I attached fotos of the nut solution, and the odd guage reading.

    Will file a final (I hope) post on fuel system reassmbly early in the week.

    For now, it's time for a cold beer.


  12. Bill Blue

    Bill Blue Platinum Level Sponsor

    Allan, don't know when the change was made, but my Series V crossover tube uses a compression fitting. This is like the fitting commonly used on sink hookups. On my car car it was all plastic, other than the brass nut.

    Anyway, all this means it uses a different thread size than the bubble flare.

  13. SIVAllan

    SIVAllan Donation Time

    Thanks Bill,

    That's good to know.

    I think the drilled out, pressed in washer will work fine on much the same principle. As the nut was tightened, the bubble flare was snugged into the proper place.

  14. Ken Ellis

    Ken Ellis Donation Time

    Re: your gauge reading... One of the (many) reasons for incorrect/high gas gauge reading is a failed instrument voltage regulator. You can replace with OEM, or you can check out Ed's offering (see the thread on this forum). Basically, the fuel gauge and temp gauge are voltmeters displaying from zero to about ten volts. If the voltage to the gauge is too high, the reading can be either 'too hot' or 'more gas than you really have'. Now, whether it will result in 4x the gas you have, I'm not sure. You may have a sender that is either the wrong one, or is defective in some way, or the gauge may be faulty. But, since you know you have 1 gallon, the next step would be to measure the output of the instrument voltage regulator, and log that. Then measure the voltage back at the sender, then back at the input to the meter. Voltages whose only characteristic is that they're measured at the other end of the same wire should be pretty darn close -- I'd say within 1 volt. If the output of the instrument regulator is 12 instead of 10, then check the ground on the regulator. If the ground is good, then the regulator is probably bad.
    Note that this is up under the center of the dash, below where the clock goes.

    Check out other thread for Ed's info. When I last read, he had one left.

  15. P. Scofield

    P. Scofield Bronze Level Sponsor

    Correct! And we usually find out the hard way! This happened to me when trying to use a Series III crossover in a Series V car years ago. Strange they would change these but they did. And one of them (I don't remember which one) is a very odd size and hard to find.


  16. SIVAllan

    SIVAllan Donation Time

    Thanks for the note. I'll print it and take it to the S IV, and see what I can determine. A unit from Ed arrived today...

    Am still in "pre-flight" maintenance mode, gotta yank the oil cooler, etc., so it may be a week before I can investigate.

  17. SIVAllan

    SIVAllan Donation Time


    It would be great if someone with a parts manual could post which Series uses which nut. That would save people a LOT of hassel over time...

  18. SIVAllan

    SIVAllan Donation Time


    A note on fuel tank issues: step 4 reassembly

    • Fuel tanks and crossover tubes having been relined, and hoses and clamps obtained, it’s time to reassemble.
    • Installation is the opposite of removal <s>.

    After reinstalling the fuel level sending unit, the fuel tanks were installed first.

    Boot lid springs and hinges were installed, then body/tank brackets were added.

    Clamps were put on all tubes prior to assembly.

    Tube hoses were put on the outer tubes, which were then connected to the fuel tanks.

    Tube hoses were then put on either end of the central crossover tube, which was slid into connection with one fuel tank’s tube.

    The final hose was then knocked into place using big pliers to hold it, and a heavy hammer. Nothing was tightened securely to allow for final adjustments.

    All the hoses then had to be adjusted, again using big pliers and a hammer. The hoses fit very tight, and don’t slide without effort.

    Once the whole system was in place and adjusted, everything was tightened down, and crossover tube to body bolts added along with fender well bolts.

    The grommet for the crossover tube outlet needs to be installed from the outside of the body, pressing in. I put it on the inside, thinking I could press out but that’s a bad plan, had to order a replacement.

    If a new fuel line is installed, it is probably best routed using the body clamps for the old line (which is what I did).

    Fuel cap reinstalled.

    Fuel was added to test for leaks.

    If a different Series crossover tube is being used, verify beforehand that the correct fuel outlet nut is available. As noted by others, the size of the outlet changed for different series. A Series IV nut will not work on a S V tube.

    Normally I believe installation of the balance pipe would be the first step. It does not have to be first, but that’s the most convenient time.

    I don’t have one yet due to problems of space inside the body channel, as discussed. I’m using a temporary one for testing purposes, and will file a separate post regarding the solution to that issue.

    If rust is a concern, there will never be a better time for treatment.

    Fender wells were sanded while the tanks were out, coated with a rust-to-metal agent, and then coated with a zinc laced cold galvanizing spray before coating with a rustoleum primer and paint.

    Fender well drain holes were verified to be in good working order.

    The trunk floor needed attention and received a similar treatment.

    New trunk floor grommets were ordered.

    I want to thank everyone for posting, emailing and/or conversing by phone regarding this effort.

    It could not have been completed without your experienced advice.

    The standard Haynes, Clymer, Chilton, etc do not cover this procedure. Not sure but I don’t think the WSM does either.

    A couple of pics are posted simply to present a before and after of the fuel tank/boot area. It’s not Moonstone <s> colored, but is a good bright white that should remain rust free until such time as the S IV goes in for painting and undercarriage treatment.

    Best Rgds,



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