Gas Tank Sending Unit

Engine, Transmission & Driveline

  1. GJS

    GJS Senior Member

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    I ran into an issue I described in another thread but wanted to ask:

    I ran the Monaco on the 4th, put some gas in it and parked it for the night. The next day there was a pool of gas under her. I dried all that up as best I could then went looking for the leak. Turns out that the lock ring around the sending unit had loosened up, not sure why other than that I hadn't seated it properly when I did the tank ..

    Anyway, I can't seem to get the car up in the air enough to get a good grip or angle on the ring to snap it back. I've tried going in at the front side of the rear drivers wheel well with a pine dowel to tap it back into place ... the pine just seems too soft to move it. Also, it's uneven pressure being applied to the tab on the ring and I don't want to bend everything to hell. I don't want to go after it with metal and risk a spark.

    Anyone got any tricks or "idears"? I'm considering limping it down to ANY shop that'd have a lift at this point but that too is rather dangerous.
     
  2. HWYCRZR

    HWYCRZR Well-Known Member FCBO Gold Member

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    A brass punch. Harder than wood, won't spark. A couple taps all around to make sure it is evenly against the seating ramps. Then one good hit on one of the tabs should send it over the ramp to it's seat. Then a tap on the opposite side to make sure it is seated around. You will probably have to shimmy under to get a good angle or find some small competent kid that you trust with a hammer and brass punch around your gas tank. If you can jack up the body and block it up leaving the rear wheels on the ground you should be able to fit. Plus it will give you more room between the axle and sending unit. Support it well so it doesn't fall on you.
     
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  3. Ripinator

    Ripinator Senior Member

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    If you can jack the back end up high enough to get a couple of fully extended jack stands under the axle housing, there should be enough room to get under it with room to swing a hammer. I would use a piece of oak dowel or some other similar hard wood to tap on the "ears" and tighten the ring. Also, please note the re-pop rings are thin and often don't seal correctly.
     
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  4. GJS

    GJS Senior Member

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    Ah. Ok, so: right idea, wrong material. I was kind of thinking inside the box due to what I had at the house. I'll just scoop up an oak dowel and a brass punch tonight and giver her another go. Gotta get her out in the wind, man. She's already spent too much time in the garage this year!

    Good call on the re-pop rings. I was wondering why this would have happened in the first place and didn't even think of that.
     
  5. moper

    moper Well-Known Member

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    They can be rough to get to seal if the ring is not centered. The tank can be dropped with fuel in it - its just more care needed. Lower the tank, tap the ring into place, and raise it back. A lift and transmission jack make it easy. A floor jack and jackstands will work but prob be messy.
     
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  6. GJS

    GJS Senior Member

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    Yea, the tank is about as full as it gets and I don't have a trans jack. I'd prefer not to drop it if I can avoid it.
     
  7. Rapidtrans777

    Rapidtrans777 Active Member FCBO Gold Member

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    Exacty. It is a very tight fit and the ring has to be centered or it will leak. I thought I had one locked in. Put the tank in, filled her up and it leaked. Dropped the tank and realized I had another almost 1/8 of a turn to go. Unless you have the specific spanner wrench to fit and are using a hammer and brass drift you need to alternate your hits on the tabs to keep the ring centered.

    Please! An acquaintance from town died last summer, his car fell on him while working on it.
     
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  8. GJS

    GJS Senior Member

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    I have a hard time getting under cars that are sitting on their wheels.... for that very reason.
     
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  9. Yatzee

    Yatzee Active Member

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    I'm a proponent of "do it right the first time" so here's my solution. Siphon the tan to about 1/4 full. Using a hydraulic jack with a square piece of plywood on the foot of the jack undo the straps and lower the tank. Remove all lines. You may not be able to lower the tank at all depending on where the fill tube is and how it's connected so you may have to do a bit more work or elect to have a shop do it. Once down, inspect the position of the ring being sure it has not slipped sideways. You may have to remove and insert it all over again. Once started you can lightly tap the ring from alternate sides with an aluminum or brass bar to keep it on center and get it tightly under the hold down tabs. There is nothing worse than a poorly seated sending unit that spews gasoline every time it sloshes in the tank or when you accidentally over fill the tank and this situation is certainly not going to fix itself over time.
     
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  10. Wollfen

    Wollfen Old Man with a Hat

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    I have had success jacking up the front of the car then sliding under to work on the snap ring on the gas tank sender unit. This helped me with not having gas come out while adjusting the float arm to get the fuel tank reading right.
     
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  11. Mudeblue

    Mudeblue Member

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    Do it right and do it safe! Drain the tank, drop the tank and fix it. Not a big deal; couple of hours at best! Again, do it right and do it safe!
     
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  12. stubs300

    stubs300 Senior Member

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  13. GJS

    GJS Senior Member

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    Alright. She comes out Saturday.

    Thanks, guys.
     
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  14. live4theking

    live4theking Old Man with a Hat

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  15. Turboomni

    Turboomni Senior Member FCBO Gold Member

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    Just bought one,thanks for the link stubs
     
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  16. 3C's & a D?

    3C's & a D? Well-Known Member

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    I'm all for safety, no use having a car if your dead, but, dropping the tank to tighten the gasket? That seems excessive, and given my personal experience, not warranted. Brass punch is what you want, drill a shallow reverse counterpunch if possible to grab better. And, is this a new tank? With new lockring? If so, you can tighten it all you want, it will still leak. The new lockrings are thinner and lack the wave design.
     
    Last edited: Jul 13, 2018
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  17. GJS

    GJS Senior Member

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    Original tank, new unit, new lockring. I'm going to try tapping a few more times simply because if I can get it tight (or tighter), I'd much rather run the gas out of the tank than drain an entire tank of gas ..

    That said, there's a few other things weighing in on dropping the tank, mainly inspection of the trunk pan's underside. We'll see. Either way she's coming out again within the next few months.
     
  18. stubs300

    stubs300 Senior Member

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    Just as good if not better! What you people also fail to realize is that the gaskets are also thinner than the originals. I had to use 2 gaskets that were gunked together so they wouldn't leak. Sometimes, you have to think outside the box! I know that's complicated for some people.
     
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  19. 3C's & a D?

    3C's & a D? Well-Known Member

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    Well there you go, that is the right tool for the job and I can understand that it would do the best job, however if you're using it on a new lockring and gasket, it will still leak. GJS, did you happen to save the original lockring? I swear someone could make a small amount of money correctly repopping those.
     
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  20. Turboomni

    Turboomni Senior Member FCBO Gold Member

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    Seems to me saving the old lock ring is key here.