BUILD THREAD “The Juggernaut”

Your original sending unit "vent" is a vent, as you stated. On G-bodies with gas, there's only TWO types of sending units. A two-port and three-port. The two-port has a charcoal canister vent and a fuel supply to the pump. In the three-port, they added a return-line from the pump. Depending on which type of fuel pump was used, that determined which sending unit you got. And that seemed to change year over year. I really don't know what the criteria was. Oldsmobile V8s used the three-port a lot. Chevies, not so much. The part numbers are only 1 different than each other as well. 25001612, the two-port, is what you have and 25001613 is the three-port. The last number just happens to coincide with the number of ports for A/G47. Wagons are similar, but obviously different part numbers (25000757 for 2 port and 25000758 for 3 port).

There is an actual RPO for the fuel line return. It's K15. Although, I do not know what triggers it. ALL 307 VIN 9's use it because ALL 307 VIN 9 engines came with the same type of fuel pump which has a return line.

Looking at john87442 crusty 442 frame below, you can see the vent, return, and supply. All G-bodies should have at least the vent and supply. The "heat shield" plate below the supply/return lines in the pic is only found on VIN 9 cars with the dual exhaust. Single exhaust cars didn't get those.

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This portion below shows where the lines route to on the forward part of the frame. Where the canister is on the passenger side. When the canister is on the driver side, you should see the vent line run right up the driver frame rail in front.

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Thanks for the refresher sir, very much appreciated. I knew the vent line went to the charcoal canister, but was unsure about the third line as my 305 equipped cars never had the return line from the fuel pump.

I’ve repurposed the stock 2 line pickup the car originally came with now last night into a dedicated fuel level sending unit with just a vent.

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It’s Mike’s day to help out here today, so one of the first things we’re going to tackle is this bullshit:

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Frigging aftermarket Spectra tank, I can’t even attach the new gas cap until we readjust the filler neck angle.

Picked up the newer style factory replacement cap you linked to.

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After that, we’re going to drop the tank, check out what needs to be done to tweak the float arm to clear the Aeromotive pump and hanger, then get it installed in the tank. The Summit order arrived Friday, so we’ll also be looking at making the wiring connections with the new pump wiring harness.

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Doing a proper update today, time to get everybody caught up. My Summit order showed up Friday…

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…so yesterday I set about installing the clamps and getting the hoses cut to length and the new hose ends on.

I started by drilling and tapping the frame above and beside the spring pocket for the clamp that will secure the hoses to the frame. It was a little tight and tricky, but I got it done:

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Once I had that in place, then I routed the hoses through it, and installed the other clamps where they seemed to need it. Here’s another look at the progression from the Aeromotive pickup to the dummy hardline pieces, now with the proper clamps installed.

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Once I was happy with the routing and was at the hardlines, I marked and cut the hoses, installed the new ends, and connected them to the hardlines:

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I’m very happy with the end result, the hoses are up high and clear of any potential damage or issues. In fact, they route very close to the factory configuration.

Today, Mike and I finished up early. Doing those mods to the tank didn’t take nearly as long as I thought they would.

Adjusting the filler neck proved to be a non-issue, we were able to move it up into the correct position by hand. Simply pushed up on the underside of the neck with the tank still installed, and it moved just enough.

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New cap looks right at home on there too.

From there, we dropped the tank, and got a good look at what had to happen to make the float and arm clear the Aeromotive pickup. Rather than risk throwing the float height and travel off by bending the arm, we decided the best course of action was to actually cut the pickup tube at the straightest point, and reclock it to where it needed to be. We used a mini tubing cutter to make the actual cut, no loss of material that way that would affect the installed height.
Once clocked correctly, I welded it back on:

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Doing this required removing the wiring strap, and of course the retaining push star washer broke in doing so. I didn’t have any replacements, so we improvised and threaded a very small Nyloc nut down onto the stud to retain it.

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Not ideal, but it’s secure, and not going to come off. From there, it was time to install the modified pickup with the new O-ring and locking collar that came with the tank.

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The next issue that reared its ugly head was that during my haste in installing the Aeromotive assembly, I hadn’t yet fully tightened it down to the tank. No big deal until I discovered that by doing so it brought the return line fitting so close to the top of the tank that it was no longer possible to get the hose installed onto it.

As much as it pained me to do so, out came the ball peen hammer and a couple of brass drifts to clearance the top of the tank.

Saving grace is that this is on the top of the tank, and will never be seen. Even with the Aeromotive assembly now fully tightened down, there’s still lots of room for both the fitting into the assembly, and the hose end.

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Last order of business before reinstalling the tank, was to remove the 90 degree elbow from the filler neck, and to install a hex head plug in its place to seal it up again.

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One final look at the stock pickup assembly now fully installed. Unfortunately I wasn’t able to progress with the vents at this point, the rollover valve is late on delivery, and I don’t have any of the hose I want to use on the pickup vent anyways. Those will both have to wait until sometime next week when I get the necessary parts.

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We chose not to install the new heavy duty wiring kit just yet either, it’s only two connections on the top of the tank, and all that wiring will just be dangling and in the way until I get to the wiring aspect on the car anyways.

All for now guys, I’ll update again when I finally get all the vent components to complete the install.

D.
 
Please post how you remedy that gas filler pipe, Donovan, I have the same one in my basement to install soon. 👍

Done and done, in the update above ^^^ Mike.
 
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Reactions: Tony1968
Make sure you sign the top of the tank, date it, and put a couple words of wisdom to the Planet of the Apes people that find this relic 300 years from now or whatever...leave a legacy. 🙂

This car is my legacy. May it live on long after I’ve returned to dust.
 
Jinkies, I have a Spectra tank that the filler is too high. I guess I’ll give it a yank and see what happens 😉

Just kiddin’, I’m living with it for a little bit.
 
Jinkies, I have a Spectra tank that the filler is too high. I guess I’ll give it a yank and see what happens 😉

Just kiddin’, I’m living with it for a little bit.

I would at least try. I think you would be surprised at how easily it moves.
 

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