Fuel Sending Unit

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NicolasB
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Years Owned: 1969 Oldsmobile Toronado

Fuel Sending Unit

Postby NicolasB » Tue May 25, 2021 5:39 pm

Hey guys, so I finally took down the fuel tank on my ‘69 Toronado to remove the rust and fix the fuel sending unit, but I noticed that the sending unit is sealed with a metal cylinder. I tried to pry it off, but it doesn’t budge. Is there any way to take it out and access the internals, like the float, etc.? Thanks!
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NicolasB
Posts: 261
Joined: Sat Apr 25, 2020 9:27 pm
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Years Owned: 1969 Oldsmobile Toronado

Re: Fuel Sending Unit

Postby NicolasB » Tue May 25, 2021 11:08 pm

Interesting, so I found out on another forum (for a different Oldsmobile) that the inside of the fuel sending unit has a hockey puck-styled float which slides up and down the canister to read the fuel level. A pretty unique and cool design…which I heard can get stuck quite often since there’s little clearance between the puck float and the canister.

https://classicoldsmobile.com/forums/pa ... lp-136291/

After thinking about it (and doing a bit of research online to confirm my thought-process), the purpose of the canister is to prevent any unnecessary fuel from sloshing into the float, which could cause the gauge reading to fluctuate during inclination, hard acceleration or braking, etc. (small holes around it to let the fuel escape slowly). Now, the original tank does have one baffle, but if I replace it with a new sending unit that is exposed, the chances of the gauge moving around is more probable. It would kinda suck, but a working fuel gauge is better than one that reads full all the time.

I still might rebuild it, or just get a replacement from a ‘71-‘72 Toronado/Buick Le Sabre (same part). I heard that it fits for ‘68-‘69, just have to plug the second line and it (apparently) reads empty when the tank has 5 gallons left. I think you can adjust that by bending the rod that holds the float.

NicolasB
Posts: 261
Joined: Sat Apr 25, 2020 9:27 pm
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Years Owned: 1969 Oldsmobile Toronado

Re: Fuel Sending Unit

Postby NicolasB » Tue May 25, 2021 11:37 pm

Thanks goodness we have the internet, I found two videos on how to repair these type of sending units!

https://youtu.be/fBdBw4ileyA

https://youtu.be/MJQUE2Mr1Q8

The first one is more in-depth and covers the technical stuff about the sending unit, while the second one is more of a quick-fix if it’s simply stuck. I’m going to test both methods, but I first need to find my multimeter :lol:

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Otto Skorzeny
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Re: Fuel Sending Unit

Postby Otto Skorzeny » Wed May 26, 2021 5:56 am

That video with the Tennessee hillbilly was pretty good. It would have been nice to know if the unit actually works. I guess we won't know until he finishes restoring the entire car.

Tuco
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Years Owned: 1966 Toronado
1951 Cadillac
1957 Pontiac
1965 Impala

Re: Fuel Sending Unit

Postby Tuco » Wed May 26, 2021 6:50 am

That’s odd. I’ve never seen one like that.

Mine wasn’t like that at all. But then again someone could have replaced it in the past. I got a sending unit on eBay for a 66 Eldo. It worked perfect.

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Otto Skorzeny
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Re: Fuel Sending Unit

Postby Otto Skorzeny » Wed May 26, 2021 7:42 am

I wonder if that was a change made to the later Toronados after '66-'67?

I've also never seen one like it but my experience with 60s and 70s GM cars is limited. That actually looks like a much better design, though.

Every other car I've ever had has the toilet tank style float.

NicolasB
Posts: 261
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Years Owned: 1969 Oldsmobile Toronado

Re: Fuel Sending Unit

Postby NicolasB » Wed May 26, 2021 7:53 am

In the service manual for ‘69, it shows a diagram of the B,C, and E body cars having the same style sending unit, so I was confused at first when I saw it since I didn’t take down the tank at the time. For sure, I’ll try to make this one work since it seems doable.

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Otto Skorzeny
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Re: Fuel Sending Unit

Postby Otto Skorzeny » Wed May 26, 2021 8:58 am

Do you mean the manual shows the toilet tank style float for all those cars or the canister type?

NicolasB
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Years Owned: 1969 Oldsmobile Toronado

Re: Fuel Sending Unit

Postby NicolasB » Wed May 26, 2021 10:50 am

Sorry, I meant the canister type. The A body didn’t have the canister one, just the typical “toilet tank” style.

I noticed that the top of the tank was leaking around the lock ring. Are there any replacements for the gasket/o-ring? Can’t seem to find one online.

NicolasB
Posts: 261
Joined: Sat Apr 25, 2020 9:27 pm
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Years Owned: 1969 Oldsmobile Toronado

Re: Fuel Sending Unit

Postby NicolasB » Wed May 26, 2021 4:31 pm

Okay never mind haha, I can’t fix this sending unit. Since the tank was dented from the bottom, it caused the canister to deform a bit so that the float can’t move at all (clearance is precise, kinda like a piston). I just bought one for a ‘72 Toro instead and will see what I can do with that return line it has. Rather have a gauge that moves a bit when going uphill than one that doesn’t work at all.


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