Well, we just have to find out now don't we...

This video inspired me in thinking.... it might be possible,

Seems a simple and clever design. The key here  is the can is an accumulator of gas, and as such isn't as susceptible to instant level changes in the tank. It has a couple of small holes in the can that bleed the fuel in and out slowly. One on the lower side, another on the bottom. The new style senders have the float moving up and down wildly as you stop, start  and turn. Sure, on a steady flat run, it calms down, but it's still erratic compared to the old style.

Probably the biggest roadblock to a proper repair, the sock. What do you use here. How do you configure or adapt something else in place.

The sock was very brittle, and basically crumbled when I removed it. I don't think there would be any other way to remove it without destroying it. Not sure how the retainer ring comes off. We'll see..

The outlet pipe is rusted. Not destroyed, but close. I suppose one could make up a new line and silver solder it onto better metal near the cut line shown.

Some numbers from the MPC from the old senders 65-70. Wagons, outlet size, one or two lines, depth (tank size) and maybe even the ohms could certainly vary.

I think 6428084 is this unit.

I'll open the can over the next little bit and see how it looks. If the variable resistor winding is intact, it could probably be made to work again. right now, I don't hear the float move, so it's probably stuck.

If I could do it, I'd take the tank down one more time to install a proper sender.

I just had to look inside.

The push nut retainer came off the downpipe fairly easy. The float was sticky on the pipe and resistor. But it slid off no trouble. All pretty clean the 55 years considered.

Don't know if the nut could be reused at this point, we'll see.

I'm seeing that Delphi has a bunch of different pump strainer socks listed all over on line. Seem common and many different shapes and sizes. Something along this line might be adaptable.

I've found a couple of Delphi socks showing the metal cup ID being .751". The original push on retainer has a OD of about the same. Somehow adapt, crimp, dimple that old retainer (or parts of it) into the new sock cup..

https://www.ebay.ca/itm/363955817798

I have the original canister sending unit from the 454 Laurentian in the garage. It was stuck at 3/8 full of I recall.
It has a 3/8" output line, and a 1/4" return line and I'd love to get it working again.
I think I saw someone in the US rebuilds them.

LT1Caddy wrote:

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Mark, Isn't there a tank/gauge repair place in the west end of Toronto?

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Thanks Bruce, it's likely, but I'd much prefer to do it myself. No fun in just sending it out. In fact, if I had to spend 2-300 bucks, I'll just live with the cheap replacement. Guys with the big numbers cars doing it I get.

It's a dead simple device, really just a matter of repairing that rusted output line, cleaning the resistor (provided the winding is still intact), the float contacts, checking the ohms up and down, then buttoning it up some way with an adapted sock. 

seventy2plus2 wrote:

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I have the original canister sending unit from the 454 Laurentian in the garage. It was stuck at 3/8 full of I recall.
It has a 3/8" output line, and a 1/4" return line and I'd love to get it working again.
I think I saw someone in the US rebuilds them.

-- Edited by seventy2plus2 on Tuesday 23rd of April 2024 07:45:10 PM

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Im with you Clint. Unfortunately, my sending unit was totally rusted out. I would definitely be interested in buying one if anyone has a used big block one like you have. My aftermarket one has worked fine for 12 years, but I dont like way the gauge needle moves around.

Think of all the old style senders that got pitched. Early on they probably only suffered from a stuck float. And at one time GM even made a replacement sock for them.

I'll at least give it a try but it looks pretty rough. I could easily add a new section to it, be it soldering or just using a double brass compression fitting.

As far as a repair place for this type sender, apparently the talk was over on the Chevy Talk form a while back, the fellow that did them folded the business.

Maybe someone else picked up the slack?

Im still convinced we can DIY these. 

Difficult,

• Repair a broken winding. Its superfine wire, wound I bet over 1000 times on what looks like a mica insulating card. 
• Replace a broken float. The contacts inside could be redone or repaired, but a crumbled float puck, you'd need another.
• Repair an excessively rusted or damaged top

Doable,

• Find an appropriate sock that can be easily adapted.
• Find an appropriate clip that can secure the can base, sides and the sock to the pickup pipe
• Repair a rusted output or input line.
• Replace the ground wire
• Repair the ground to resistor stud

So if I'm successful here, send me all the can type senders you can find and I'll start doing them lol!

It would be neat to see a dual line Clint. Be careful with that clip, we might need it.

Some detail,

The float looks like cork.

Contact bars and points, the brown cast on the bars is 100% fuel residue. It rubs off, but I want to be very gentle with these contacts. I'll try Deoxit spray with a wipe.  No bending.

Also the metal cap has some heft to it. Engineered weight for sure.

The float nests into the base

The ground contact strip has a texture when you look close,

The winding, 

Interesting. The windings are tight until 2" from the top where they get more spaced all the way to the bottom at 5". It's visible here.

Faster increase of the resistance curve for the first 1/3 of the tank, then slower to the bottom. Right, that tapered tank gets emptier faster as it drains. Zero at full, 90 at empty?

The connection from the gauge. The connector stud comes through a grommet into a steel strip that runs down the intake pipe.

Strip is insulated from the body by some kind of mica board trough on 3 sides. The winding circles it's own board and sits in the trough. 

In your photo showing the float nesting into the base, you're showing the bottom side of the base. 

Sometimes I forget how much stuff I have in the garage.   I found a selection of single line canister style sending units, plus these 4 dual line units:

Float Stuck:

Float moves, but has small dent (circled) in bottom edge from where the wrecking yard punctured the fuel tank:

From a 1970? Buick, much longer with straight fuel lines.   I pulled it apart years ago by breaking the canister apart.  The sock has been removed but bottom clip intact.  

And finally the original line from the 454 Laurentian.  It's float is stuck.

You'll notice in all of the above, the return line just dumps the fuel outside the canister.

Maybe i have it wrong

Yep, the metal base on the float contacts the can base at empty. Effectively creating an absolute zero ohm pathway.

Thanks Cint.

I tested the winding. 5" long, it's 94 Ohms at the top,

50 Ohms 2" from the top where the winding goes from tight wound to a little more open at the red arrow. When the float contact passes the red mark on the way down (1/2 a tank) the resistance curve flattens out a bit.

And near zero Ohms art the bottom, but effectively zero when the float contacts the can base completing the ground circuit.

Interestingly, when the float is at the bottom and contacting the can, you still effectively have about 1.25" of fuel still at the bottom of the tank.

So empty on the gauge gives you maybe 3 gallons of reserve.

The 24 gallon 1969 OEM tank is 6.25" deep from the sender flange to the bottom of the tank.

Sure can. Fixed the one in my '70 Catalina back in 2005. Easy fix. And it was terribly crusty. All along the same lines as posted here.

I think it was actually still working Randy, as found, the float was stuck at the top, and the gauge always read full ish.

But funny, that full mark had actually moved down just a tiny bit over the time I've owned it. I'm thinking the float probably got jarred down a wee bit a couple of times.

The resistor windings are measured good, so the biggest and really the only roadblock will be the strainer sock and how to mount it. There are probably a 1000 different designs out there. Just search fuel pump strainer on Amazon.

I do wish I had a mini lathe about now to make a brass fitting that could be sweated onto bottom of the intake pipe, to accept a Delphi strainer fitting.

Ideas gladly welcomed 

sounds good!

Thats very interesting, thanks Todd.

It certainly wouldn't hurt to add some of the treatment to your tank if you are running the oem sender. I remember all the trouble back in the early or mid 80's with the Chevy minivans and Petro Canada fuel. They were all loosing the gauge if they ran that fuel.

In looking at my unit, I feel the reason if "Failed" was that the cork seems to have swollen, and is pinching a little bit in the center where it slides up and down on the tube and resistor track.

Basically it was stuck up in the full position. Still sticky. A little file dressing to the sides of the slot where the track and pipe run should free it up.