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.

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

seventy2plus2 wrote:

---

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

---

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.

I routed through my notebook, and can't find where I thought I'd written down where someone repairs these canister sending units. I might take another look tomorrow.

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. 

 

 

 

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.

 

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.

"Ideas gladly welcomed"

The old 2+2 tank is not being reused.

You are welcome to take it apart to see what that sock looks like.

Back around 2003 when I worked at a Chrysler dealer there were issues with some models fuel gauges not working. It was due to crap building up on the variable resistor from modern fuels. MOPAR had an additive that did a good job restoring sending unit operation. You could see if it's still available. I also found a thread on another forum talking about a cleaner for sending units:

New 'clean' gasolines can cause fuel gauge malfunction

The Problem:
Certain residual sulfur species found at very low levels in many of todays highly refined gasolines can form corrosive deposits on reactive silver-based fuel sending unit (FSU) components used in many makes of automobiles. The FSU, located inside the fuel tank, reads the fuel level and electronically sends a signal to the fuel gauge.

How sulfur corrosion can cause your vehicle's fuel gauge to malfunction (false reading).
This corrosive deposit can disrupt the electrical performance of the FSU and lead to either erratic operation or complete failure of the FSU, often resulting in artificially low or high (empty or full) fuel level readings on the fuel gauge seen by the driver. An erroneous high (or full) fuel gauge reading could lead to the motorist inadvertently running out of fuel and create a potentially dangerous situation.

The problem is best viewed in medical terms: acute and chronic in nature

Acute: problems occur when the occasional batch of off-specification, high sulfur refinery gasoline leads to extensive erratic FSU operation across a region. The problem can occur in a single tank of gas.
Examples: Louisiana, Florida, Memorial Day, 2004; Erie, PA, Louisville, KY, Canada

Chronic: problems occur after long-term exposure to low-grade sulfur contamination in a fuel, which frequently leads to premature erratic behavior of the FSU at some point.
Examples: New Mexico and Arizona, 2004 and 2005

Higher temperatures play a vital roll in how severely an FSU is damaged by a harmful sulfur-containing gasoline.

FSU failures typically require the complete replacement of the sending unit at considerable expense to either the vehicle manufacturer or the vehicle owner. This repair can cost from $400 to over $1000.

There is strong automaker awareness, as virtually all automakers have been impacted: recalls, warranty repairs, safety concerns and product reputation. Some automakers are beginning to phase out reactive silver-based FSU components at significant expense. However, reactive silver-based FSU components have been used since the late 80's, so a 15 year-plus vehicle population is still exposed.

The Solution:
TECHRON® Concentrate Plus is one of the most advanced fuel system cleaning technologies available in today's market, and many automakers prescribe it routinely as their solution to all fuel deposit-related driveability problems.

One treatment with TECHRON® Concentrate Plus can help:

Clean corrosive sulfur deposits from fuel gauge sensors
Restore operation of sulfur contaminated fuel gauge sensors
Prevent harmful sulfur species from attacking sensitive electronic fuel sending units
Protect the FSU against malfunction by coating all metal surfaces of the fuel system
To meet your specific needs, there are two sizes of TECHRON® Concentrate Plus:
20 oz. #65740 - Treats up to 20 gallons of fuel and is designed for larger cars, light-duty trucks and sport utility vehicles.
12 oz. #67740 - Treats up to 12 gallons of fuel and is designed for smaller cars.

Thanks Mark. Having not taken one apart that was sticking I presumed maybe the overall size of the puck had swollen and it would be jammed against the side of the canister.