gas sending unit

[longtops]

Im in need of information on a gas gauge sending unit for my 50 Coronet Is it possible to find one at the local parts store.I have checked the dash gauge so I'm almost positive its the sender Thanks.

[TodFitch]

http://www.ply33.com/Repair/fuelsender.html

[48mirage]

I followed the instructions in the link above and even though my results are not 100% perfect, I am very happy with the results. P.S. I blame my less than 100% results on my craftsmanship.

[BobT-47P15]

Roberts Motor Parts is supposed to have an Atwater Kent unit.....last price

I heard was around $88

http://www.robertsmotorparts.com/car_parts.asp

The last phone number I had for the Atwater Kent company, who makes

a nice sending unit for Plymouths - with two wires...cost about $115....

(508)792-9500.

Far as I know, if you have a Plymouth you need a two wire sender.

Dodge takes one wire.

[aero3113]

My 50 Plymouth is 1 wire

[BobT-47P15]

Hmmm.....OK.....they changed to one wire at some point....

anyone know which year??? Maybe 49 second series? The 46-early 49s have two wires...at least

the ones I've seen.

Based on that, then, maybe one of the single wire units sold by Whitney

for about $20 would work.

[Plymouthy Adams]

not all early 49's were two wire..that is the first big difference I have a 2 stock clusters with two wires and 1 stock cluster with a single wire to the sender.

[BobT-47P15]

Interesting......perhaps one of those mid-year sort of changes, even if

the early 49 had a short year.

[TodFitch]

Near as I can tell, Plymouth gas gauges are as follows:

1928-29 (Q and U): Mechanical gauge mounted on tank (have to walk to rear of car to see how much gas you have).

1930-1938 (30-U through P5,P6): Single wire unit. Full around 0 to 5 ohms, empty around 120 ohms based on my dash unit.

1939-48 (P7,P8 through P15): Two wire units.

1949-??: (P17 and newer) Single wire units. 10 Ohms to 78 Ohms. I know that my 63 had a one wire unit. Don't know what the resistance range was...

Some of this is a guess as I have not found specifications for the resistance of the early one wire units and the part numbers change for every year. Two wire versus one wire is based on wiring diagrams in the factory service manuals.

[BobT-47P15]

Now.....the next question that comes to mind......how similar are the gas

tanks from, say, 1940 to mid 50s on Plymouths??

In other words, would either an earlier or bit later tank fit properly on a

46-48 P15? Is the hole for the float in the same location....do the filler

necks match up.....gas line connect in same location?

I would think the physical size would be similar.

Any info on that?

[Young Ed]

I know by 51 the plymouth used the more modern style of sender system that is held in by a rotating lock ring. They also had done away with that odd style of fuel line that needed that ferrule piece.

[aero3113]

My 50 has the lock ring also

[bubba1941]

Near as I can tell, Plymouth gas gauges are as follows:

1928-29 (Q and U): Mechanical gauge mounted on tank (have to walk to rear of car to see how much gas you have).

1930-1938 (30-U through P5,P6): Single wire unit. Full around 0 to 5 ohms, empty around 120 ohms based on my dash unit.

1939-48 (P7,P8 through P15): Two wire units.

1949-??: (P17 and newer) Single wire units. 10 Ohms to 78 Ohms. I know that my 63 had a one wire unit. Don't know what the resistance range was...

Some of this is a guess as I have not found specifications for the resistance of the early one wire units and the part numbers change for every year. Two wire versus one wire is based on wiring diagrams in the factory service manuals.

Do you know the resistance for a 48 P15 sending unit? I need one, but of course it is a 2 wire one. Would like to locate a good used one. I'm new at this and this is my first attempt to communicate.. Hope it works. Thanks.

[aero3113]

I just ordered the modern sender, I will let you guys know how it turns out

[TodFitch]

If u ordered the Whitney one, some work may be needed. You will find that it has the 5 mounting screw holes used on the earlier vehicle tanks. Not a big deal.

You may also find to outside diameter to be a bit larger.

Bob Amos wrote up a procedure for fitting that universal one into a 1950s Plymouth. He gave me permission to republish it and my copy is posted at:

http://www.ply33.com/Repair/fuelsender.html

[aero3113]

I plan on using his instructions

[grey beard]

I've waded through this myself, and used Bob's writeup. He was just a little vague on exactly how he got the new sender to work with the old sender top disc. Here's what worked for me: salvage the disc from the old sender and clamp it together with the new sender disc. Then use the rectangular hole in the new disc as a pattern to file out the original hole in the old disc.

This all sounds much more complicated than it really is. You will need the old disc to fit the tank hole and the bayonet retainer ring. The other part of the job is getting the insulating washers in place correctly. When you are finished, the mounting disc must be grounded to the sender arm and the insulated wire circuit must still be insulated from the disc. That's as hard as the job gets.

One other note. I had my dash gauge on the bench with my sender and had everything wired up just like the schematic, but the gauge would not work properly. I finally figured out that the sender top disc must be gounded to the dash gauge base for the thing to operate. This ground path of the circuit is not shown on the schemtic - just understood, I suppose. Of course, I'm the sort of guy who learns VERY slowly . . . . . . go figure.

[aero3113]

Ok sounds easy enough, I should receive the new sender this week. Ill keep you guys posted.

[aero3113]

I received the sender today and made it fit the Plymouth in about 1 1/2 hours. Not that hard to make work. I did it a little different than Bobs procedures, I ground the new sender to fit in the original disc and also ground the original disc hole like grey beard said. I did not have to use any of the original insulation. I installed it and it was indicating perfect. Here are some pics.

[Fluid drive]

The last sender I replaced came from a company that advertises in Hemmings . It is solid state and a perfect replacement. I think it cost less than $100 and I believe it is guaranteed for life. The guy on the phone even knew what size the flange was and how many holes were in it. Sorry I can't find the receipt but I am sure Hemmings ad people could help there.