New float assembly now gas gauge won't work - The 1947 - Present Chevrolet & GMC Truck Message Board Network

67GMCcampercruiser · 09-25-2019, 01:06 PM

I installed a new gas tank float assembly. Gas gauge shows empty but when I pull the wire off the tank the gauge goes up. Does the float assembly need to be grounded some how?

**Joesjunk** · 09-25-2019, 06:59 PM

Quote:

Originally Posted by 67GMCcampercruiser

I installed a new gas tank float assembly. Gas gauge shows empty but when I pull the wire off the tank the gauge goes up. Does the float assembly need to be grounded some how?

Sounds like the new float has a crack in it. I have had this problem before with brand new ones.

When you pull the wire off the needle will point to the right.

71meangreenc10 · 09-25-2019, 07:21 PM

If you bought a brass one, throw it in the trash and replace it with this. Never look back...

Smitty

http://67-72chevytrucks.com/vboard/s...d.php?t=666161

67ranchhand · 09-25-2019, 08:56 PM

I bought a brand new one in March. Guage quit working in August. Pulled it back out and the brand new brass float had a crack in it and was full of fuel. Summit sent me a new one, free of charge, but I think I will get one of those plastic floats to have on hand. Brass float seems to be problematic.

71meangreenc10 · 09-25-2019, 09:08 PM

Quote:

Originally Posted by 67ranchhand

I bought a brand new one in March. Guage quit working in August. Pulled it back out and the brand new brass float had a crack in it and was full of fuel. Summit sent me a new one, free of charge, but I think I will get one of those plastic floats to have on hand. Brass float seems to be problematic.

Brass ones have been junk for a long time. I only use the plastic ones and have them on hand. Picked up a truck a month ago and it had a new sender with a bad float. Usually the solder is the problem.

Smitty

67GMCcampercruiser · 09-25-2019, 10:18 PM

Good advice! Thanks

External · 09-27-2019, 10:39 AM

I'm about to install my 3rd replacement sending unit.
All of the brass floats I pulled out were not full of gas.
I will also get the plastic float.
But I have to ask, is there a procedure for hooking up the wire?
Should I ground it out first?
I'm disconnecting the battery first.
I have installed 2 new sending units and both work for one day.
Kinda wondering if my luck is that bad.
I ordered them from the truck and car shop.
Any advice is much appreciated.

Still sitting on empty

71meangreenc10 · 09-27-2019, 05:26 PM

I have never had to add a ground to a fuel sender. Make sure your wire from the sender to gauge is not pinched anywhere down the body. There have been a few that have bad resistors on the back of the cluster, but I have never had that.

Mine have had fuel in the floats.

When you ground the wire with the key on the needle should peg out on full, when released, it goes back to empty.

Smitty

demian5 · 09-27-2019, 06:12 PM

I had a problem like this and my plumber friend brazed it up.

There must be a ground from the body to the sending unit.

67ranchhand · 09-27-2019, 08:26 PM

Quote:

Originally Posted by External

I'm about to install my 3rd replacement sending unit.
All of the brass floats I pulled out were not full of gas.
I will also get the plastic float.
But I have to ask, is there a procedure for hooking up the wire?
Should I ground it out first?
I'm disconnecting the battery first.
I have installed 2 new sending units and both work for one day.
Kinda wondering if my luck is that bad.
I ordered them from the truck and car shop.
Any advice is much appreciated.

Still sitting on empty

Take an ohmmeter and make sure the sending units are, or aren’t, working properly. Hard to believe all three of them are bad. Not saying it isn’t possible, with the quality of some of the aftermarket parts.

BigBird05 · 09-27-2019, 09:21 PM

The service manual shows a ground on the gas tank unit.

**HIGHWAY BY THE SEA** · 09-30-2019, 06:43 PM

This has happened to me twice with my 68. The first time it was the sending unit's float arm. I tied a string to it and lowered the gas sending unit into the gas tank, then pulled the string. It went, "CLANK CLANK CLANK" because the float arm needed to be bent so that the float did not hit the gas tank walls. I bent it, and it has worked properly ever since. The second time it was a cracked brass float that I replaced.

Happy_dan · 10-01-2019, 08:30 AM

Gee, this makes me think maybe rebuilding a carb I should a plastic float too. Could be a similar situation?

09-25-2019, 01:06 PM	#1
67GMCcampercruiser Registered User Join Date: Sep 2017 Location: Riverton, Manitoba Posts: 67	New float assembly now gas gauge won't work I installed a new gas tank float assembly. Gas gauge shows empty but when I pull the wire off the tank the gauge goes up. Does the float assembly need to be grounded some how?

09-25-2019, 07:21 PM	#3
71meangreenc10 Its a Truck Thing...... Join Date: Dec 2004 Location: Sierra Vista, Arizona Posts: 3,179	Re: New float assembly now gas gauge won't work If you bought a brass one, throw it in the trash and replace it with this. Never look back... Smitty http://67-72chevytrucks.com/vboard/s...d.php?t=666161 __________________ 71 C10 283/3SPD Full Resto 71 GMC 1500 Sierra Grande http://67-72chevytrucks.com/vboard/s...d.php?t=518599 70 C10 Suburban Former military GSA truck. 72 Chevy Blazer 4X4, Sloppy Jo, Mountain Climber. Wife says no more trucks. http://67-72chevytrucks.com/vboard/s...d.php?t=707378 72 GMC 1 Ton Motor Home, wife said no more trucks until she saw this one. Gen 3 6.0/4L80E 4.10 http://67-72chevytrucks.com/vboard/s...d.php?t=761110 68 GMC Suburban was 3/4 ton, now 1/2.Wife shook her head 71 C30 Wrecker 71 C20 Scott-Bilt As weird as it gets..BB Cheyenne AC Truck 68 GMC Long Stepside. They keep following me home 69 C30 Former Motor Home, Flat Bed time 70 G20 Red-E-Kamp Conversion "I'm your Boogy Van"

09-25-2019, 08:56 PM	#4
67ranchhand Registered User Join Date: Oct 2018 Location: Tiffin Ohio Posts: 74	Re: New float assembly now gas gauge won't work I bought a brand new one in March. Guage quit working in August. Pulled it back out and the brand new brass float had a crack in it and was full of fuel. Summit sent me a new one, free of charge, but I think I will get one of those plastic floats to have on hand. Brass float seems to be problematic.

09-25-2019, 10:18 PM	#6
67GMCcampercruiser Registered User Join Date: Sep 2017 Location: Riverton, Manitoba Posts: 67	Re: New float assembly now gas gauge won't work Good advice! Thanks

09-27-2019, 10:39 AM	#7
External Registered User Join Date: Jun 2018 Location: Louisiana Posts: 185	Re: New float assembly now gas gauge won't work I'm about to install my 3rd replacement sending unit. All of the brass floats I pulled out were not full of gas. I will also get the plastic float. But I have to ask, is there a procedure for hooking up the wire? Should I ground it out first? I'm disconnecting the battery first. I have installed 2 new sending units and both work for one day. Kinda wondering if my luck is that bad. I ordered them from the truck and car shop. Any advice is much appreciated. Still sitting on empty __________________ '72 Chevy Custom Deluxe Highlander. Med Olive/White 350/200 ps,pb and Air Conditioning!

09-27-2019, 05:26 PM	#8
71meangreenc10 Its a Truck Thing...... Join Date: Dec 2004 Location: Sierra Vista, Arizona Posts: 3,179	Re: New float assembly now gas gauge won't work I have never had to add a ground to a fuel sender. Make sure your wire from the sender to gauge is not pinched anywhere down the body. There have been a few that have bad resistors on the back of the cluster, but I have never had that. Mine have had fuel in the floats. When you ground the wire with the key on the needle should peg out on full, when released, it goes back to empty. Smitty __________________ 71 C10 283/3SPD Full Resto 71 GMC 1500 Sierra Grande http://67-72chevytrucks.com/vboard/s...d.php?t=518599 70 C10 Suburban Former military GSA truck. 72 Chevy Blazer 4X4, Sloppy Jo, Mountain Climber. Wife says no more trucks. http://67-72chevytrucks.com/vboard/s...d.php?t=707378 72 GMC 1 Ton Motor Home, wife said no more trucks until she saw this one. Gen 3 6.0/4L80E 4.10 http://67-72chevytrucks.com/vboard/s...d.php?t=761110 68 GMC Suburban was 3/4 ton, now 1/2.Wife shook her head 71 C30 Wrecker 71 C20 Scott-Bilt As weird as it gets..BB Cheyenne AC Truck 68 GMC Long Stepside. They keep following me home 69 C30 Former Motor Home, Flat Bed time 70 G20 Red-E-Kamp Conversion "I'm your Boogy Van"

09-27-2019, 06:12 PM	#9
demian5 Registered User Join Date: Aug 2016 Location: Lake Forest, CA Posts: 2,177	Re: New float assembly now gas gauge won't work I had a problem like this and my plumber friend brazed it up. There must be a ground from the body to the sending unit. __________________ "Work hard, use your vacation days." 1970 C15 GMC Long Bed 1986 C20 Scottsdale 1983 K2500 Sierra Classic Suburban 6.2 Instagram: C10sofOC

09-27-2019, 09:21 PM	#11
BigBird05 Registered User Join Date: Aug 2019 Location: Cheraw Posts: 1,300	Re: New float assembly now gas gauge won't work The service manual shows a ground on the gas tank unit.

09-30-2019, 06:43 PM	#12
HIGHWAY BY THE SEA Senior Member Join Date: Nov 2012 Location: BY THE CAROLINA SEA Posts: 922	Re: New float assembly now gas gauge won't work This has happened to me twice with my 68. The first time it was the sending unit's float arm. I tied a string to it and lowered the gas sending unit into the gas tank, then pulled the string. It went, "CLANK CLANK CLANK" because the float arm needed to be bent so that the float did not hit the gas tank walls. I bent it, and it has worked properly ever since. The second time it was a cracked brass float that I replaced. __________________ FRANKENTRUCK 1981 Chevrolet C10 Shortbed Stepside GRANDTRUCK 1968 Chevrolet C10 Stepside Longbed http://67-72chevytrucks.com/vboard/s...d.php?t=584617 PROJECT JIGSAW 1967 GMC C3500 GREAT WHITE 1986 Blazer M1009 454 engine w/700R4 transmission gas conversion

10-01-2019, 08:30 AM	#13
Happy_dan Registered User Join Date: Jul 2019 Location: New Boston, NH Posts: 456	Re: New float assembly now gas gauge won't work Gee, this makes me think maybe rebuilding a carb I should a plastic float too. Could be a similar situation? __________________ 1968 C-20 CST Vermillion http://imageevent.com/happy_dan/dantoys/68c20 2019 Silverado 2012 Camaro ZL1

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