86 suburban fuel tank ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Artie in Miami · 02-08-2021, 12:35 PM

I am replacing my gas tank in 86 Suburban R20 (rust)...drained the tank...loosened the straps...jack under tank. Cannot get tank low enough to remove the fuel lines, filler hose etc on top of tank...filler hose is preventing lowering tank. Any thoughts/tricks I should know about ? The tank is HUGE...must be 35 or 40 gallons.

Ziegelsteinfaust · 02-08-2021, 12:47 PM

My G10 van is similar.

Un-do the filler neck, and that helps it slide down.

Or cut the filler hose to pull it out.

They are not easy

Artie in Miami · 02-09-2021, 12:16 PM

I thought about cutting the fill hose as I cannot remove the hose from the steel line coming from the fuel fill door. Yes...you are correct...this job is a BEAR !

**Corts60** · 02-12-2021, 02:45 PM

You must have the 40 gallon tank option. Let us know how it goes!

1976gmc20 · 02-12-2021, 11:32 PM

I had to do my 91 a couple times.

I did get the filler hose off one end or the other - can't remember which right now. It definitely is difficult to pull it off. Pretty sure I got it off the filler neck and left the other end attached to tank? Yeah, because I stuck a siphon hose directly down the hose to empty the tank.

As for the fuel lines, I loosened the straps and dropped the tank down a few inches. Might have to support the tank with jack, blocks, or a strap running from a frame crossmember near the axle and back to the trailer hitch. Anyway then I could with some difficulty reach in over the frame from the left wheel well and loosen the gas lines (TBI) with an open end wrench. Just takes patience as you can only turn about 1/8 turn at a time.

On mine it was a trick getting to clear the tailpipe and hangar, and of course after that you have to slide the tank sideways to left/driver to get the fill hose clear of the frame.

If you're replacing the tank and fill hose then you could just cut the darn thing

Putting it back in, I used the aforementioned strap to support and lift the tank until I could get the fuel lines and mounting straps connected. I just used a tow strap, hook on one end to the frame above the axle, under the tank, and then a half hitch around the trailer ball. I had my wife taking up the "belay" as I lifted and guided the tank from below.

I had the rear wheels up on my ramp timbers for more clearance.

roboticjunky · 02-13-2021, 12:50 PM

Have you tried taking the cover off inside of the Suburban to get to the filler hose.

Like in this pic.

Artie in Miami · 02-13-2021, 01:02 PM

Thanks for all the input guys...I finally got the filler hose off...using WD40 and channel locks ! Got the tank out, and found it was pristine inside !! The rust in the fuel filter is coming from the rusted 3/8" fuel line and pickup tube (on sending unit). Obviously, I need to replace the fuel line...what about the other two lines coming off the sending unit ? One is 5/16" and the other is 1/4"...do I need to replace those also ? What are these two lines for...is one a return and the other a vent or something. The 3/8" fuel line from sending unit to pump will not be tough to remove/replace...the other two will be a challenge...this beast has dual exausts/mufflers and the muffler heat shield hides some of the bolts that hold these two lines to the frame. The 3/8 fuel line goes on the outboard side of the frame...so it will not be a problem. These lines are probably rusted as well...and while I am down there, I could replace them (I think !!)...if I don't need to...I won't touch them !
Thanks again...this forum is the best !

Artie in Miami · 02-13-2021, 01:08 PM

And yes....it is a 40 gallon gas tank !! The guy that owned this truck before me ordered it with all the bells and whistles to tow his 25 foot boat...411 rear end, 4 bbl carb, dual exhausts, oil cooler, American Racing Mag wheels...after letting his wife driving it for about two years...he learned that she never had the oil or tranny fluid checked...engine was shot and tranny slipping...so...he bought a brand new engine (not rebuilt) and had tranny rebuilt...then bought a new truck and let this sit in the garage for a few years. Then I got it ! So it is worth repairing.

**Palf70Step** · 02-14-2021, 08:58 AM

If you are there and from what you said of the condition of the main line, I would do them all and make it solid for another 40ish years.

02-08-2021, 12:35 PM	#1
Artie in Miami Registered User Join Date: Dec 2019 Location: PALMETTO BAY Posts: 46	86 suburban fuel tank ? I am replacing my gas tank in 86 Suburban R20 (rust)...drained the tank...loosened the straps...jack under tank. Cannot get tank low enough to remove the fuel lines, filler hose etc on top of tank...filler hose is preventing lowering tank. Any thoughts/tricks I should know about ? The tank is HUGE...must be 35 or 40 gallons.

02-08-2021, 12:47 PM	#2
Ziegelsteinfaust Registered User Join Date: Dec 2012 Location: Temple City Posts: 3,628	Re: 86 suburban fuel tank ? My G10 van is similar. Un-do the filler neck, and that helps it slide down. Or cut the filler hose to pull it out. They are not easy

02-09-2021, 12:16 PM	#3
Artie in Miami Registered User Join Date: Dec 2019 Location: PALMETTO BAY Posts: 46	Re: 86 suburban fuel tank ? I thought about cutting the fill hose as I cannot remove the hose from the steel line coming from the fuel fill door. Yes...you are correct...this job is a BEAR !

02-12-2021, 02:45 PM	#4
Corts60 Just here to tinker Join Date: Jun 2008 Location: Holland, MI Posts: 3,697	Re: 86 suburban fuel tank ? You must have the 40 gallon tank option. Let us know how it goes! __________________ 78 C10 SWB Diesel #1 (wrecked)http://67-72chevytrucks.com/vboard/s...1978+silverado 78 C10 SWB Diesel #2 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=650751 60 GMC Suburban (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=445526 60 GMC 1000 (sold)http://67-72chevytrucks.com/vboard/showthread.php?t=298235 67 GMC 1500 (sold) http://67-72chevytrucks.com/vboard/s...d.php?t=803695 73 Chevy C20(Daily)http://67-72chevytrucks.com/vboard/s...d.php?t=852767 86 Suburban(summer unit) http://67-72chevytrucks.com/vboard/s...d.php?t=810697 88 Suburban 4x4(sold)

02-12-2021, 11:32 PM	#5
1976gmc20 Registered User Join Date: May 2015 Location: Montana Posts: 3,696	Re: 86 suburban fuel tank ? I had to do my 91 a couple times. I did get the filler hose off one end or the other - can't remember which right now. It definitely is difficult to pull it off. Pretty sure I got it off the filler neck and left the other end attached to tank? Yeah, because I stuck a siphon hose directly down the hose to empty the tank. As for the fuel lines, I loosened the straps and dropped the tank down a few inches. Might have to support the tank with jack, blocks, or a strap running from a frame crossmember near the axle and back to the trailer hitch. Anyway then I could with some difficulty reach in over the frame from the left wheel well and loosen the gas lines (TBI) with an open end wrench. Just takes patience as you can only turn about 1/8 turn at a time. On mine it was a trick getting to clear the tailpipe and hangar, and of course after that you have to slide the tank sideways to left/driver to get the fill hose clear of the frame. If you're replacing the tank and fill hose then you could just cut the darn thing Putting it back in, I used the aforementioned strap to support and lift the tank until I could get the fuel lines and mounting straps connected. I just used a tow strap, hook on one end to the frame above the axle, under the tank, and then a half hitch around the trailer ball. I had my wife taking up the "belay" as I lifted and guided the tank from below. I had the rear wheels up on my ramp timbers for more clearance. __________________ Current/past Chevy/GMC trucks: 1958 Chevy C-60; 1965 GMC C-50; 1965 Chevy C-10; 1971 Chevy K-10; 1973 Chevy K-20; 1976 GMC C-20; 1977 Chevy C-10 Suburban; 1980 Chevy K-10; 1989 Chevy K1500; 1991 GMC V1500 Suburban; 2016 Chevy K2500 HD Other vehicles: 1988 Jeep XJ; 2011 Toyota 4Runner

02-13-2021, 12:50 PM	#6
roboticjunky Registered User Join Date: Oct 2015 Location: IN Posts: 209	Re: 86 suburban fuel tank ? Have you tried taking the cover off inside of the Suburban to get to the filler hose. Like in this pic.

02-13-2021, 01:02 PM	#7
Artie in Miami Registered User Join Date: Dec 2019 Location: PALMETTO BAY Posts: 46	Re: 86 suburban fuel tank ? Thanks for all the input guys...I finally got the filler hose off...using WD40 and channel locks ! Got the tank out, and found it was pristine inside !! The rust in the fuel filter is coming from the rusted 3/8" fuel line and pickup tube (on sending unit). Obviously, I need to replace the fuel line...what about the other two lines coming off the sending unit ? One is 5/16" and the other is 1/4"...do I need to replace those also ? What are these two lines for...is one a return and the other a vent or something. The 3/8" fuel line from sending unit to pump will not be tough to remove/replace...the other two will be a challenge...this beast has dual exausts/mufflers and the muffler heat shield hides some of the bolts that hold these two lines to the frame. The 3/8 fuel line goes on the outboard side of the frame...so it will not be a problem. These lines are probably rusted as well...and while I am down there, I could replace them (I think !!)...if I don't need to...I won't touch them ! Thanks again...this forum is the best !

02-13-2021, 01:08 PM	#8
Artie in Miami Registered User Join Date: Dec 2019 Location: PALMETTO BAY Posts: 46	Re: 86 suburban fuel tank ? And yes....it is a 40 gallon gas tank !! The guy that owned this truck before me ordered it with all the bells and whistles to tow his 25 foot boat...411 rear end, 4 bbl carb, dual exhausts, oil cooler, American Racing Mag wheels...after letting his wife driving it for about two years...he learned that she never had the oil or tranny fluid checked...engine was shot and tranny slipping...so...he bought a brand new engine (not rebuilt) and had tranny rebuilt...then bought a new truck and let this sit in the garage for a few years. Then I got it ! So it is worth repairing.

02-14-2021, 08:58 AM	#9
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,225	Re: 86 suburban fuel tank ? If you are there and from what you said of the condition of the main line, I would do them all and make it solid for another 40ish years. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

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