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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Mike Phillips on September 16, 2013, 08:30:40 am

Title: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Mike Phillips on September 16, 2013, 08:30:40 am
1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On


Last couple of times I drove my truck I thought I smelled gas?  This morning after driving to work, again I smelled gas so I started looking around and found the leak.  When looking down on the gas tank, in-between the cab and the bed, I could see fresh gas.

If I turn on the key, I hear the fuel pump, (inside the gas tank), working and then I see gas seeping out onto the top of the gas tank.  Here's a few pictures to show the location and the leaking gas.

(http://www.showcargarage.com/gallery/files/1/Leaking_Gas_Tank.03.jpg)

(http://www.showcargarage.com/gallery/files/1/Leaking_Gas_Tank.04.jpg)

(http://www.showcargarage.com/gallery/files/1/Leaking_Gas_Tank.05.jpg)

I've never removed a gas tank out of a truck this new.  I've removed the gas tank in my 1975 Jimmy, it was in the back of the frame. 


Question?

Has anyone removed a gas tank like this before and do you have any idea what it could be that is broken or leaking so as to be pumping gas out of the top of the tank?

Ugh...

:)
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: spanky1205 on September 16, 2013, 08:49:42 am
My first thought would be to check the fittings that go into the top of your tank.  They are probably leaking while under pressure but stop when the pressure is turned off.  FWIW I have heard it is easier to remove the bed from the pickup rather than trying to drop the tank.  Personally the only fuel tank I have ever worked on was in a car, after doing that I will be trying the bed option if I do anything to the fuel tank in my truck.
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: zieg85 on September 16, 2013, 09:03:01 am
Let me go out and take a picture of what you will find on your 87 BRB
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: zieg85 on September 16, 2013, 09:13:11 am
Here is what you will find.  Could be a hose, connection or even a crack in a rusty line that is built in the sending unit assembly.  Dropping the tank underneath isn't that bad since you are higher than a normal truck, just get the gas level down as low as you can before lowering...
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: rich weyand on September 16, 2013, 09:57:25 am
Yup.  And while you are in there, you might as well replace all three hoses over to the other side as well as the hose clamps.  These hoses cross over both exhaust pipes getting to the tank selector on the passenger side frame rail.

Note the double clamp on the high-pressure fuel line.

Once the tank is down, you should be able to cap the end of the fuel line and then power the fuel pump long enough to see where the leak is.  That may tell you that you need to replace the sender unit as well.
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Mike Phillips on September 16, 2013, 10:26:42 am
Hey thanks everyone for all the quick input...

Here's the picture of the top of the tank by zieg85, I uploaded it to my gallery so I could insert it...

(http://www.showcargarage.com/gallery/files/1/top_of_gas_tank.jpg)

Ding dang... I just filled this truck to the top so it's completely full of gas.

Taking the bed off almost sound more inviting.  One thing I've learned about this truck since I bought it.  Although the previous owner did do a lot of great upgrades, it does look like it was re-assembled using old, worn out parts.  Like the belts and hoses for example.  I think it's safe to assume most of use on this forum replace everything when we rebuild a truck.  I mean heck, while it's all apart it only makes sense.

Being Monday, I won't have a chance to tear into this until Saturday, so I think I'll cross my fingers, drive it home and borrow the wifey's car the rest of the week. 

Ugh again...


:D
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Mike Phillips on September 16, 2013, 10:29:10 am
Let me go out and take a picture of what you will find on your 87 BRB


Thank you sir!

That helps a lot.  Now I know at least what everything looks like.

The gas gauge doesn't read correctly since I bought this truck.  When full it's just below the 1/2  mark on the gauge and when empty it's just above the 1/4 mark on the gauge.

Guess it's time to look into this also.


:)
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: rich weyand on September 16, 2013, 10:58:45 am
Sounds like a broken resistor on the back of the fuel gauge. 
http://secure.classichq.com/RESISTOR-CONSOLE-FUEL-GAUGE--P816.aspx
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: 454Man on September 16, 2013, 07:40:21 pm
Dude your truck looks Awefrikinsome! Hope you don't mind me asking. What wheel and tire combo that is?

What's under the hood??? If you have to ask maybe we shouldn't race...

Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Mike Phillips on September 17, 2013, 07:47:38 am
Dude your truck looks Awefrikinsome! Hope you don't mind me asking. What wheel and tire combo that is?

What's under the hood??? If you have to ask maybe we shouldn't race...

Thank you.  What's even better is my wife Stacy found it for me.  Got love it when your wife finds you your new truck.

I'm a total big block Chevy guy but this thing came with a 350 and it runs so darn good it's a shame to have to remove it and replace it with a BBC but that's what's on the menu.  Just have to wait till spring/summer of 2014, too much going on in life to do it right now.

See this thread...

http://forum.73-87chevytrucks.com/smforum/index.php?topic=26508.0


:)
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Mike Phillips on September 19, 2013, 11:28:34 am
Looks like I'm unbolting the truck bed starting Saturday morning.

I'll take some pictures in-case anyone else ever has to do this type of project into the future.


:)
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: rich weyand on September 19, 2013, 01:10:19 pm
One good part of taking the bed off: you can test it in place.  Just turn the key on and track the leak down.
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: frotosride on September 19, 2013, 07:37:44 pm
I haven't had my bed off in over a year but it sure spins the tires wthout that weight on them. I think that I had a car port at the time so I just took out the light and placed on old jack pole over it with a come along... Thinking back..man was I lucky!
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Mike Phillips on September 20, 2013, 08:37:48 am
One good part of taking the bed off: you can test it in place.  Just turn the key on and track the leak down.

That's a good point.

I looked under the bed, looks like an air wrench will make quick work of removing the 8 nuts that hold the bed on.  Haven't looked to see what I have to do to remove, loosen or unplug any wiring loom.

Someone said to make it easier to remove the rear bumper, I'll look into that too.

Supposed to be sunny tomorrow so I'm going to start in around 8:00am

Wish me luck!

:)
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Irish_Alley on September 21, 2013, 12:02:38 am
you should only have to un-bolt the fuel nozzle there might be a ground also (on my 94 there was) then a plug under the tail gate for the tail lights along with the bed bolts. the bumper i never took it off but either way you have to lift the bed up enough to clear the tires. dont have to remove it all the way just a couple feet back and let her rest on the bumper and tires. this is what i did with my 94
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: frotosride on September 21, 2013, 04:37:22 pm
Based on the fact that it is on the actual frame I would say that it is most likely coming from the hoses either at the sending unit itself of the actual hoses themselves. It is not uncommon for someone to do such a nice build and overlook the items most needed. Right on the frame is a metal hold down and there isn't any protection for the hoses that pass through it. It is very possible for it to have rubbed a hole in a hose. Just a little FYI if you feel like it you can switch the hoses around on the switch to pump the full tank into the other one if you have dual tanks. Thought you said you did. Or you can take the outlet off of the  pump and put it into a bucket. then lowering the tank would be much easier.
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Captkaos on September 23, 2013, 09:11:33 pm
Being a short bed, you will need to pull the bed to have the best access, Or you can drop the tank...

http://forum.73-87chevytrucks.com/smforum/index.php?topic=9294.0
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Mike Phillips on September 24, 2013, 09:06:28 am
Here's a follow-up...

Removed bed, removed gas tank, installed Super Hoops bracket for Super Hoop because gas tank was in the way.  Found the fuel lines were completely corroded and cracked and replaced these.  Put everything back together and took my truck to the local car show that night.  Started at 9:00am, finished at 5:00p.  Got a little sunburned...

(http://www.showcargarage.com/gallery/files/1/Leaking_Gas_Tank.06.jpg)

(http://www.showcargarage.com/gallery/files/1/Leaking_Gas_Tank.07.jpg)

(http://www.showcargarage.com/gallery/files/1/Leaking_Gas_Tank.08.jpg)

(http://www.showcargarage.com/gallery/files/1/Leaking_Gas_Tank.09.jpg)

(http://www.showcargarage.com/gallery/files/1/Leaking_Gas_Tank.10.jpg)



My buddy Dave came by with Behemoth to see if I needed any help...

(http://www.showcargarage.com/gallery/files/1/Leaking_Gas_Tank.11.jpg)



These fuel lines look original by the degree of breakdown in the rubber...

(http://www.showcargarage.com/gallery/files/1/Worn_Out_Fuel_Line.01.jpg)

(http://www.showcargarage.com/gallery/files/1/Worn_Out_Fuel_Line.02.jpg)

(http://www.showcargarage.com/gallery/files/1/Worn_Out_Fuel_Line.03.jpg)

(http://www.showcargarage.com/gallery/files/1/Worn_Out_Fuel_Line.04.jpg)


Sad to say, I didn't have time to clean up and detail anything, tank, frame, front of bed, back of cab.  I have co-workers working till 4:00pm and I had to hustle to be ready to take advantage of these guys to help me lift and replace the bed back onto the frame.  Had I done other things I would have been in a jam.  Now that I've done this and all the bolt threads are cleaned and oiled, it will be a lot easier to remove in the future for any future projects.

Thanks for all the help guys!


:)
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: frotosride on September 24, 2013, 07:18:54 pm
Glad you got her up and running...just proof that rubber doesn't last for ever. Good to have a helping pair of hands.
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Captkaos on September 25, 2013, 09:31:57 pm
And E85 and Ethanol is going to do that to the inside eventually...
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: frotosride on September 25, 2013, 11:33:05 pm
And E85 and Ethanol is going to do that to the inside eventually...

For a while I didn't think about the fact that Ethanol is in every grade of gas now adays and finding pure gas stations is harder and harder. Maybe it's rubber manufactures' way of generating more income...it's working!
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Mike Phillips on June 17, 2015, 02:54:23 pm


Sounds like a broken resistor on the back of the fuel gauge. 

http://secure.classichq.com/RESISTOR-CONSOLE-FUEL-GAUGE--P816.aspx



Yesterday I removed the dash pad and then removed the instrument gauge cluster in order remove the speedometer cable so I can install a new speedometer cable.

Right now while the dash is all apart, are you saying I need to order this part and then somehow it can be attached on the back of the circuit board to make the fuel gage read correctly?

(http://secure.classichq.com/Assets/ProductImages/w-586a.jpg)

This is new stuff to me.

:)
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Irish_Alley on June 17, 2015, 05:27:21 pm
http://forum.73-87chevytrucks.com/smforum/index.php?topic=31156.0
Probably should test parts if you haven't to make sure its bad
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: rich weyand on June 18, 2015, 12:18:52 pm
Yeah, there's one of those on the back of the fuel gauge already.  From the symptoms you describe, it sounds like it is either busted or not making contact.  You can try just jiggling it around and see if that changes the reading once you have contact.  You can also remove the resistor and test it with an ohmmeter to see if it is broken or not.  I put external-tooth star washers on mine to make better contact.
Title: Re: 1987 Chevy Silverado 4x4 - Leaking Gas out the top of the Gas Tank with Key On
Post by: Don5 on June 18, 2015, 11:31:19 pm
Good job tracking down the hoses. I agree that most people tend to overlook stuff like that. It's the little details that really make the truck. I noticed that you have traction bars on the back. Do you like those or are you taking them off when you do the shackle flip?

 Reason I am asking is that I have a set but I am on the fence about bolting them on. I think something will break if I bolt them on and take the truck out into the mud. I am thinking the flex might be an issue. They would be OK for straight line though. I am really interested in hearing your response.