Home » Public Forums » GMCnet » Here's one for the savvy.... (fuel lines)
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| Re: Here's one for the savvy.... [message #354219 is a reply to message #354217] |
Tue, 28 April 2020 13:16   |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Rich,
I feel particularly qualified to answer this, not just because I had my tanks down five times, but that is part of it.
The fuel sending unit gaskets seem to seldom be the issue. But, when you get the tanks down they are easy to update.
No matter when the fuel lines were replaced, if the line material was not alcohol resistant, then there you go. I also made this mistake with an early repair. I used rubber fuel line that I had kept in stock for a decade. Not only was it old already, but it only took about three years to go bad again.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Here's one for the savvy.... [message #354225 is a reply to message #354217] |
Tue, 28 April 2020 16:15 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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my experience on 2 coaches I have done myself, and helped with 4 others. is the 1st thing to leak is the tank vent. it is a fuel nipple, that gets a hose with hose clamp off it, and that hose that comes off at a little bit of a angle, so that connection tends to 1. crack 1st if old. and #2 might leak if it is a new hose and a hose clamp is not tightened enough. (new hoses will shrink just slighty, so you want to use really good clamps and tighten them well).
the chance of someone replacing part of the gas lines is very high. I have seen that a number of times, where they splice into hoses that they can reach and replace what they can short of removing the tanks, saving the problem of the hoses above the tanks for someone down the road later.
Like Matt said- the only times i Have seen senders leaking is when someone is not careful installing them. There is a lock ring, and the wrong mechanic pounding on that with a screw driver can mess that up. there is actually a tool for installing those lock rings, that allows even twist on it. but a careful mechanic can install them without the tool. I have seen 2 that someone looked like they installed it with a air chisel.
I am going to knock on wood- my coach that sat for 10 years and had all sorts of fuel line rotted off. and my friend Ed's coach, that also sat for 10 years. both have functioning fuel senders/pickups, and only needed new hoses. others have got into the project and found holes in the tanks, and bad senders, or worrse.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
[Updated on: Tue, 28 April 2020 16:16] Report message to a moderator |
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| Re: Here's one for the savvy.... [message #354226 is a reply to message #354217] |
Tue, 28 April 2020 16:20 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Rich,
the tank job is really not that terrible of a project, and really is nice once it is done. You know what you have after that.
the biggest thing is to get it at the right height, and jack it up. The other thing is getting the fuel out. I found using an electric pump drains 99% of the fuel out, if you just hook it up and suck the fuel out of the pickups. it takes at least 15 gallons of gas to pour back in, before it will start priming and sucking gas again. last couple tanks we emptied that way, there was hardly any gas in the tank to slosh out and dump on you when you go to pull the tanks down.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: Here's one for the savvy.... [message #354227 is a reply to message #354217] |
Tue, 28 April 2020 17:48 |
Rick Staples
Messages: 126
Registered: May 2014
Location: Johnstown, Colorado, USA
Karma: -1
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Rich,
Being a bit of a fumble-finger myself, I'd make darn sure I had new sending unit O-rings on hand when dropping the tanks. I screwed mine up the first time around and had exactly your symptoms. That said, as everyone pointed out, there are lots of potential leak points in there, including the sending unit electrical terminal itself.
While in there the last time, I noticed that one of my pickup tubes sat about 2 inches off the bottom of the tank. (No way it should take 15 gallons to start picking up fuel, IMHO.) So I carefully bent it down a bit.
BTW, if you can get the drain plugs loose, coat them with anti-sieze or some such to make sure they come out next time.
HTH
Rick Staples
Rick Staples, '75 Eleganza, Johnstown, CO
"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien
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| Re: [GMCnet] Here's one for the savvy.... [message #354228 is a reply to message #354227] |
Tue, 28 April 2020 17:52 |
Bruce Hart
Messages: 1500
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
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Senior Member |
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Replace the plugs with the external square head instead of the internal hex.
On Tue, Apr 28, 2020 at 4:49 PM Richard H Staples via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Rich,
> Being a bit of a fumble-finger myself, I'd make darn sure I had new
> sending unit O-rings on hand when dropping the tanks. I screwed mine up
> the first
> time around and had exactly your symptoms. That said, as everyone pointed
> out, there are lots of potential leak points in there, including the
> sending unit electrical terminal itself.
>
> While in there the last time, I noticed that one of my pickup tubes sat
> about 2 inches off the bottom of the tank. (No way it should take 15
> gallons
> to start picking up fuel, IMHO.) So I carefully bent it down a bit.
>
> BTW, if you can get the drain plugs loose, coat them with anti-sieze or
> some such to make sure they come out next time.
>
> HTH
> Rick Staples
> --
> Rick Staples, '75 Eleganza, Johnstown, CO
>
> "Advice is a dangerous gift, even from the Wise to the Wise, and all paths
> may run ill." -Tolkien
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: Here's one for the savvy.... [message #354229 is a reply to message #354217] |
Tue, 28 April 2020 18:28 |
6cuda6
Messages: 975
Registered: June 2019
Karma: -6
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Thanks for the info guys.....i did get 2 sending unit lock rings and seals the last time is was out to visit JimK country. I have replaced many a GM fuel sending unit and yes that tool is awesome but careful use of a hammer and blunt screwdriver can get it done.
Here's hoping its simple.....lol. Now to make a list parts for this job as this virus stuff is cramping my ability to just simple get what i need easily.
Rich Mondor,
Brockville, ON
77 Hughes 2600
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| Re: [GMCnet] Here's one for the savvy.... [message #354233 is a reply to message #354231] |
Tue, 28 April 2020 21:06 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Most of my adult life, I have had a struggle with myself over starting a
procedure that I was unfamiliar with. Procrastination is the name of the
game. Not every time, but mostly my fears have been unfounded. Once I got
involved with the actual work, it usually went off well without all my
reservations coming up and biting me in the butt. Just Do It! is my new
mantra.
Jim Hupy
Salem, Oregon
On Tue, Apr 28, 2020, 6:46 PM 6cuda6--- via Gmclist
wrote:
> Thanks Bruce...guess ill have to drop the tanks and deal with what is
> there....lol.
> --
> Rich Mondor,
>
> Brockville, ON
>
> 77 Hughes 2600
>
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| Re: [GMCnet] Here's one for the savvy.... [message #354234 is a reply to message #354230] |
Tue, 28 April 2020 21:13 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Also pay particular attention to the electrical connection for the fuel
level sender -- the insulating feed-thru can deteriorate and create a
leak. I don't have a good fix for that -- I tried replacing the insulator
with a nylon one, which only lasted a year or two. I finally modified some
SS assemblies from eBay -- but didn't get very good level accuracy from
those.
Ken H.
On Tue, Apr 28, 2020 at 9:30 PM Bruce Hislop via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Rich,
> Here are some pic from when I last had my tanks down. Mine was leaking
> from the vapour port as was previously mentioned. The nipple seams to be
> installed using a crimp method like a pop rivet and becomes loose and
> leaks. I replaced mine and sealed it with JB weld. About 5 years now and
> still
> good.
>
> http://www.gmcmhphotos.com/photos/g7006-fuel-tank-lines.html
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Here's one for the savvy.... [message #354250 is a reply to message #354217] |
Wed, 29 April 2020 12:00 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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I trade on Matt and Ken's experience. Take the dam' things down once, and do ALL of it. ew seals, good electrical connections, proper barrier hoses, use the genset feed if it was a trandmode with a tee, etc. If I had to take rust off the exterior, a couple rattle cans of Zinc - it.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: Here's one for the savvy.... [message #354254 is a reply to message #354250] |
Wed, 29 April 2020 14:16 |
6cuda6
Messages: 975
Registered: June 2019
Karma: -6
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Agreed Johnny...hence all the questions as they are only going out once if i can help it.
Johnny Bridges wrote on Wed, 29 April 2020 13:00I trade on Matt and Ken's experience. Take the dam' things down once, and do ALL of it. ew seals, good electrical connections, proper barrier hoses, use the genset feed if it was a trandmode with a tee, etc. If I had to take rust off the exterior, a couple rattle cans of Zinc - it.
--johnny
Rich Mondor,
Brockville, ON
77 Hughes 2600
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| Re: Here's one for the savvy.... [message #354273 is a reply to message #354255] |
Wed, 29 April 2020 22:43 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
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Check the hose barb for the vent on the tanks carefully. The one on my rear tank was loose in the tank due to rubbing on the floor. I could not believe their was no top retention for these tanks except the floor! So I sealed the loose crimp connection with superglue, and then reinforced it with JB weld type stuff, and then glued pads on top of the tanks to stop the fittings (hose barbs) from abrading against the floor. Could not come up with quick and easy way to retain the tanks from the top down so I just improved GM's idea a little with the plastic pads from some CD-ROM packing. No evidence of there ever being any pads up there.
After fixing that and replacing the distorted and broken Corvette vapor separator valve in the wheelwell, no more leaks!
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: Here's one for the savvy.... [message #354274 is a reply to message #354273] |
Thu, 30 April 2020 07:00 |
6cuda6
Messages: 975
Registered: June 2019
Karma: -6
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Senior Member |
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Thanks for the tip Terry! Ill get a look at that for sure.
Bullitthead wrote on Wed, 29 April 2020 23:43Check the hose barb for the vent on the tanks carefully. The one on my rear tank was loose in the tank due to rubbing on the floor. I could not believe their was no top retention for these tanks except the floor! So I sealed the loose crimp connection with superglue, and then reinforced it with JB weld type stuff, and then glued pads on top of the tanks to stop the fittings (hose barbs) from abrading against the floor. Could not come up with quick and easy way to retain the tanks from the top down so I just improved GM's idea a little with the plastic pads from some CD-ROM packing. No evidence of there ever being any pads up there.
After fixing that and replacing the distorted and broken Corvette vapor separator valve in the wheelwell, no more leaks!
Rich Mondor,
Brockville, ON
77 Hughes 2600
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| Re: Here's one for the savvy.... [message #354275 is a reply to message #354274] |
Thu, 30 April 2020 07:13 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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if you are having clearance issues to the floor, I would suspect your body pads are not in good shape. the tanks bolt to the frame, and there should be some space between the tank and the floor. tank should float with the frame and not be attached to the floor. Opposite on a black sewer tank, that rides with the body and is bolted to the floor, not the frame.
but Like I said, those vent nipples would be the first place I would look for a leak, both the hose, or the nipple into the tank.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: Here's one for the savvy.... [message #354335 is a reply to message #354217] |
Fri, 01 May 2020 12:19 |
6cuda6
Messages: 975
Registered: June 2019
Karma: -6
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Senior Member |
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If i went with solid supply lines on the tank and solid vent lines on the tank.....does anyone remember how lone they needed for the remainder of the rubber line?
I'm just trying to buy the correct length of lines...Gates Barracade is not cheap so if i don't need 25ft and only 15ft that's a hug difference $$$ wise.
Rich Mondor,
Brockville, ON
77 Hughes 2600
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| Re: Here's one for the savvy.... [message #354338 is a reply to message #354335] |
Fri, 01 May 2020 14:15 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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I know everything in canada is more expensive it seems. - but I would think anything is comparable.
I did not think it was too expensive, you want the carburation hose: GAtes #27315 for the 3/8" and gates #27314 for the 5/16
now if you are going with EFI, then that is a different story. the EFI hose is expensive. for my EFI, I have the pumps just forward of the tanks, so I am using the low pressure hose from the tanks to the pumps, then I switched to hardline to the engine bay, where i switched back to expensive EFI hose.
the proper brass comression fittings to work and deal with the hardline, and the cost of the hardline itself, I would think would be more money then the low pressure fuel hose.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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