fuel leak at carb filterhousing

P

paul zerkel

New member
Sep 6, 2007
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I have a fuel leak at the carb. It appears to me to be coming from where the filter housing attaches to the carb body, and not from the fuel line from
the fuel pump. FWIW, I am using this fuel line from Applied. http://www.appliedgmc.com/prod.itml/icOid/853

I had a spare parts quadrajet, and robbed the filter housing from there. That did not fix the leak.

I am not sure how to fix this. But obviously it needs to get fixed as I am not driving the coach with gas dripping onto the motor. I am really not
ready to put fuel injection on at this point, but is it going to take a card rebuild? I am willing to go that far if needed. But I wanted to find out
if there may be a simpler/cheaper solution first.
--
Paul Zerkel
'78 Eleganza II
Salisbury IL (near Springfield)
 
Unfortunately it is very easy to cross thread the filter housing and wreck the threads in the carb body (float bowl). I suggest to anyone who will
listen to turn the filter housing three or four turns before putting a wrench on it. It's best to install the filter housing completely by hand and
just snug it up with a wrench then screw in the fuel line. If you are lucky the gasket is crooked or the filter housing is just not seated
completely. If you are unlucky the threads are stripped. You may be able to clean them with a tap, but most likely you will have to use the float
bowl from your spare quadrajet. Inspect the threads very carefully before proceeding.
--
Chris Geils - Twin Cities
1978 26' Kingsley w/ very few mods; Headers, Progressive Dynamics 9040, aux trans cooler, one repaint in stock colors, R134a, Al rad, 50k mi
 
Remove fuel line. Remove fuel inlet. Inspect threads and gasket condition. When reassembling snug inlet to carb body. When installing fuel line use
opposing wrenches to not move inlet. Avoid winding up the fuel line which will then apply reversing torque on the inlet and may loosen it during
heat/cool cycles.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
There is supposed to be a gasket between the filter housing and carb body.
It sometimes fails and leaks. It is really thin and fragile, as well as
hard to see. If the threads are stripped, there is a TOMCO repair kit for
that.
Jim Hupy

On Sat, Jun 2, 2018, 6:12 PM Chris Geils via Gmclist <

> Unfortunately it is very easy to cross thread the filter housing and wreck
> the threads in the carb body (float bowl). I suggest to anyone who will
> listen to turn the filter housing three or four turns before putting a
> wrench on it. It's best to install the filter housing completely by hand
> and
> just snug it up with a wrench then screw in the fuel line. If you are
> lucky the gasket is crooked or the filter housing is just not seated
> completely. If you are unlucky the threads are stripped. You may be able
> to clean them with a tap, but most likely you will have to use the float
> bowl from your spare quadrajet. Inspect the threads very carefully before
> proceeding.
> --
> Chris Geils - Twin Cities
> 1978 26' Kingsley w/ very few mods; Headers, Progressive Dynamics 9040,
> aux trans cooler, one repaint in stock colors, R134a, Al rad, 50k mi
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Paul,

I used the same insulated flex line as you are using, and could not get it to stop leaking. I ordered that hose to replace a PO installed part
regular line and part rubber hose. I thought maybe I was routing it wrong from the fuel pump to the carb, nope it didn't matter which way it went,
still leaked at the inlet. Tried new filter inlet, nope. Chuck Boyd gave me an OEM fuel line and no more leaks. I insulated the line with an
insulating sleeve and gave the flex line to Chuck.

Jerry
--
Jerry Sitzlar..... 77 Eleganza II, Twin bed, dry bath......
Lenoir City, TN
 
You can get the aforementioned 'gasket' at NAPA. They cone in a Dorman 'Help' blister pack. The ones you need ate thin nylon rings. IF that is the
problem, one of those should fix it. I have one of the insulated braided stainless flex lines and have never had a leak problem with it.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member
 
Funny story about this: I had a very slight leak from the filter housing gasket on the way to Las Vegas last January, just enough to make a slight
gas smell, and needed to replace that gasket. On the way to meet my daughter's family for breakfast, we stopped at an O'Reilly's to see if we could
get one. The thirty-something 'assistant manager' had NO IDEA what a Quadrajet even was, much less what kind of gasket I needed. "Is that some kind
of Holley?" he asked.

We looked up the location of the nearest NAPA, and found one a few miles away and barely out of our way back to my daughter's house. There was a guy
there with a gray beard who knew exactly what I needed and exactly where to find it in the store. A few bucks later and we were on our way. I
completed the repair before leaving for our next destination a few days later.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member
 
James H hit the problem. ( If not cross threaded. ) Gasket comes in the carb kit. It's a very thin clear plastic. Look for that gasket on the spare carb fitting. Be very careful not to loss that gasket. Or plan B. Get a vey thin O ring that will fit between the fitting gasket lip on the end. But has the same or smaller OD then the end of the fitting. Install by hand till contact. Then use a wrench for the last turn. Bob Dunahugh
 
You could try using Teflon tape if all else fails.

Mark the edge of the "nut" and start the tape at the mark and put two wraps around the threads. NO MORE than two wraps!

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808
 
Thanks to everyone who responded. I think I have this resolved. I believe I had two issues.

Jim Hupy wrote: "There is supposed to be a gasket between the filter housing and carb body.
It sometimes fails and leaks. It is really thin and fragile, as well as
hard to see."

I did not see that gasket. I bought this kit https://www.napaonline.com/en/p/NDP7309573 And one of those fit. But installing it did not fix the issue.
I took a closer look at my fuel filter. I am not sure what brand that filter was-but I think it was Wix. It did have the integrated gasket on the
inlet end. Pulling the fuel filter I realized there was another separate gasket also in the housing. But looking more closely at the fuel filter, I
realized it was "twisted". It was not true from front to back. I suspect because of this the gasket at the inlet was not seating well enough to seal.

The spare filter I had on hand was an Autozone one. It had neither an integrated gasket on the inlet end nor an included gasket in the package. So I
put the loose gasket that was already in the housing back in, replaced the fuel filter with the spare I had. I ran the engine it was staying dry. I
only ran it for a few minutes. But previously it was leaking even before the engine started, as soon as I started cranking and the fuel pump started
pumping.

A few of you mentioned extreme care is needed to avoid cross threading. I had read this before, and always finger tighten that as much as I can before
putting a wrench to it. But I still worry about tightening it too much. As for the fuel line removal, I always use a flare wrench on the fuel line,
and hold the filter housing with a 1" open end wrench. I guess I should invest in a 1" flare wrench, but have not done so yet.

Also re the fuel line. It seems there are mixed opinions about the Applied flex fuel line I am using. It is a braided steel line with an insulation
sleeve. To me the hose itself looks similar to Applied stainless steel brake lines. Personally I am comfortable with the safety aspect of it. It
certainly makes removal and installation of that carb fuel filter much easier than steel line. And I know it is way safer than the rubber fuel line it
replaced.

Thanks again for everyone's help.
--
Paul Zerkel
'78 Eleganza II
Salisbury IL (near Springfield)
 
I have attached jillions of fuel lines to Rochester carb filter housings (I'm 75) and have never left the gasket out or cross threaded it. On that
stainless flex line it acted like it was too short by just a little. I tried routing it different ways, reversed it, used teflon tape, replaced the
filter housing and gasket and took pictures of another installation to make sure that I was installing it correctly. It just had too much strain on
it and it leaked every time that I tried. Not one single wet spot when I went to the OEM hard line. The PO had installed a new fuel pump prior to my
purchasing the coach, maybe the pump is different than the OEM pump, I didn't compare it. I don't know. I gave the flex line to Chuck B, I don't
know if he ever used it or not. The Applied line is well made and I would have rather used it, but.....

Jerry
--
Jerry Sitzlar..... 77 Eleganza II, Twin bed, dry bath......
Lenoir City, TN
 
Parts House Roulette. We've two here with old gray headed poots working there - Dollar Carburetor and Slack Auto Parts. When you go in, if it's
before about 1996 or so, the youngster calls the Old Poot and asks. And remembers for next time. As a result, there's little turniover in the help
and they learn.

--johnny

--
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" - ol Andy, paraphrased
 
Jerry,
We have a fix for the leaky fitting, calll me.

On Mon, Jun 4, 2018 at 6:03 AM Johnny Bridges via Gmclist <

> Parts House Roulette. We've two here with old gray headed poots working
> there - Dollar Carburetor and Slack Auto Parts. When you go in, if it's
> before about 1996 or so, the youngster calls the Old Poot and asks. And
> remembers for next time. As a result, there's little turniover in the help
> and they learn.
>
> --johnny
>
> --
> 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" - ol Andy, paraphrased
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
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