Fuel tank leak - fuel pump cover or pressure release valve?

Hi
When filling up my ´94 Gr. Cherokee the other day I discovered it was
leaking fuel. The leak seems to originate from either the fuel pump
mounting or the pressure release velve on the the top of the tank. (So
when those first few liters in the top of the tank had drained away,
it stopped..) I've understood that the gasket on the fuel punmp cover
can start to leak which means i'll have to change it. What i'm
woondering is if anyone has any experience with the pressure release
valve leaking? We'we had very cold weather (- 20 C) for several days
preceding me discovering the leak. Might this have anything to do with
it?

Regards - Snowman

Did you see the leak or are you guessing?

I have heard of more filler hose leaks than pump gasket leaks. The
filler hose has a clamp on the tank that gets a bit loose. I don't know
where your pump is, but on our Cherokee we would have to get down to 3/4
or lower to stop it's gasket from leaking and the pressure vent is dead
top center so only the fuel that goes up the filler pipe can leak out of
it, once the filler has emptied no more top leak.

I have never heard of the pressure relief valve leaking, but....

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

zarro wrote:
>
> Hi
> When filling up my ´94 Gr. Cherokee the other day I discovered it was
> leaking fuel. The leak seems to originate from either the fuel pump
> mounting or the pressure release velve on the the top of the tank. (So
> when those first few liters in the top of the tank had drained away,
> it stopped..) I've understood that the gasket on the fuel punmp cover
> can start to leak which means i'll have to change it. What i'm
> woondering is if anyone has any experience with the pressure release
> valve leaking? We'we had very cold weather (- 20 C) for several days
> preceding me discovering the leak. Might this have anything to do with
> it?
>
> Regards - Snowman

Hi. thanks for the reply

I crawled under the car and the leak definitly comes form either the
fuel pump cover or the valve. The pump is mounted in a indentaion in
the top of the tank and the gas funnels out from that., If the filler
hose was leaking the fuel would pour down from it, down the side that
wouldn't it? "My leak" pours down the front of the tank just behind
the differential. Also the leak stopped very quickly - my guess is
that it was only the fuel in the filler hose the driained awy. Efter
the leak had stopped the fuel gauge stull read full. My mechaniv
suggested that due to my habit of not filling the tank all the way up
the gasket on the fuel pump cover might have dried up and cracked. Is
that likely?

Regards Snowman



Mike Romain > wrote in message >...
> Did you see the leak or are you guessing?
>
> I have heard of more filler hose leaks than pump gasket leaks. The
> filler hose has a clamp on the tank that gets a bit loose. I don't know
> where your pump is, but on our Cherokee we would have to get down to 3/4
> or lower to stop it's gasket from leaking and the pressure vent is dead
> top center so only the fuel that goes up the filler pipe can leak out of
> it, once the filler has emptied no more top leak.
>
> I have never heard of the pressure relief valve leaking, but....
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> zarro wrote:
> >
> > Hi
> > When filling up my ´94 Gr. Cherokee the other day I discovered it was
> > leaking fuel. The leak seems to originate from either the fuel pump
> > mounting or the pressure release velve on the the top of the tank. (So
> > when those first few liters in the top of the tank had drained away,
> > it stopped..) I've understood that the gasket on the fuel punmp cover
> > can start to leak which means i'll have to change it. What i'm
> > woondering is if anyone has any experience with the pressure release
> > valve leaking? We'we had very cold weather (- 20 C) for several days
> > preceding me discovering the leak. Might this have anything to do with
> > it?
> >
> > Regards - Snowman

zarro did pass the time by typing:
> Hi. thanks for the reply
>
> I crawled under the car and the leak definitly comes form either the
> fuel pump cover or the valve. The pump is mounted in a indentaion in
> the top of the tank and the gas funnels out from that., If the filler
> hose was leaking the fuel would pour down from it, down the side that
> wouldn't it? "My leak" pours down the front of the tank just behind
> the differential. Also the leak stopped very quickly - my guess is
> that it was only the fuel in the filler hose the driained awy. Efter
> the leak had stopped the fuel gauge stull read full. My mechaniv
> suggested that due to my habit of not filling the tank all the way up
> the gasket on the fuel pump cover might have dried up and cracked. Is
> that likely?

The gasket will not dry out and crack, it's just a real big o ring.
It can get damaged or not seat properly if your not careful when putting
the pump back in.

In the book, you mark where the large nut is then count the number of
turns to remove it. When putting it back on, you count the same number
of turns till the marks line up, then tighten it one more inch.

Your leak could be the quick connects. A pinched O-ring in those will
cause leaks. To my knowledge there is only one rebuild kit for the
smaller hose. Mopar part number 1-83502745. But the little o-rings
are fairly common.

--
DougW

LOL! No.

The gaskets are synthetic rubber and our 88's was still fine to use with
a new tank.

It sounds like you are going to have to drop the tank for a look.

Mike


zarro wrote:
>
> Hi. thanks for the reply
>
> I crawled under the car and the leak definitly comes form either the
> fuel pump cover or the valve. The pump is mounted in a indentaion in
> the top of the tank and the gas funnels out from that., If the filler
> hose was leaking the fuel would pour down from it, down the side that
> wouldn't it? "My leak" pours down the front of the tank just behind
> the differential. Also the leak stopped very quickly - my guess is
> that it was only the fuel in the filler hose the driained awy. Efter
> the leak had stopped the fuel gauge stull read full. My mechaniv
> suggested that due to my habit of not filling the tank all the way up
> the gasket on the fuel pump cover might have dried up and cracked. Is
> that likely?
>
> Regards Snowman
>
> Mike Romain > wrote in message >...
> > Did you see the leak or are you guessing?
> >
> > I have heard of more filler hose leaks than pump gasket leaks. The
> > filler hose has a clamp on the tank that gets a bit loose. I don't know
> > where your pump is, but on our Cherokee we would have to get down to 3/4
> > or lower to stop it's gasket from leaking and the pressure vent is dead
> > top center so only the fuel that goes up the filler pipe can leak out of
> > it, once the filler has emptied no more top leak.
> >
> > I have never heard of the pressure relief valve leaking, but....
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > zarro wrote:
> > >
> > > Hi
> > > When filling up my ´94 Gr. Cherokee the other day I discovered it was
> > > leaking fuel. The leak seems to originate from either the fuel pump
> > > mounting or the pressure release velve on the the top of the tank. (So
> > > when those first few liters in the top of the tank had drained away,
> > > it stopped..) I've understood that the gasket on the fuel punmp cover
> > > can start to leak which means i'll have to change it. What i'm
> > > woondering is if anyone has any experience with the pressure release
> > > valve leaking? We'we had very cold weather (- 20 C) for several days
> > > preceding me discovering the leak. Might this have anything to do with
> > > it?
> > >
> > > Regards - Snowman

As Doug, and Mike already have said it is very rare for that O ring
to leak once seated, it under no twisting action that may wear them out,
like their use at the Air Conditioning, power steering, and automatic
transmission connection. http://www.billhughes.com/01XJfuelPump.pdf
God Bless America, ßill O|||||||O


zarro wrote:
>
> Hi. thanks for the reply
>
> I crawled under the car and the leak definitly comes form either the
> fuel pump cover or the valve. The pump is mounted in a indentaion in
> the top of the tank and the gas funnels out from that., If the filler
> hose was leaking the fuel would pour down from it, down the side that
> wouldn't it? "My leak" pours down the front of the tank just behind
> the differential. Also the leak stopped very quickly - my guess is
> that it was only the fuel in the filler hose the driained awy. Efter
> the leak had stopped the fuel gauge stull read full. My mechaniv
> suggested that due to my habit of not filling the tank all the way up
> the gasket on the fuel pump cover might have dried up and cracked. Is
> that likely?
>
> Regards Snowman
>
> Mike Romain > wrote in message >...
> > Did you see the leak or are you guessing?
> >
> > I have heard of more filler hose leaks than pump gasket leaks. The
> > filler hose has a clamp on the tank that gets a bit loose. I don't know
> > where your pump is, but on our Cherokee we would have to get down to 3/4
> > or lower to stop it's gasket from leaking and the pressure vent is dead
> > top center so only the fuel that goes up the filler pipe can leak out of
> > it, once the filler has emptied no more top leak.
> >
> > I have never heard of the pressure relief valve leaking, but....
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > zarro wrote:
> > >
> > > Hi
> > > When filling up my ´94 Gr. Cherokee the other day I discovered it was
> > > leaking fuel. The leak seems to originate from either the fuel pump
> > > mounting or the pressure release velve on the the top of the tank. (So
> > > when those first few liters in the top of the tank had drained away,
> > > it stopped..) I've understood that the gasket on the fuel punmp cover
> > > can start to leak which means i'll have to change it. What i'm
> > > woondering is if anyone has any experience with the pressure release
> > > valve leaking? We'we had very cold weather (- 20 C) for several days
> > > preceding me discovering the leak. Might this have anything to do with
> > > it?
> > >
> > > Regards - Snowman