Trying to find fuel leak

[dickcarl]

I have a 1988 Itasca Sunflyer, recently purchased.  I'm trying to fix a fuel leak without pulling the tank.  I've made the "hole in the floor" and revealed the top of the tank where the fuel pump goes in.  None of the hoses are leaking.  I'm thinking it must be the regulator or some other connection, as the fuel drips down from the top of the tank.

Does anyone know which of the three lines coming from the top of the tank (i.e. fuel pump, return, and breather) are which?  I'd like to disconnect the fuel line and run it direct to the filter in the frame rail with an after-market regulator.

Other thoughts are also welcome -- just sitting here with rust in my eyes trying to come up with good ideas.

[Rickf1985]

There is already an aftermarket regulator mounted on the passenger side frame rail somewhere near the tank. They are famous for leaking. Mine looked like a leak at the front side of the tank but turned out that the regulator was spraying gas back against the tank. My Winnebago Chieftain was a BEAR to get to the regulator! I just picked up a Pace Arrow and the regulator is right out in the open on the outside of the frame rail. I would suggest following the line back from the front until you hit the regulator.
Here is a thread I had for my regulator repair.
http://www.classicwinnebagos.com/forum/index.php/topic,9000.msg59657.html#msg59657

[dickcarl]

Yes, I can see what I think is the regulator nestled snugly inside the fuel rail behind some exhaust parts and the brake drum.  Probably can't get to it without removing the duals, the exhaust, and most of the rig.  That's why I'm thinking of a bypass.  And it's far below the top of the tank, so I don't think it's what's leaking.

Any idea which of the three outputs might be the pump?

[gpw9552]

As far as which one is the output from the tank, it will be the largest line.

[Rickf1985]

You will also have a return line so if it looks like it might not be under pressure it could be that. More likely the pressure line though.

[HandyDan]

Maybe this will help:

[dickcarl]

This is exactly what I needed.  I'm ready to dive in.  See you on the other side.

[ClydesdaleKevin]

Mine only has 2 lines coming off the top of the gas tank...lol!  My genny runs off a t-fitting on the return line (with its own set of problems because of that).

Kev

[cook elandan]

When i had to fix the leak in the regulator.  Mine was located behind the tag wheel. I was able to remove the wheel and all that I did was remove the 4 top screws, popped off the top and cleaned it up and replaced the spring and installed new gasket.  As long as you dont mess with the adjusting nut just remove, clean and replace parts.  My regulator is mounted on the inside of the frame rail but the top stick through a notch in the frame rail. that allows you to adjust the regulator if it is needed.

[dickcarl]

So, I assume that means you can run your tank dry with the generator?

[ClydesdaleKevin]

Nope, because the return line doesn't go all the way to the bottom.  But what was happening if I ran the genny too long, was that for some reason the fuel would lose vacuum even with all new fuel hoses, and the genny would stall from not getting any fuel, unless I started the motorhome engine, which would keep it running.  I installed a shutoff valve forward of the T fitting...so if I close off the fuel return line going to the engine, the genny runs fine all day long.  This is my temporary solution, since it requires crawling under the motorhome to close and open that valve.  Eventually I will install an electric fuel shutoff solenoid type thingy, so I can just do it remotely with the flip of a switch.

Kev

[Rickf1985]

Or tap into your main fuel line and watch to make sure you don't run yourself out of gas. It is not like it will happen overnight. You might have to add a second regulator to drop the pressure down more than the 3-5 lbs. from the original regulator when the engine is running. OR........................... Just get the right sending unit with the genny line on it.

[ClydesdaleKevin]

That might be an option, Rick...since my tank doesn't have a separate pickup for the genny.  Another awesome part of the design on my 89 HR Imperial is that I can access the top of the fuel tank without dropping the tank...by sitting inside the wheel well behind the rear tag axle.  I can actually reach in there, with about a foot of clearance over the tank.  I know...been there done that...changed the electric fuel pump out 3 times before realizing it was the no longer available relay.  So I rewired it completely to a 30 amp standard relay.  Haven't had a fuel delivery problem since.

Kev

[dickcarl]

UPDATE:  I completely replaced the line for the fuel pump, from the tank all the way to the filter on the frame rail.  Good news is that it works great.  Bad news?  Still have a (smaller) leak back at the tank, somewhere, near the top.  Next up is replacing the return line in the same area.  But my new skills mean it should take much less time.  And when this is done, pretty much everything that could leak is repaired and good for years.

The real pain of this stuff is that it takes you hours and hours to become skilled at it, and then you never need to do it again. It might be time to open an RV repair shop.

[CJ7365]

Could it be leaking from the sending unit gasket? 

specifically looking at Item #17 in your picture you posted in your original post

it could leak even know your not starting or driving it based on pressure in the tank from the temp rise throughout the day, just a guess

[Rickf1985]

If it were doing that it would mean the tank was overfull and it would be leaking all the time, not just when it is running.

[dickcarl]

SUCCESS!  I have now replaced both the fuel pump line and the return line from the tank to very far forward on the chassis -- just about where the propane tank is -- with fresh hose.  Fired her up and ran for ten minutes without so much as a drop leaking. More testing to come.

I am now available for consulting on gas line replacement on old motorhomes.  With this chassis.  In warm places, with nice flat places to work.

Thanks again for all the help, suggestions, photos and encouragement.  Sometimes even a blind squirrel finds an acorn.

[ClydesdaleKevin]

SWEET!!!

Kev

[M & J]