Fuel Line replacement

[choctawmel]

Thought today would be a great day to start replacing the rubber fuel hoses back my the gas tank.

This hose is in the worst shape and my target for today. It connects the fuel regulator to the steel line behind the gray water tank and goes to the engine. Which means the gray water tank must come down.

I ripped into the closet behind the shower thinking I could get to where the drain/vent goes into the tank. Not an ezey feat with it glued and stapled! NOPE! not the way.
I pulled a pan out from under the shower to find a p-trap and pipe going over the frame to the waste tank.
Looking at the gray water tank, looks like the air tank for the air ride will have to come off and maybe the tax axle as will. The only problem is, HOW DO YOU GET THE 'IN' PIPE LOSS ON TOP OF THE GRAY WATER TANK!
I back up, changed course, put the closet back together, drilled the lock out of the safe, pulled the broke blade off the bathroom vent.
Got to think a little more before I go back to the tank removal business. Hope someone knows the simple way to go there.

[Keyair]

I feel your pain..
My gas lines are up for replacement too.. as are Derek's!
Thats crazy that a critcal joint is behind a water tank!
As I explained to Derek, the rubber used in the older vehicles is not alcohol resistant... unlike me...
I know this because I asked a friend of mine to store my 1974 Alfa Spider in his underground garage while I was out of the country awaiting the INS to approve my Visa...
Was told 6 weeks...
I was out 9 months.
My friend called me because, with good reason, he was freaked out by fuel smell and dripping...
I had the car hauled and repaired.. and it cost me $1200.
That cured it while it was sitting... but it didnt cure it all.
I ended up replacing every single line, and O ring in the whole system, including the fuel return lines before I cured the smell and dripping.

[crazeevw]

Hi Mel,
Glad to see this thread started. Haven't gotten underneath my moho yet, but it's better to go ahead and get this done before more damage occurs. Something I thinking, while I'm replacing fuel line, I'm going to replace the electric fuel pump and any filters between the fuel tank and the engine. Keep up posted with your progress and pix. Hoping to start mine tomorrow!
Thanks, Derek

[DaveFL]

Did you see the GM tech bulletin on fuel lines and type they should be, keep rubber to minimum and make sure none get crushed or kinked. Seems like they had a problem years ago and had to have the MH manufacturers review what they were doing. Don't decrease any diameters, keep plastic ties for other equipment to a minimum.

[Keyair]

Good info.
Anyone have an opinion or experience with fuel line that will last longer?
I was kinda eyeing the SS Braided line for underhood, but if I can get a good deal on a bulk purchase, I would like to go that way for it all...

I found this comment and spec aboout "Weatherhead" fuel line that people are using in Marine engine applications..

Excellent resistance to heat, ozone, and permeation by
alcohol blended gasoline and diesel fuels. Compounded
to meet or exceed SAE J1527 Type B, USCG - Type B, USCG
and NMMA standards for fuel feed and vent hoses.

[ScrapIrony-2]

You might consider re-routing your fuel line...mine runs from the tank on the street side, along the chassis, runs through the first fuel filter, moves over to the curbside along the cross member at the rear tag...the fuel pump and bypass are bolted to the cross member...
I have had my gray water tank removed and 'welded'...fairly extensive work...the closet floor was ripped up, and the commode platform was pulled loose(talk about riding a bucking bronco...!). mike

[crazeevw]

Hey Steve, in all of your pdf files, is there anything showing how Airstream may have routed the fuel lines? As far as going with the Weatherhead fuel line, I'm guessing that car manufacturers are using some type of fuel line now that has to be resistant to alcohol blended fuels, especially those vehicles that are E85 compliant. Off to see what kind of fuel line the E85 vehicles use. If I find something, I'll be sure to post here on this thread.
Mel, did you have any particular fuel line you were planning on using?
Thanks, Derek

[Keyair]

I have not narrowed down my Fuel line spec yet.

Mel's post and this whole "Fuel Line behind the grey tank issue" has me thinking and looking at the whole ordeal.

Some food for thought and info on what I can see in my 1984 345...
Please chime in if I miss something!

From front to back, here is my plan:

The flex line from the Carb to the hard pipe on the top of the engine...
Someone put a PLASTIC filter inline on top of a HOT Engine...
Not smart, and heats fuel up too!



My plan is to remove that, replace that line with SS Braided, feeding a chassis rail mounted Adjustable Fuel Pressure Regulator, with Fuel Pressure Guage, then the Fuel flow Sensor for my Zemco Trip Computer, then a SS braided to the carb.
The Quadrajet has a paper filter inside the fuel inlet, so dont forget that one.

Replace both rubber lines on the engine Mech fuel pump with SS Braided.

Replace flexible pipes and filter on kerbside chassis rail.. Its forward of the entrance Door, and near to the RH exhaust and Battery Tray, so I am leaning toward SS Braided there too.
Mine says Wix 33482.




Moving rearward, approximatly behind the entrance door step, there are 2 rubber sections in the lines on the chassis rail here... and BOTH of mine are showing signs of weepage.



I see what looks like 3 fuel related lines on the chassis rail... so fuel feed, fuel return and vapor?

Looking rearward, over the rear axle I see another 2 Joints and rubber lines passing thru a hole in the chassis rail and into the area where the Grey tank is... Top LH side of this pic..


Then Rearward of the axles and grey tank a rubber pipe emerges, and joins to my Aux fuel pump and rear filter... and up onto the top of the gas tank...



My fuel pump mounting is falling apart AND poorly mounted/planned.
Hangs right in the path of destruction from road hazard kicked up by rear tires!

I am gonna move the pump up and mount it on rubber mounts on the upper L of the Chassis rail, secure and mount the filter, and lines where they are NOT hanging free and swinging/chaffing the pipes!

Looks like the gas tank has to be dropped to get at the lines to and from it...
I guess thats a good time to inspect, clean and seal the interior and exterior before it rusts thru...
FUEL TANK REPAIR KIT-POR-15 Inc.

Mel, is the pipe over the Grey tank all flex line?
If so, maybe you could attach a new line the the old one and pull it thru?
Or maybe re-route the pipe around or under... lets face it even that would be better/safer than not being able to see and check its condition!

My rear pipe says 5/16"... is that the correct size?

Also, as I told Derek, my filler to tank Pipe was bad... and weeping causing a bad gas smell when filling up.
Replaced mine, and FYI the original was 1 3/4" dia x 24" long, but I had a pice of 2" in my garage so used that for now.


Also inspect the vent pipe that runs along side it...
Pic of mine showing leakage from filer pipe close to neck, LH side...


Lets not forget the Genset feed pipes while we are doing this!

[DaveFL]

Did I count right 4 fuel filters? Find one that is cheapest with the best specs mount it close to fuel pump. Is the plastic one on the motor replacing the paper in carb filter or is it still in there? All if any junk in the fuel should be trapped before the pump, mine has an in tank pump with prefilters before it. What I found is that most junctions have decreased internal diameters, causing poor flow. Unless you oversize you will need 3 maybe 4 different sizes. I saw the specs on my 454 and if you ran it wide open it can really suck up the fuel, so supply line should be the big one, looks like PO took out the original filter and put in a section of rubber about midway, unless it was the original location of the fuel pump booster, early models had a mechanical on the engine and an electrical one close to the tank. They had a tremendous problem with vapor lock, and sent out service bulletins to MH makers saying they caused it by their modifications.

[Keyair]

Yes Dave, you would be correct.... 4 on the Motor feed!
I have a Aftermarket Edelbrock Carb, but I assume it also has a filter inside.

The one on the top of the engine is NOT stock, and COME ON..
If a Mechanic did this I want to smack him..
Umm... lets think about the issues.. aside form adding ANOTHER filter to the 3 already in line...
An unsecured plastic filter sitting on top of a hot engine where it will soak up heat, rattle about, heat fatigue, crack, leak, and boom, there goes an engine fire!

Oh, and dont forget the 2 filters on the genset... the one inside the Facet Fuel pump, and the one someone added...

I am aware of the vapor lock issue, and you can read all about it in the 1987 Chassis manual available on Airstreams Website.
My rear mounted Aux pump is typical of the mod that was done, and I have a switch to power it under the dash. I need to replace the rubber that it is mounted on, so might as well do the job properly, and get it and that rear filter up and out of the debris impact zone!

[crazeevw]

gotta get into this on my day off this week. Guess with all of the suggestions and hints contained here, I've got plenty to look for. Did see that the electrical pump at back is attached to some kind of 'flaring' behind the gray water tank. Set-up is completely different from yours KeyAir. I'll get pix posted soon.
Thanks, Derek

[choctawmel]

I don't know how you can change the filter by the tank without one of these

The first time I pulled the hose off the filter to change it, I got a major shower of gas before I come it the hose back on the filter. BTW that's the hose I use for gas. It's high pressure, 1225 PSI fuel line hose.

This is my injector pump(add on EFI). Filter in, filter out. Outside frame behind the batteries. Need a filter to protect the pump and the EFI body.
The P-30 fuel line is 1/2 and runs on the outside of the frame. Right at the front spring hanger it does a 90 and goes to the inside with another 90 and goes on back with the return and vent lines. Then at the front of the gray water tank it goes to rubber

I would bet that this is where the gas tank was before the frame was extended. (That white wire goes to the air pump, not good.)
Now the whole job looks doable! Fish new rubber (not really rubber, just old habits are hard to break) over the top of the gray water tank and go.
I need to run a new return tube too. The EFI return needs to be at least 3/8".
The plan is to try and almost run out of gas before I began.
Thanks for the picture Keyair. Made me crawl around under the greasey belly a couple more times.

[Keyair]

Originally Posted by choctawmel

Thanks for the picture Keyair. Made me crawl around under the greasey belly a couple more times.

Well, just returning the favor!

[crazeevw]

Mel,
So instead of filling up my tank, I guess I need to take a road trip to deplete it as much as possible. Mmmm, just when gasoline here in Florida was below $3.50 a gallon too. Maybe just drain it into whatever gas cans I can, or just go and enjoy some time behind the wheel of my Airstream. Thinking, Mom and Dad have yet to see the 'beast' yet, 140 miles roundtrip, that should get me down a bit, huh?
Thanks, Derek

[DaveFL]

Originally Posted by choctawmel

Filter in, filter out. Outside frame behind the batteries. Need a filter to protect the pump and the EFI body. .

I understand the filter before the pump, but why after, is the pump adding something to the fuel before it sends it to the motor? Filter like Keyairs at the motor makes more sense, sort of. But his carb has one the mechanic couldn't find, at least yours would be metal body.

[crazeevw]

Should weather cooperate, I hope to get under moho this Thursday, take lots of pix, while engine is running to see where I'm getting the leaks. Hopefully, I'll be able to determine if this is something I want to do, or farm out. Has anyone determined if the entire fuel line, from tank to engine is entirely rubber fuel line, or at some point, is metal?
Thanks, Derek

[choctawmel]

Originally Posted by crazeevw

Mel,
So instead of filling up my tank, I guess I need to take a road trip to deplete it as much as possible. Mmmm, just when gasoline here in Florida was below $3.50 a gallon too. Maybe just drain it into whatever gas cans I can, or just go and enjoy some time behind the wheel of my Airstream. Thinking, Mom and Dad have yet to see the 'beast' yet, 140 miles roundtrip, that should get me down a bit, huh?
Thanks, Derek

The trick is to not run out on that trip. My next planned trip is farther then I can get with the around 40 gal left now will take me.
Wonder if I could block the tank, then jack the motor home up enough to get to the lines?

[crazeevw]

Hi Mel, someone had mentioned the excess amount of gas under pressure when they went to work on their fuel line. Sure your moho is the same, when you twist the fuel cap, there is an extreme amount of pressure released. Guessing that if you release all of the pressure, some of excess fuel under pressure would also be alleviated.
As far as 'blocking' the tank, not sure how you plan on doing that. I do know that I need to invest in a good floor jack and jack stands if I'm getting under 14,000lbs of motorhome.
Keep us posted on your progress.
Thanks, Derek

[Keyair]

Derek,
Yours is a later coach, and from what I am reading it should have the later modified 1/2" metel pipe on the OUTSIDE of the chassis rail. This was done to shield the fuel line from exhaust heat, and improve cooling, and thus further preventing heat soak and the resultant vapor lock. You can read all about the Technical Issue in the Chevy Chassis Manual. The majority of the fuel line is metal, with just a few section of flexible line at engine, filters, and Gas tank.

Mel, You could use the fuel pump to empty it, or actually, mine has a drain plug in the bottom front of tank.
I have been using my Motorcyle lift.. its stable, and works great for this type of thing. HF has a reasonable one on sale for $99. Failing that, I would put blocks under each end, and lower it one enda at a time with a jack.

I have decided that I am going to seal the inside of mine with POR15 Tank sealer while its out/down. I do have a Borascope Inspection Camera, so I want to see how it is inside. Makes sense to me to do this now.
Sent them an Email, and got a reply yesterday saying 3 quarts should be plenty, and so thats about $60 in sealer, plus whatever prep solvents I will need. I would rather do it all together, that way I will not worry about further rusting or sediment, and all I should need to do is change the filters for the foreseeable future.

[ScrapIrony-2]

FWIW: I ran around Tucson to several automotive stores looking for the small filter that attaches ouside the carb...found them at NAPA.

NAPA Gold #3052
mike