Diagnosis and Repair of Problems With Your Imperial's Fuel Lines


Imperial Homepage -> Repair -> Fuel -> Lines

Tip from Dick on how to remove fuel lines:

To remove a fuel line (if it is a steel line), you should use a "line wrench" available at your local parts store, it looks like a normal box end wrench but has a slot through it so you can slip it over the line, and is usually a 6 point, rather than the normal 12 point box.  The fuel line may be simply a rubber hose with a normal hose clamp, or if it has never been removed, it may have a "permanent" clamp on it, which you will have to cut with a pair of "diagonal cutters", one of the first tools you should add after you have the basic screwdrivers, wrenches etc.  Don't skimp on tool quality, these will be friends to you for the rest of your life. KD, Craftsman, SK, the NAPA house brand, MATCO, SNAP-ON, and many others are all good brands. For your "dikes" ( common name for diagonal cutters), buy Krauter if you can find them. Don't ever buy any tool not made in the USA or Europe unless you know the reputation of the exact brand (like Makita, Sunnen, and many other oriental companies make very good tools, but the usual counter display type tools made west of San Francisco are nothing but knuckle busters, especially the socket sets.)

You always need to "back up" the non-rotating portion of the connection with a good fitting end wrench, so that the force you are putting on the tubing nut is entirely applied to the screw threads, and none of it applied to the article which it is fastened to (in this case the inserted threaded socket in the tank, if such exists on this car). These fittings are brass, and you don't get a second chance in working with them. The technique for breaking loose a long time undisturbed fitting is to get the two wrenches squarely on their respective hex nuts, and then give a sharp jolt to the one you want to unscrew - the impact is what breaks things loose. I like to get the two wrenches positioned such that they are about 30 degrees out of parallel with each other, then grab them both with one hand, and squeeze the two wrenches together (of course you have to have the handles such that you are turning the threads the right way).

Tip from John:

I just discovered something that I should have checked a long time ago, since I had a '69 Imperial in the early '70's & this same problem happened. There is a rubber splice in the fuel line below the front door that is not that obvious unless your really looking for it. Well, I lost about 2/3 tank of gas on the ground because this hose started leaking & I didn't notice for at least a week. I touched the hose & it crumbled into lots of pieces. By the time I managed to get a piece of hose & a couple of clamps from the garage, I probably lost a couple of more gallons & had gas running down my arms while trying to quickly make the repair.

Back around '73 I looked out the window one morning & saw something was leaking down from the driveway & into the gutter. It turned out to be that same rubber hose. I don't know how many years use this but probably '69-'71 at least. If you've never checked or changed this, you may want to have a look before its an emergency repair.

Addition from Elijah:

John makes a good point -- and I would STRONGLY encourage everyone to check ALL of the rubber pieces of fuel line between the carburetor and the fuel tank, especially if you're not sure if these pieces have ever been replaced.

Depending on the year, there may actually be several pieces of rubber fuel line between the carburetor and the fuel tank. Over the years, these pieces can develop small leaks or even completely crumble. Replacing them is cheap and easy--good insurance, in other words!

As a side note, a few years ago, my '71 Imperial developed a rough idle. After trying lots of other fixes, I happened to notice that the rubber fuel lines at the gas tank (the '71 has the "Vapor Saver" system with about seven pieces of rubber fuel line at the gas tank) were cracked and seeping. It turned out that the fuel pump was actually pulling air INTO the fuel line, cause problems with the idle. Less than $10 worth of fuel hose and about an hour of my time not only fixed the idle, but also made the car MUCH safer.

Tips from Kate:

After my husband had replaced two carburetors, the fuel tank, the float gauge and pickup, two pumps (including bypassing the engine-driven pump with a hi-flow electric unit), several changes of rubber line sections, and generally driving me completely nuts, I undertook to buy about 20 feet of brand new steel line. With a dry afternoon and a bender, I completely solved all problems with power loss, stalling, stumbling etc on this truck. The old hard lines evidently were just porous enough to allow it to draw some air under a heavy pull.

If there is any corrosion at all anyplace on the hard lines, it's a heck of a lot cheaper to replace them with new than to go through all the rest of the systems - starting with new clean fuel pipe can eliminate a lot of other problems before they start, too! For the cars having the fuel lines running through frame sections, this is an especially important item to NOT overlook.

Additions from Dave:

When I replaced the fuel lines on my Imp, I used 5/16 bore copper pipe. The stuff used in central heating. Don't think it will rot for a good while .

Question from Al:

When the car is hot, and I stop and it sits for a few moments, when I am moving down the road again about a half block later it will start choking. If it is not too hot and is on level ground it will start surging and continue with a gradual lessening until it is running fine again. Now when I'm going up hill which I do often when I am driving locally as I live in the mountains, it will happen much more easily and at a cooler temperature. In this uphill situation it will die every time. If I don't stop it will be fine unless it is a very hot day. Then if it is very hot out when I slow down to navigate my neighborhood road it will choke out and die when the grade becomes steep. I then must let it cool down before it will start and stay running again. From what I think I understand about vapor lock this feels like what is happening, that the fuel is boiling in the line and creating air bubbles. But here's the catch. My mechanic put a rubber fuel line and an electric fuel pump on (mounted on the side wall towards the top of the engine compartment.) Shouldn't these things cure a vapor lock problem? The funny thing is, the first year I drove the Hornet which included a hot summer during which I drove the car a lot, it never had this problem, metal fuel line and all.


From Steve:

It sure sounds like a vapor lock problem to me......as long as it is happening only when it is very hot outside. I'd check all of the fuel lines for leakage and insulate the ones inside the engine compartment with something non-flammable which will radiate heat such as aluminum foil. Also, make sure the fuel filter is not too close to the engine. The filter should be made out of metal and not plastic or glass for safety reasons. I like the idea of using an electric fuel pump in your case because fuel is kept out of the hot, engine mounted mechanical pump. If all else fails...there is a product called a "Cool Can" which resembles a large insulated coffee can which has fuel line spiraling inside. You install it under-hood and hook your fuel lines up to it. You fill the can with ice. When the fuel runs thru the spiraled fuel line inside, it is cooled...then the line exiting the Can should be run directly to the carburetor so as not to heat up due to underhood temps. The Cool Can is a pain in the neck....but sometimes it is the only alternative. Racers use the Can a lot. 

From Mike:

I had a familiar problem to yours.  8 mechanics couldn't figure it out and it turned out that I had a piece of rubber hose spliced in with my gas line.  It was kinking and causing it to sputter, stall, and sometimes not start.   I replaced it and my problem is over, the funny part was it wouldn't do it all the time.

From Steve:

When you have the problem try opening the gas cap, if you here pressure, you may have a bad cap, not allowing air in. Loosen cap to see if problem goes away.

From Dick:

This does indeed sound like vapor lock. The usual cause for this is a pinhole leak in the fuel line between the tank and the pump. Since this line is under vacuum during driving, this allows a air to enter the fuel stream, and in hot weather when the fuel gets hot, the air/fuel mixture is very hard or impossible for the fuel pump to move along. The pinhole is too small to allow gas to leak out when the car is parked, but often there is a small stain around it, if you look carefully enough.

Placing an electric pump would have helped if it were placed low, toward the rear of the car (I like to put them on the frame side rails just forward of the rear axle, where they are well protected and gravity fed from the tank). Putting more plumbing under the hood is the wrong way to go, giving more opportunity for the gas to get hot.

I'd say, step one for you is to put the car up on a lift and inspect all the fuel plumbing for any sign of rust or other discoloration of the dust/dirt around it. Then, replace ALL rubber in the fuel system from the tank forward with modern SAE 30R9 or better fuel hose. (Older fuel hose is no good for the modern fuels). After you do that, try just hooking up the rest of the system the way mother Mopar designed it. These cars did not have vapor lock when they were new (imagine someone paying that much for a Luxury car and then discovering it wouldn't go up a hill in hot weather!), so something has deteriorated. Find it and fix it.

The electric pump is a nice feature if you drive the car so seldom that the gas drains back to the tank, it saves wear and tear on the starter, but in your case, you are putting a Band-Aid on cancer.

Question from Dennis (1953):

I need help to get a fuel line part. I need just the male fitting that goes into the gas tank. Mine stripped when it was removed and I cannot get any fitting to go in the female fitting on the tank.

Reply from Roger:

There is a "Chrysler fuel nut" that is still available from any parts house that will look up old car parts. That will replace the male fitting on the end of the fuel line. If you've messed up the female fitting on the tank, that's another problem. Because of the metal fuel line going directly to the tank without a short rubber bit as on later cars, I've found that it's nearly impossible not to strip the nut.

Question from Tim (1956):

Fuel lines seem to be plugged on the '56 that has set for several years. What is the best way to clear them from the tank forward?


From Bill:

Disconnect fuel line at fuel pump & tank.

At the tank end, use a piece of old bed sheet or similar material & form a bag so to speak & tape that to the disconnected fuel line.

Blow with compressed air at the fuel pump end & the home made bag will show you what was plugging the line.

You will also need to clean out the tank but it is very easy to remove & when replacing the tank replace both rubber hoses connecting the filler tube to the tank.

California Rubber has a store in Bakersfield & they have the sizes you need, I got mine there & both fit perfect.

From Dick:

Remember that the tank cannot tolerate more than a few PSI of pressure. Thus the safe way to clear fuel lines is to remove the fuel cap, then pressurize the line from the front of the car back, in other words, remove the fuel line from the fuel pump inlet, and apply high pressure to it so as to force the crud back into the tank. Chances are, this crud will sooner or later have to be physically removed from the tank by removing the tank it and cleaning it out, but sometimes, whatever was blocking the line will just dissolve when you begin driving the car again, and ultimately show up in your fuel filter. Then all you have to do is replace or clean out the fuel filter – and this could be miles down the road if you’re lucky.

Pretty often, the blockage is right at the fuel pickup, inside the tank. In this case, you can remove the fuel line from the front of the tank and poke down into the fitting on the front of the tank with a very fine but stiff wire, like piano wire. If you can push the wire all the way into the pickup fitting (about 1 foot or so), you may clear enough of the crud to make the car drivable again, but there is a good chance you will puncture the sock on the pickup end. Of course, the sock is probably bad already; else there wouldn’t be crud in the pickup plumbing.

Again, sooner or later you’ll have to deal with this stuff, but you might be able to drive for a while before it finds its way back into a place where it blocks the fuel flow. If you like to gamble, this is a good way to feel the thrill of walking on the high rope!

Question from Marty (1959):

I let my '59 Imperial run out of gas for the first time in many years. The gas gauge has not been working since I had the gas tank redone a few years ago.  Now I can tell that she's fighting to get gas, like the line or something is clogged, then she stalls. How can I fix this? Please help, the car is stuck in the driveway.


From Demetrios:

I have heard that you may resolve the problem temporarily (or better if you are lucky) by blowing air backwards towards the gas tank from somewhere upstream the fuel pump. This will remove dirt from the fuel pickup filter. Again, be gentle with the pressure. I have never tried this but I was close when I had fuel starvation issues with my 68 LeBaron at WOT (my problems are gone for now).

If the inlet hose to the fuel pump is accessible, that may be a good point. I hope there is a gage in the tank so you know what the air pressure is. I do not think you need more than 10 psi or so. You can gradually increase pressure if nothing happens...

From Rob:

Start at the fuel pump. Use low pressure and gradually increase it. I used a little trigger chuck that I stuffed into the rubber line. Also take the cap off the tank so the pressure doesn't build up inside the tank. That would be bad. These are probably just temporary fixes. You're going to have to eventually replace/boil your tank.

From John:

If you haven't already replaced the inline fuel filter, that would be the first thing to do, regardless if you just did a few months ago. Running out of gas is not a good thing to let happen for more then the obvious reasons.

From Jeff:

When you had the tank redone, was it one of those clean and coat jobs at a local radiator shop? Or did you have it done by (spelling?) TankRenu? I used to work on a 40s Cadillac that had the problem every year or so, even after having the tank cleaned and coated internally. The stuff you can buy to do it yourself is just as questionable. The tanks flex, especially if there are any impact marks or dents in the tank, then the coating cracks and peels. The rust starts filling the filter or plugging the sock again. Running the tank really low, or empty, concentrated the contaminates and had them pulling into the tank sock.

The TankRenu process, or replacing a gas tank with a new one, are the only real "permanent" fixes that I have found.

RamChargers and other Dodge trucks had plastic socks that would swell shut in the 80s. We would pull the cap off the tank, take the rubber hose off that is the supply to the pump, and blow air in the line. We would blow the sock right off, you could hear the thing "thump" off into the tank. This was done after explaining the options to the customer and letting them make the decision whether to pull the tank, or blow off the sock. Food for thought.

Question from Raffi (1962):

I'm trying to get a 62 Imperial running again, its been sitting dormant for 16 years.  To try and get it started again, we fed gas into the carburetor manually and started the engine, sounds good. But we can't seem to get the gas from the tank to the carburetor and engine. We took out the fuel pump, and it needs replacing, so I'm getting a replacement from Napa. We blew into the fuel lines but I could not hear any bubbles in the gas tank, so I think there must be a clog somewhere. Is there a filter in the gas tank that might need changing? Varnish in the fuel lines? Is this hard to replace? Anybody out there know how I should proceed? 


From Steve:

You will probably need to pull the sending unit out of the gas tank. On my own car, I found the filter to be totally clogged and the gunk was so thick in the steel tube of the sending unit I had to drill it out. Also the gas tank was full of stuff that had to be from another planet... Stunk to high heaven and had about 1" thick layer of gunk on the bottom of the tank. I had the tank boiled out, coated inside and coated outside for less than $100. Radiator shops do this work.

From Jim:

Chrysler at one time had a "Lifetime" filter in the tank made of brass. I had the problem you describe with a 53 Imperial Town Limousine. Applying air pressure to the filler neck would cause the tank to "Balloon". It is possible, the fuel in the tank has deteriorated to the point, after 16 years, the tank will have to be removed and cleaned.

From John:

If you blow air from the fuel line back into the tank you should hear bubbling if there is any gas in the tank. Disconnect the fuel line
fitting at the carburetor and check that the brass screen isn't clogged. If you haven't done so already, open the rubber fuel line at the gas tank and blow air into the line to towards the engine. If you don't feel air where the line connects to the fuel pump you have isolated the clog to the line. Next, blow into the tank. If no bubbling or air noise in the tank, the filter on the tank pickup or the pickup line itself is clogged.

On a car that has been sitting this long, any water in the gas will cause the tank and lines to rust from the inside out. You should consider dropping the tank and getting it cleaned out and coated if needed. Also, blow the lines out really good with carburetor cleaner and compressed air until you blow out all the loose rust particles. I'd also suggest you get a carburetor kit and rebuild the carburetor. On a car that's been sitting for years, the floats will drop and stick in the bottom of the float bowls in gum residue holding the needle valves open. As soon as the engine spins up the carburetor will flood and overflow.

Once you get her running the next thing you should do is work on are the brakes. Even if they seem OK and you have good pedal, I wouldn't trust 'em. Replace the master, wheel cylinders and check that the linings haven't been saturated with old brake fluid before taking her on the road.

I went through a similar saga about 5 years ago on a '63 with 29K miles that was dormant for 25 years. Going through the brake and fuel system and changing all the fluids was all it took. Now it drives and runs like new.

From Don:

It's been my experience that anytime a car has been sitting that long, it is a good idea to take the gas tank out and clean it thoroughly. A lot of time, the gas tank only had a little gas in it which causes rust to form in the rest of the tank.  Sometimes it's best to put a liquid plastic liner in which can be had at most parts stores.  Once the tank is out, blow out the lines.  The pickup on your sending unit may be clogged.  If this is the case and you have to eliminate the screen, make sure you put enough fuel filters in the line so it will not wreck your new fuel pump.  Hopefully doing all of these things will prevent future problems.

From Steve:

Since I've "been there, done that", here's my 2 cents.  Replace the neoprene fuel lines for sure.  There's no way you should trust rubber/neoprene fuel hose 16 years old! Assume they're bad! It's a cheap fix. You're probably also looking at rust/clogging/sediment in the steel line. Blow these lines out while you have the rubber ones removed. Check the previous threads on rust in the fuel tank, you've probably got that too. If you don't (carefully) remove the tank and clean it, prepare to buy and replace quite a few (metal) fuel filters. IMHO, don't attempt to drive this car until you have confidence in a good fix and have thoroughly leak checked the fuel system. There's probably a lot of collective experience and wisdom out there on fuel issues, old cars get these problems. Engine fires ain't fun, don't take too many chances here!

Question from Jay (1962):

It was a hot day today in Ventura Co. CA. We took the '62 out from Camarillo to Fillmore (about 30 miles) in the mild morning heat. We turned the motor off for about 20 minutes and when we finally tried to start it again, it would start and die a few seconds later. I pulled the fuel filter and checked for a clogged filter, but that was okay. I used a little starting fluid (ether) to start the car for a couple second of idle with the fuel line disconnected at a point after the fuel pump. Seems the fuel pump doesn't pump anymore. Either that or it is vapor-locked, which I know nothing about. I could have a blockage in the fuel line somewhere between the fuel pump and tank, but I haven't had an opportunity to check that yet. I do have a new fuel pump for the '62 but I just haven't got around to installing it yet. It just might be time if the fuel lines check out okay. Anyway, we had the car towed home and the 28 miles cost us $100.00 OUCH! The day started off wrong and the '62 failing us ensured that the rest of the day would be a wash. Anybody have any ideas?

Reply from EL:

The fuel starvation situation is certainly one of the little joys of owning almost any classic car. On the 1959, the previous owner had a supplemental electric fuel pump installed to correct the situation. I added an on-off switch so that, before starting, I used the electric pump to fill the float bowl. Once started, I turned the electric pump off and drove normally. In instance of vapor lock, a turn of the switch overcomes it.

Question from Bob (1963):

Here's the problem...

My 63 runs fine until the fuel gets below 1/2 tank.... then if it is going uphill it sputters and kicks like it is running out of fuel and goes about 20 MPH top speed, but it doesn't stall. Once it gets to the top of the hill and levels out, it catches itself and runs fine again. I guess its a good thing I don't have very long hills in Atlanta!

Sitting in the garage, level, it starts and runs fine at all levels of fuel capacity, even at 1/8 tank.

The fuel coming into the carburetor seems clean and the fuel filter is clean, even after a few thousand miles.

I siphoned some fuel out of the bottom of the tanks and poured it through a cloth filter and it looks clean with not obvious dirt particles.

My theory is that the fuel pickup tube inside the gas tank may have a perforations in it, around the 1/2 tank level, and when I step on the gas going uphill at that level of fuel, and need more fuel pumped into the carburetor, it starts to suck air, and the engine gets just enough fuel to keep the car running, but not able to go uphill without rebelling.

Any other ideas or any experiences with a similar problem?

If this is the problem....

Can I get the line out of the tank without dropping the tank, or should I bite the bullet, drop the tank, and it cleaned and resealed, and fix the

line as well.... and maybe evening replace all the fuel lines while I'm at it?

Where can I get a replacement for this fuel pickup line?

Thanks for any advice or guidance on how to do this.


From John:

My guess is the fuel pump is getting ready to give up.

From Trace:

I just went thru this on my '63 Crown coupe. I replaced the fuel pump, most of the electronics, etc. The problem was in the tank for me. The car started out like yours and got so bad that it stranded me on a regular basis. A cruise around the block became impossible. I ended up dropping the tank, taking it to RENU, and now it runs great. They only charged me $175.00 to do the tank, with me doing the take out and install.

Question from Bill (1964):

Today is the BIG day, the very first time that I have been able to drive my '64 Crown Coupe that I got about 6 weeks ago. I just got back the very well done Master and Booster that I had Karp's rebuild. A friend installed it and got the brakes bled. I had neck surgery about 3 weeks ago and this is really exciting for me as it is only the 3rd time I have driven in the last month, plus it is the first trip in the coupe. It's road trip time!! We slowly and carefully drove down my road into town to feed her. $22.00 and some air in the tires, and we are ready to go. But wait. The attendant says there is gas running all over out of the tank. For the sake of safety, we carefully head back. I get back home and realize that it isnt coming out of the tank, but rather at the junction where the filler neck meets the tank. I didn't get down on the ground and poke around, as I cant do that stuff yet. Bending over though, it looks to me like there might be some gasket or something in between. Is this true? If so what is it? can I make a new one or is it something "special?" If so where can I buy one? Or is it just a fitting that I can snug up ? It will be a few more days before I can get down and play with this, but it is nice to be prepared. 


From Frank:

I think you may be talking about an O-ring that fits at that junction. I have not had to replace mine yet but I have heard it is an easy part to get and common to several years. I think someone even found one at a chrysler dealer believe it or not!

From Bill:

If it is coming from the filler tube, the sealing item is a grommet that fits into the rear opening of the tank, the tube goes through this grommet. It is a very snug fit that should not require any sealants (live RTV etc). Common to several years is right, easy to get, no. The original part number is discontinued at Chrysler. You just have to look around and find something that fits. They ARE still available from wrecking yards and Mitchell's etc.

Side note: When our tank was seeping fuel, further inspection revealed that it had a bunch of holes on the top surface. Not a pretty sight and very dangerous. A "new" tank was in order.

From Hutch:

I recently purchased one of those grommets from our local Chrysler dealer. The part number is 2880481. It lists at $12.25 and net was $10.41. (ie the grommet the fill tube for the gas tank goes into.)

Question from Carl (1965):

While attempting to remove the fuel line from the carburetor, the line snapped and now I'm looking for a replacement. Where can I get one for a '65 with a 413 and a Carter AFB?


From Norm:

Go to your local Pep Boys or equivalent. They will sell lines with fittings already in place. Your mission is to bend a new one to fit the contours of the old one. They will sell you a bending tool for about $5 and rent you a pipe crimping tool to put a flare on the end . I did this for the first time recently and it is no big deal.

From Jack:

Get an extra length or two just to practice on. 

Question from Tristan (1967):

I spent the day cleaning out the gas tank on my 67 imperial today. This is the second time this summer, and this time I did it properly. It seemed to be infested with some kind of fungi or plants that were growing in the fuel, and on the inside of the tank. This car has not been driven on the road since 1984, so they had a lot of time to grow. Anyway, I washed the tank out with water, and filled it up with small rocks, and shook it for a while which dislodged a lot of crap, but not all of it, so I took the rocks out, and washed it out, and dumped some hydrochloric acid in it. This made a lot of smoke, and started eating the crud, so I put some more gravel in it, and shook some more, and then just left it to eat away while I went to borrow a pressure washer. When I got back, I dumped out the acid, and rocks, and pressure washed the inside for about 90 minutes which removed pretty near all of the crud that was left. Then I dumped a bunch of laundry soap inside, and blew that around with the pressure washer, flushed it out, and filled it up with chlorine bleach. I let that sit for a while, and then dumped it out, and pressure washed the inside again. Then I dried it out, and dumped some alcohol inside, and set it on fire. When that finished burning, I welded over a couple of small rust holes I found in the top. Now, I'm tired, dirty, and my hands are sore, and I hope whatever was living in my gas tank is dead, and won't clog up my AFB again which it did last week.

Anyone have any ideas what was living in my tank that made such a mess?


From Jay:

The bad news it if you don't seal the metal surfaces inside the tank, you will be cleaning it out again - it's just a matter of time. I have used POR-15 Fuel Tank Sealer on ("in" really) our '62's fuel tank with good results.


They sell a kit for around $50 US that includes a special cleaner/prep and a quart of sealer. This stuff will permanently seal your tank from alien invaders without eating away the metal. After pouring in the sealer, sloshing it every-which-way-to-Sunday, and draining the excess, make sure you prop the tank up to drain every last bit of the excess. What doesn't get drained will be equal to lost tank capacity. If you use this stuff, you should never have contamination problems or leaks caused by rust or anything "growing" on the inner surfaces.

The fuel in my tank now comes out the same color as it was when it went in (at least until someone wants to do something nasty like adding something to the tank that belongs in a "B" movie!)

From Jim:

And your local radiator shop can also do the job, thereby saving you the mess. My local shop charges 50-60 bucks and the stuff is thick enough that it also seals any pinholes that may be thinking of opening up...

From Jim:

A friend recently had his tank cleaned & sealed. It was discovered, the in tank filter had also been sealed. The remedy was cutting a hole in the tank top, busting the filter out & welding the tank back up.

From Kerry:

And make sure you poke a coat hanger or something through the fuel outlet and vents. The stuff they use will also seal them closed.

Follow-up from Jim:

The suggestion to unplug the fuel line at the tank after sealing is a valid thought. I used a coat hanger for this in a '53 Town Limo, with success. When attempting the operation on a '55 Windsor wagon I ended up with the coat hanger remaining in the line. Undaunted, I fabricated a line from the tank drain, which worked fine until I backed over a parking space concrete stop, & broke the fitting on the tank. The Fire Dept. cleaned up the mess, the damage was repaired & I drove off as if I had good sense. ( A doubtful evaluation!)

Despite my embarrassment, the moral of this tale of woe is, "Use something other than a coat hanger to unplug the line." Perhaps "Piano Wire"?

Question from David (1981):

The fuel lines on my '81 Imperial have ruptured.  Anyone have any idea why?

Reply from Dick:

I'm not surprise the fuel lines ruptured -especially if the rubber hose was made before about 1997 (the new gas is death to the old rubber fuel hose, with marking before "SAE 30R7" on it. I think they're up to 30R9 or even higher now.) This is a safety issue for all older cars, by the way. Check your fuel and vapor hoses for the marking, if they haven't been replaced for a few years.

Follow-up question from 2D:

Do you think this is a problem for older cars with fuel pressure of only a few psi?

From Dick:

Yes, it is a problem for any car with rubber in the fuel system that has not been replaced in the last few years. This includes the mechanical fuel pump diaphragms, and in some cars, the needle valves in the carburetors. The cutoff for acceptable rubber types is around 1997 or so. All approved (read "safe") rubber hoses has marking on it to tell you if it is up to snuff - replace anything with a lower code number than SAE 30R7, and do it before you have a leak which causes a fire. Lower pressure in the lines maybe makes the leak a little slower, but any fuel leak is a problem. This can also cause vapor lock problems due to the leakage on the suction side of the fuel pump - it makes the fuel pump ingest air, which can lead to all kinds of drivability and stalling problems.

From Mikey:

On the subject of rubber hoses....fuel lines and water lines too, if they are 4 or 5 years old they are going south on you. I know there will be those who will scoff, but I've seen too many hoses that looked fine on the outside, then you flex one or give it a real close look and there are all those small cracks. This is especially true on fuel lines, radiator hoses do indeed go further...but then they "GO" when you least appreciate it. Just what we need when we have a car that is only occasionally driven on long trips.

From David:

YES!!! As was stated, the new fuels are very hard on older fuel hoses. I have had this happen on every car I have owned that was built before 1983.   I have a family friend who is a chemist for one of the "biggies" and he tells me that even if the gas is not oxygenated it re-formulated compared to gas refined even ten years ago due to EPA regulations. He says it has to do with how the gas burns and different additives needed for different locations, sea level, high altitude and weather.

From Don:

I don't really think the older fuel lines would affect the older cars.  The only rubber line I can picture on my '74 are the ones for the fuel filter and they come new with a new filter. 

When I replaced the fuel tank in my '89 EFI Mustang I didn't even think about it and just asked the parts store for a few feet of fuel line.  I had a brand new piece burst, so I went back and got the slightly more expensive fuel line for EFI cars.

From Chris:

It's not the fuel pressure, it's that modern gasoline additives like MTBE eat the rubber and will either leak or clog up your system.

Follow-up from Norm:

What am I missing here? No fuel system problems with any of my cars and I live in the west.

Reply from Dick:

Unless you are sure that your fuel hoses have been upgraded to current spec in the last few years, inspect each one for hairline cracks, or look for the SAE specification marking on each one. If the spec has a lower number than SAE 30R7, replace the hoses at your earliest convenience, because if they haven't failed yet, they soon will, with possible disastrous consequences.

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