How should I cut fuel line?

[Bryan]

In my 1999 Honda Civic LX (United States) I have a very slow leak coming from the fuel feed line. The section of fuel line is located closer to the rear of the car. I’m assuming the line is made of steel.

I was wondering if anyone could tell me what tool to use in order to cut a section of this fuel line which won’t create a spark and put me up in flames (keeping in mind the limited space around the fuel and brake lines that run together).

I’ve read in the Honda service manual how to relieve the fuel pressure (loosen fuel filter banjo bolt and open fuel filler cap). Is this all I need to do before cutting the line? I assume fuel will start flowing out where i make the cut which I am OK with.

Lastly, what parts will I need to replace the section of fuel line? I guess the parts store can tell me, but didn’t know if I should go with the nylon line and if there are pressurized fittings and adapters I would need.

Thanks in advance!

Topic

[Lorrin Barth]

I’d suggest ordering a new line from Honda. That way you don’t have to invent means of connecting the line and no cutting. Expect to have to do considerable work in threading it through but that is always the case.

[Daniel]

I agree. You’re going to spend as much or more buying couplers, tube cutters, and flaring tools as you would just buying a new line. Plus you won’t be adding weak points to an already old line. Heck, if the line is degraded enough you won’t be able to patch it and you’ll have to buy the new line anyway.

[Its me]

I am surprised the Honda manual suggest releasing fuel pressure by removing the banjo bolt… Yes this will work, but it will spray fuel…

If the car is still safe to start, I would remove the fuse for the fuel pump, turn on the car and let it run until the engine stalls… Fuel pressure relieved without fuel all over the place…

-Karl

[none]

[quote=”barneyb” post=132809]I’d suggest ordering a new line from Honda. That way you don’t have to invent means of connecting the line and no cutting. Expect to have to do considerable work in threading it through but that is always the case.[/quote]

This is good advice. The other problem with trying to patch those old rusted line is that every time you try and fix one spot, you’ll agitate another point in the line that’s also weak from rust. Look at all those clips that retain your lines an you’ll notice there’s more scaly and bubbling rust build up at each one. Those are your next leak points waiting to happen. There’s no point in telling yourself you’ll just be careful. You’ll have to flex and stress those lines and you probably will create another leak before you finish fixing the first leak.

[Bryan]

I just wanted to post my fix. Great points were made on just replacing the entire line. The line was rusty from the front of my car to the back.

I went ahead and bought the following:

+5/16″ nylon line made by dorman. I determined the diameter that I needed by simply seeing which of my wrenches fit onto the fuel feed line. 8mm = 0.314 inches.

+2 steel to nylon brass adapters made by dorman.

+Fuel filter.

+5/16″ steel line with the fitting that goes into the bottom of the fuel filter. Also made by dorman.

+Tubing cutter (bought the 7pc set from Harbor Freight).

+Heat gun in order to fit the nylon line onto the adapters.

Before beginning be sure to relieve all fuel pressure! I described how to do this in my original post.

Replacing the line was easier than I thought. I first lifted the back seat bottom cushion up enough to gain access to the access plate. Only one 10mm bolt needed to be removed that was tucked in between the bottom cushion and the back cushion in the back seat. You might find a couple dollars worth of change or some really old McDonalds monopoly pieces like I did.

4 phillips head screws needed removed to open the access plate. Under this plate is where the fuel pump can be replaced if needed. I removed the quick connect fitting from this small fuel feed pipe. The small fuel feed pipe is what goes into the tank (or pump, not sure). A diagram is in the Honda Service Manual which you should find for a 99 civic somewhere on the internet.

I then fed the nylon line through the access plate area to the left side of the car where the fuel feed line is exposed. I got my steel to nylon adapter ready along with the nylon line. By hand, I fit the nylon as far as it would go on the fitting (not far) and worked it on by heating the nylon end with a heat gun and pushing it on, repeating until the nylon line was all the way on the adapter.

With the compression fitting, I fit the steel side of the adapter onto the fuel feed pipe underneath the access plate, tightening down as far as I could without breaking the fuel feed pipe.

I fed the nylon line along side the brake lines/fuel lines that run along the bottom. I wrapped zip ties around the nylon line and the other lines to support it.

I wont walk through how to replace a fuel filter. I actually did this part before starting underneath the back seat. The Honda Service Manual describes this in detail. Be sure to use a flare nut wrench for the line.

I cut the new steel line to only less than a foot. This is where the flared end went into the new fuel filter and the other end I cut with tubing cutter which would later fit onto the steel to nylon adapter.

Then I pulled the nylon line up around the sway bar through the components underneath the hood. I cut the nylon line where I was going to connect the new steel line to, being sure I had a little bit of slack just in case I screwed up the steel to nylon connection. I kept the old line underneath the hood and rested it on the upper side of the fuel filter for whatever reason.

I tightened everything down, put the fuel filler cap back on, and made sure I had no leaks. First I tried just turning the key to the ON position to just run the fuel pump without starting the car. I did have to further tighten the steel line adapter under the hood.

Everything still works. I actually just started driving my car more regularly today. I was lazy and let my car sit a while outside before doing this repair. Rust was not nice to me and I had to replace both the front disc brakes and rear drum brakes since the car was sitting a while.

I guess the only downside to using nylon might be that the possibility of the line getting kinked up is a little greater. Im not sure. I just didn’t want to deal with bending steel lines myself.

Sorry for the long post. I hope this helps somebody looking to replace fuel line since there isn’t much material on doing such a repair like I did. God bless.

[Author]

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