How to loosen a stuck flare nut on a fuel line

[timsch]

First since it is a diesel it will not blow up as everybody seems to think when around fuels. Now heat the nut with a brazing tip so you don't spray fire all over then loosen your nut with a line wrench. Do be careful not to melt the line with the heat. Once loose then oil it up and grease when you put back on. This must be an inline filter to need the lines apart to change a fuel filter on a truck. Mine are all spin ons.

I wish it were a diesel. It's a T100, not a Hilux.

 

[Brown David]

First since it is a diesel

How did you come to that conclusion?

 

[Fixingfarmer]

So when cutting a fuel line gas or diesel I use a hack saw slowly. I’ve had a couple carb fires and things of that nature it’s not any fun when your shirt is on fire while you are stuck under a pickup. The other thing I’ve done is chewed through one with a snips. I’ve also used that trick on some fist size hydraulic lines at a place that liked to hand out hot work permits that took 3 days to fill out. Once the line is off you can even use a nice 6 point socket I think someone mentioned a wrench but it might be important to note that on a larger thing than this you can use an impact to break it loose at that point with the 6 point and rattle it. I have also used the 2 hammer trick with great success

 

[miangus]

I've got a fuel line flare nut stuck where it threads into the fuel (gasoline) filter. I've been soaking it with Kroil for about 3 weeks now and can't get it to budge. I've banged on it as well. Hitting it with the torch is out of the question. I've put about as much force onto the flare nut wrench that the nut will take without rounding off.

Any recommendations? I've got a 250W Weller soldering gun that I thought about coming to post this. I'm willing to try anything as long as it's short of blowing myself up.

Maybe heat with an electric heat gun. Heat the line spray with PB blaster, repeat. I saw a guy on the internet using this method to remove problem screws in a gun restoration, I tried it later and it actually works. I have used a torch on those GM filters along the frame rail, wrap a wet rag around the filter, gently heat the line just back from the filter, spray with PB blaster, repeat. Work on one side at a time. The fitting is corroded to the line. I also use locking pliers on the fuel filter nut. It provides a heat sink, and you are going to replace the filter anyway. I have used that method on brake line fittings for years.

 

[used red MN]

u razzed me, now i am wondering why u want to keep the nut on the old filter? just need a chunk of steel line and flare one end then connect it to the cut line with a union.

What “razzing” the cut-off your feet/governor deal? That was mostly said to make you go back and reread what was posted. I still don’t see how that guy could possibly blame the governor for his stumble problem. Like I said I’ll I’ll wait for him to pull a UFO out of it. Here those lines are likely metric fittings. I am not sure how readily available they are in parts stores in something 3/8 ish size equivalent. He said it doesn’t leak now and it should be able to reseal. If he can find a line that size with the correct threads I’m not going up there and lay under the truck with a gun if he tries to replace it.

 

[Texasmark]

There is a special wrench made to use on flare nuts. It is an extra heavy built hex end wrench with one hex side removed, that will slip over the copper tube.

I just bought a HF set of SAE and Metric....pricy (for HF tools) but seem to be good and sturdy.....and really pretty. I got them for diesel fuel line work.

 

[used red MN]

So when cutting a fuel line gas or diesel I use a hack saw slowly. I’ve had a couple carb fires and things of that nature it’s not any fun when your shirt is on fire while you are stuck under a pickup. The other thing I’ve done is chewed through one with a snips. I’ve also used that trick on some fist size hydraulic lines at a place that liked to hand out hot work permits that took 3 days to fill out. Once the line is off you can even use a nice 6 point socket I think someone mentioned a wrench but it might be important to note that on a larger thing than this you can use an impact to break it loose at that point with the 6 point and rattle it. I have also used the 2 hammer trick with great success

I just use a mini tubing cutter, usually you can undo the support clips or pop it out of them to get it away from the frame. Only need a bit over an inch.

 

[Fixingfarmer]

I just use a mini tubing cutter, usually you can undo the support clips or pop it out of them to get it away from the frame. Only need a bit over an inch.

that is a good idea most places that would slip in great.

 

[Tim PloughNman Daley RIP]

I've got a fuel line flare nut stuck where it threads into the fuel (gasoline) filter. I've been soaking it with Kroil for about 3 weeks now and can't get it to budge. I've banged on it as well. Hitting it with the torch is out of the question. I've put about as much force onto the flare nut wrench that the nut will take without rounding off.

Any recommendations? I've got a 250W Weller soldering gun that I thought about coming to post this. I'm willing to try anything as long as it's short of blowing myself up.

KROIL is just a snake oil product. Try PB-BLASTER or LIQUID WRENCH. Would not be 'hitting it with a torch' for dang sure -fuel + flame = disaster. Many booger up the flare nut wrench by using the wrong tool like vice grips or pliers and end up rounding off the HEX. A nut splitter comes in handy when all else fails. Fuel and brake lines use a SPECIAL THREAD SIZE too. 7/16-24 UNS, UNIFIED NATIONAL SPECIAL.

Tim Daley (MI)

 

[Dusty MI]

A long time ago Rust-Aid was very good at helping removing rust frozen nuts and bolts. By Detroit Efficiency Company.

Dusty

 

[tim s]

I've got a fuel line flare nut stuck where it threads into the fuel (gasoline) filter. I've been soaking it with Kroil for about 3 weeks now and can't get it to budge. I've banged on it as well. Hitting it with the torch is out of the question. I've put about as much force onto the flare nut wrench that the nut will take without rounding off.

Any recommendations? I've got a 250W Weller soldering gun that I thought about coming to post this. I'm willing to try anything as long as it's short of blowing myself up.

If you can get on it try putting a squeeze on the nut with a pair of vise grips , a bit of pressure to it may let it break loose,,

 

[Texasmark]

I do have a set of crow foot wrenches, although I'm sure they're metric and are HF, so not good ones....

The Chrome Vanadium Steel ones I just bought at HF were made in Taiwan.

 

[TerryfromSWIowa]

up on post 37 he said it is changed

 

[rustred]

up on post 37 he said it is changed

thats a good thing,... as i was starting to wonder whats going on taking a week to change a fuel filter. he would have lost his shorts in a garage on flat rate time.