How to loosen a stuck flare nut on a fuel line

Is it this one?



I've had good luck using two hammers.

One on the back side flat of the black nut on the filter and smacking the front side flat with the other hammer, rotating around the filter as much as possible.

Do the same to the nut on the line if it is frozen to the line.

Probably not a lot of room to do that but repeating the process a few times helps.

Maybe that's what you meant when you said you tried banging on it.

EDIT: Jim. ME beat me to it.
 
Is it this one?



I've had good luck using two hammers.

One on the back side flat of the black nut on the filter and smacking the front side flat with the other hammer, rotating around the filter as much as possible.

Do the same to the nut on the line if it is frozen to the line.

Probably not a lot of room to do that but repeating the process a few times helps.

Maybe that's what you meant when you said you tried banging on it.

EDIT: Jim. ME beat me to it.
That is the one.

I'll try this tomorrow. My banging on it so far has consisted of me just hitting both the nut and the filter with my adjustable wrench. Y'alls idea is better for sure.

Thanks to everyone for their suggestions.
 
Sorry to be unclear. It's my '98 T100 truck with steel lines going into my fuel filter.
Toyota fuel injection filters are naturally hard to break free nature of the beast. I would rattle free are take it to someone who's tooled up for the job. Not all flare nut wrenches/sockets are equal cheap ones will make a mess.
Sorry to be unclear. It's my '98 T100 truck with steel lines going into my fuel filter.
Toyota fuel injection filters are naturally hard to break free lucky you you have one of the easy ones to get at.
At 3:09 I am shocked he used that big of a impact a 3/8 air are battery will git'er done.
 
I just meant I liked the idea used red MN said about cutting the line and slipping a deep socket over it to break the nut. I'm making a list of things to try and in what order, at least in my head.
i was replying back to him . asking why he wants to keep the nut . once the line is cut just replace the filter with a new one as i presumed you are doing, and dont worry about that fitting,.. its of no use. you will be using a new fitting with a new chunk of line and a union to join to the old original line and not worry about that old damaged fitting leaking. i am talking a professional job for a gas line repair.
 
Toyota fuel injection filters are naturally hard to break free nature of the beast. I would rattle free are take it to someone who's tooled up for the job. Not all flare nut wrenches/sockets are equal cheap ones will make a mess.

Toyota fuel injection filters are naturally hard to break free lucky you you have one of the easy ones to get at.
At 3:09 I am shocked he used that big of a impact a 3/8 air are battery will git'er done.
Yikes!! That's the exploding part I'm trying to avoid...

Yeah, I'm being a wuss, and the fuel is well sealed in the line and filter, but out of respect for what gasoline and fire results in, I'm not allowing myself to go there. No Darwin award for me.

I do have a friend who's a mechanic who could take care of it if need be.
 
If you had a picture of as it sits on the truck might help with suggestions.

If there is room you could cut the line, put a new flare nut on it, flare it, then replace the section cut out with a short new piece and join things with a union. I've done that a lot with brake lines.
 
If you can get onto the female part of the nut,clamp a set of vice grips onto two opposite sets of flats,,real hard.Like you want to crush it.If you can do this on 3 sets of flats you may be able to distort it enough to break the interference between the parts.Although it's not the proper way to do things,I do have pretty good luck just using two pair of vice grips to break things loose.
 
If you had a picture of as it sits on the truck might help with suggestions.

If there is room you could cut the line, put a new flare nut on it, flare it, then replace the section cut out with a short new piece and join things with a union. I've done that a lot with brake lines.
The video in post 21 shows it. Access is very good.
 
If you can get onto the female part of the nut,clamp a set of vice grips onto two opposite sets of flats,,real hard.Like you want to crush it.If you can do this on 3 sets of flats you may be able to distort it enough to break the interference between the parts.Although it's not the proper way to do things,I do have pretty good luck just using two pair of vice grips to break things loose.
Good idea to try that on the filter flats. I've thought about a pair of vise grips on both, but decided against it at the time. Still should try it before any cutting.
 
The video in post 21 shows it. Access is very good.

Is there enough room on the straight section towards the gas tank to get a small tubing cutter and flare tool on the line? Could bend the line out if needed after cutting it to flare it. Then make up a short curved piece and use a connector.
 
Access might be good but up in the frame rail I'd expect you'd probably be able to hit it harder with a purse than a hammer.

What about rattling it with an air chisel with a blunt hammer bit in it? Back it up from behind with a hammer or whatever solid metal you can fit, and give it a burp or two on the filter hex.
 
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.
One trick I have used when excess force is needed on a tubing wrench is to clamp Vise Grips tightly over the wrench to keep it from spreading or breaking.
 
Much appreciation for the great tips y'all are giving me. Fortunately, I've got the tooling to do about all of them. I should be able to get back to it no later than tomorrow. Hopefully I'll be reporting good news about not having to cut anything...
 
Line wrenches are one of the few tools where snap-on prices are worth every penny. Others fail at much lower torque, rounding the nut or don’t fit well , also rounding the nut. Full sets aren’t worth the price but a couple of real common sizes are. Like 9/16 x 1/2 and then 3/8x7/16 on our old stuff
 
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 are able to hold the filter from turning, use a "line wrench" on the flare nut.

If you cannot get it off cut the nut off. Then then cut the flare off of the line, put on a new nut, then re-flare the.
 
Thanks again for all of the help.

I put a hammer on the backside of the filter hex and hit a couple of flats on the opposite side.

After that, I put my flare nut wrench on the line nut and clamped that with the Vise-Grips as Steve recommended. It wouldn't move, but then I put a cheater pipe on the wrench and got it done. I wouldn't have put that kinda torque on it withoun the Vise-Grips on the wrench. Great solution.
 
Thanks again for all of the help.

I put a hammer on the backside of the filter hex and hit a couple of flats on the opposite side.

After that, I put my flare nut wrench on the line nut and clamped that with the Vise-Grips as Steve recommended. It wouldn't move, but then I put a cheater pipe on the wrench and got it done. I wouldn't have put that kinda torque on it withoun the Vise-Grips on the wrench. Great solution.
That's a cool trick, if my impact did not rattle it apart my induction heater would have came out. Not only do those metric fittings come apart hard most go back hard. Prior to later frame mounts Toyota use to bolt them to the block the starter had to come off if not there under the brake booster. Neither were easily accessible.
 
Another battle plan this snap on line tool are the EZ Red. The snap on the more pressure the tighter it gets.
 

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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.
 

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