stuck flare nut on fuel filter

[Dwsewell]

Well, it looks like another easy project is turning out to be much more difficult than anticipated.

I am using two 19MM wrenches, a flared wrench on the outside nut and a regular 19MM on the banjo nut. I started by using two stubby wrenches but it didn't cooperate. I bought two larger wrenches (about 8" long) and the thing still won't budge. In both cases I soaked it down with PB Blaster a couple of times, including once overnight. I even used a rubber mallet to try to persuade the bolt to give.

Before I spend more money buying the longest wrench I can find does anyone have any suggestions on a way to get this damn thing off?

[Linderpat]

Don't buy a longer wench, use the shorter, smaller one and fit a pipe over it for additional torque leverage. The real issue is destroying that flare on the fuel line itself, which could cause a fuel leak after you attach the new filter. I've had this happen too, and used what felt like a hell of a lot of force to beak it open, and found no issues later. Good luck.

[husker boxster]

You don't say specifically but based on your description it sounds like you're working in the filter out nuts. Those were some of the hardest to brake loose in my recently purchased 87 S4, the other being the line into the gas cooler on the firewall. Using a flare wrench on the outside nut is the way to go. Also assume you're making a small V with the wrenches and trying to squeeze them together to break the nut loose? Using a hammer is OK as long as you keep an eye on the outbound fuel line. Don't want to kink it.

I use AeroKroil, which has a bit of auto trans fluid in it. ATF has been found to do a good job breaking nuts loose. Keep soaking overnight if necessary and trying.

[JK McDonald]

Hey Dwsewell - When trying to break loose a cantankerous old fuel filter, you might try using a couple of medium sized crescent wrenches. They often work best for me.

Gently rock each crescent wrench on the fittings as you adjust their jaws up good and tight. Make sure to flip the wrench handles around on each end of the filter (making a "V" as Husker mentioned) where they oppose the other. Squeeze the handles together to break loose each fuel line.

When installing the new filter - snug everything up - then before you start the car, turn the key ON/OFF a few times to pressurize the fuel system and check for any leaks. Tighten the fittings if needed.

Good Luck - Michael

[Dwsewell]

It's amazing how frustrating one nut can be. I have not been able to come up with a pipe for leverage (can't go many places here currently) but did get some crowfoot flared nut wrenches (just the heads) combined with a breaker bar and a long torque wrench and it still won't budge. I've formed the "V" and instructed. Unless I should be turning the outer flared nut (not the banjo nut) clockwise, it's just not budging.

I haven't tried ATF yet, but will tomorrow. I haven't been able to locate AeroKroil to try it. I've used a ton of PB Blaster.

Michael, thanks for the advice on pressurizing the fuel system when I do get the new one on.

[stepson]

It is much easier to work on that fuel pump stuff on the work bench. If you remove the nut on the end of the filter and remove the clamp on the hose coming from the tank, you can loosen the 10mm nuts on either side of the rubber mounts that hold the whole assembly to the car, and remove the whole assembly as one piece and work on it at the workbench.

#1 You have taken a pretty good picture to refer back to for reassembly.
#2 When you remove that hose clamp and hose, any fuel in the system is gonna come out. Be prepared for that.
#3 DO NOT BEND the metal line between the pump and the filter.
#4 Reassembly is the reverse of what you have done to get to that point.

Good luck.

[Dwsewell]

Looks like you are seeing all of my challenges Stepson.

I was planning to do just as you've said, but I cannot get the flare nut on the filter removed to save my life. That's the hang up that is preventing me from getting to the next steps.

[stepson]

Originally Posted by Dwsewell

Looks like you are seeing all of my challenges Stepson.

I was planning to do just as you've said, but I cannot get the flare nut on the filter removed to save my life. That's the hang up that is preventing me from getting to the next steps.

Yes, I have been around these parts for a while now, and have had 8 of these beasts. Most of them needed work, sometimes a lot of it.

You have done right by walking away for a bit to clear your mind and let your body rest and recoup a little.

Any chance that you get a second set of hands to help? I would have the help hold the filter and the nut that doesn't turn on the filter stationary, while you use whatever means necessary to turn that dang flare nut. Even if you have to wait for the weekend for help, it might be worth it.

[honerboys]

if you have a set of box end wrenches ..there's a way to interlock the box into a flare to get you a pretty long wrench for leverage - like this

[BoxsterGT]

Over time, we all have seen frozen fuel line fittings. It may be a good procedure to use a little Anti-Sieze on the threads.

One thing I am sure of, many of us tighten these fitting too tight. The flare or ball & cone design allows it to be "snug", plus a little.

When tightened more than that it is asking for trouble. These are NOT tapered pipe threads which get tighter the more you turn the hex nut.

Len

[Dwsewell]

Don’t know whether it was the ATF or having help (got the wife to hold the other wrench) but I was able to get it off with a crows foot head and a breaker bar. I tore up my hand pretty good but it was worth it.

[stepson]

Sorry about your hand, glad to hear you got some good help and got it loose.

[husker boxster]

Congrats! Sounds like it was a combination of 3-4 things. And remember...

Chicks dig scars.

[Linderpat]

Congrats. I have a saying with working on these cars - if you're not bleeding, you're not working!

[Dwsewell]

Chicks to dig scars! Thanks for the help everyone.

[harborman]

Sometimes a good smack with a hammer on the end of the wrench can break it loose.

[husker boxster]

I mentioned this was the 2nd toughest connection I had trouble with on my S4. When my filter nut finally broke loose (and it happens suddenly), I somehow smacked my left hand with 1 of the wrenches. Hit it right below the pad below the pinkie finger (where the crease line is). It hurt for several days, which was OK. The real problem was since then (Dec), my pinkie finger "catches" when I fold it. Sometimes it catches when I unfold it. It's particularly balky first thing in the morning. Kind of wonder if I broke something.

Chicks are less enamored with a balky pinkie finger.

[Danglerb]

Aluminum to Aluminum seems like it welds itself together. Other than it being iirc a fitting with 17mm and 19mm on the other side, I don't remember what the specific hose from the front was, but we cut the hoses to get it out and for a week or two it was "the sword in the stone" around the shop to see who could break it loose. Eventually I used a box end and a long handle flare making a V, then tied a rope around the wide end, put a wrench into the rope loop and started twisting the rope to pull the wrenches together, worked, no blood spilled.

[honerboys]

^^^^^ clever ^^^^^

[BoxsterGT]

Another point I forgot to mention, but thought of when a friend wanted to change the Inlet fitting on his Fuel Filter.....

Bosch and perhaps others use a form of "Locktite" on both ends of their filters. The only way I and others have found to get these fittings off is to warm the joint with a Propane Torch.

I know, its a fuel fitting, but as the issue is being tight, there will be NO fuel leak.

The heat will break the "Locktite" bond and it will come apart easily.

Edit- This is the Flare fitting on the filter itself, when on the bench, not while it is on the car.

Len