Fuel Filter Nuts Corroded
 

Hi I finially decided to swap out my so called "lifetime" fuel filter on my 99' 4R SR5 with 160K miles and before I start I was warned by someone i trust at a dealer that its easy to damage the connections if not done very carefully... I suspect that the nuts are corroded due to the heavy chicagoland salting that occurs here.

Obviously a torch /heating is out of the question...

Any tips before I destroy my fuel line?

Also whats better at freeing rusted bolts? PB blaster, liquid wrench, or WD40?

Everyone seems to say PB blaster works best... yet I think I have cracked off more bolt heads with the PB blaster than anything else...? I never seemed to crack as many bolts with WD40? go figure..

Your concern here is based on Hollywood, not science or realistic risk.

There is no liquid, no fumes, and it won't combust inside the line from heating it.

Even if you take the fuel line off, with gas spilling from it, you won't be able to explode anything if you really really try.

Heat is still the best way to get rusted things loose without breaking them.

I was pretty much in the same position when I changed mine out. I used WD 40 and an actual line wrench. Just go slow. If it feels like your about to strip the nut, stop,spray and start over. The nuts were very soft on mine but, I was able to get it off.

I'm with you on the torch. It sounds like a receipe for disaster to me.

Ahhh! This is the worst project I've ever had come up on my rig (and I'm modding a Rav4 for the trail - everything is hard).

You're probably dealing with tubing of aluminum or light alloy (nut too), and the filter is going to be a hard metal, some steel alloy. These metals like each other a lot, and with fuel in the connection it'll slowly bind them. It sucks, trust me.

You might be able to do the flare wrench routine - it can work with perfect leverage, tons of patience and caution. I got the top connection on my 150K fuel filter that way. The bottom was a tricky ingress, though, and add to that the very friendly metals, I rounded the bottom fitting after two days of incredibly patient work. .

I have an alternative that worked really well, even if it was a little unkosher. One, go to a junkyard and buy the fuel line assembly containing the filter out of a donor vehicle. You NEED the lines in front of and behind the filter, at least a foot in each direction so you have some room to work. As long as the lines are good, you're fine - the filter from the junkyard is a throwaway (though you can keep the bracket). Cut those lines cleanly and attach them to the new filter and bracket assembly.

Now for the cool part. When you're dissecting the 4Runner fuel line/filter assembly, make sure to grab a foot or so of the OEM rubber fuel line that's in the engine bay nearby. That's your gold. A Mexican dude who could probably have put a 4Runner together with Zip-Ties and bubble gum showed me this trick - it's the factory fuel line, and it's totally fuel-proof. It's heavy, internally reinforced, and strong.

Then, instead of fighting the fittings on your old filter body, cut the metal line a little below the filter. Then you can use the new section and the old sections, join them in a much more convenient spot and link the two with the OEM rubber fuel line. I swedged both ends of the metal lines, and used two positive-clamping hose clamps on each end of the line, plus some Zip-Ties to keep things located nicely.

Fuel will spill, and I don't like the torch idea much, so be careful. Have a bunch of rags around and you'll soak drips up fine. If you're really worried, keep some sand or dirt in a bucket nearby (or a bunch of sopping wet hotel towels), because you need to smother a gas fire.

STICK your finger in it

To loosen the bolts, (northern Ontario=rusted) I just soaked it with penetrant for a few days prior to doing it as well as taking a wire brush to the threads to clean it up as much as possible. Once loosening it when i did get some give I would then tighten/loosen, tighten/loosen until it was moving nicely.

Make sure you use a line wrench on the line and another wrench on the filter itself so the line does not twist....I have never used heat on a fuel line.BPblaster and quick snap of torque....