carnahanbb

I'm getting ready to replace my fuel lines. I have everything I need including never seize and the Porsche and Greg Brown lines. My question is mainly concerning loosening the existing lines. I've read a few different places that they can be a bear to break loose. I don't want to strip, damage or bend anything. Should I just save this job for a professional?

MainePorsche

Flare wrenches are practically specific for this job of countering holding and loosening. If not familiar google. They hold the 'nut' in a more circumferential manner.

dr bob

Definitely a good DIY project, easily within the ability of most owners. As directed above, use --good-- flare-nut wrenches on the tubing connections. Inspect everything as it comes apart. Do everything you can to avoid nicking any of the sealing surfaces, including barbs and flares, when removing old hose. Good Idea to take pictures of how things are arranged before you start stripping pieces out. Do one or two easy sections at a time, so you can remember where they go and how. The WSM gives torque values but they are difficult to measure and get right for the tube fittings. There are crowfoot flare-nut wrenches you can use with a torque wrench. Most leaks I've seen in fuel fittings, especially ball-flare junctions, come from someone tighhtening things too much rather than too little. Once overtightened, it gets tough to keep a good seal on those fittings. There's a recommendtion to use some Loctite anaerobic gasket maker (274??) on those fittings if they get damaged from misalignment or overtightening.

Very Important:
When you have everything together and all the connections are correctly snugged up, reconnect the battery ground, and put a jumper in the fuel pump relay socket so the pump rund continuously. Then go back through every connection and coupling to make sure there are no leaks. I had a tiny one that was only discovered with a finger or paper towel, wrapped around the connection for a bit. Sniff the probe for fuel stink.

After each connection is verified for correct torque and no leakage, it gets a dab of paint pen or nail polish to show a QC pass. I buy cheap nail polish at the Rite Aid for such duty, since it comes off so easily later with a little Brake Clean. I think you can see the maintenance and service history on many parts of my car, documented with a rainbow of color spots on various fasteners and connections.

worf928

+1,000,000

Never, ever, skip this step.

MainePorsche

As Bob mentioned the anaerobic Loctite, it is Loctite 574. It is not cheap, but it is worth its weight in gold. A tale if you'll permit. I have had my manifold off numerous times and was always careful about fitting the 'ball' of the fuel rails to the 'cup' of the regulator/dampener. One time I slipped while reaching over to do, and I knocked the ball against the edge of the cup on the damper side. This caused a small linear knick on the ball. I spent hours of fine symmetrical sanding with something like 600 sandpaper. Even with a magnifying glass I couldn't see the defect, but still had a miniscule leak. I started a thread to get help and Greg Brown said stop and get some Loctite 574. Said he uses this in his shop and unions don't leak. Sure enough he was correct. I apply a small amount to the cup side with a small soft device I use in medicine. You could just use something soft like a toothpick and add a thin coat to the cup side without letting any go in the hole. Join (no need to over tighten - it only hurts and doesn't add anything - check torque values), let cure for about an hour and you'll be good to go. This stuff works very well. OF COURSE YOU WILL CHECK FOR LEAKS NONETHELESS. You won't find them though. 574 cures fast so don't leave the cap of your new expensive sealant while working. The WSM calls for it for other application where you have a metal to metal flange joint. I had used it when I replaced the cam journal plugs to pins on the bridge.

SeanR

It doesn't matter if it's factory hoses, Gregs hoses or something that I come up with. I always run the pump for a good 20 minutes looking for leaks before that engine even cranks over.

Please save yourself some grief and test them for leaks. After your first test drive, go back and look at them.

kos_007

All good advice here. Just make sure you don't have a leaking injector. Running the fuel pump for a long time without running the engine and having a leaking injector poses the risk of hydrolocking the engine. So, after jumping the pump sniff around the intake, MAF opening with the air filter removed - I would not start the engine if there is any hint of raw fuel smell. Also disconnect the vacuum lines from the fuel pressure regulator and dampers to smell for any fuel once the system is pressurized.

The Deputy

Not sure what year car you have, but I usually cut the existing fuel lines with a razorbalde, the rubber portion, as close to the fittings as possible...then that allows you to use a boxend wrench or deepwell six-point socket in some cases. Cutting the rubber portion also allows you to wiggle the fittings around into a better working position, too. Line wrench crows foot will work okay, too.

Good luck,

Brian.

carnahanbb

Thanks for all the helpful information! The tips about the flange wrenches, Loctite 574 and jumping the fuel pump relay are really helpful. I hadn't come across the idea of jumping the relay socket to get the pump to run continuously. Do you know what parts I need to jump to accomplish this?

Also, with regards to the flare wrenches I hadn't checked what size the nuts on the fuel lines are and I would like to try to pick up some flange wrenches today over my lunch break and would like to make sure I get the correct size wrench. Do you know off the top of your head what size the nuts are? Lastly, is there a difference between a crows foot wrench and a flange wrench?

NoVector

[QUOTE=The Deputy;12809337]... Cutting the rubber portion also allows you to wiggle the fittings around into a better working position, too. /QUOTE]

When I did the top end refresh and replaced all the fuel lines with Greg’s, I had a problem threading one of his hoses to the fuel rail. Apparently the threads on the rail had been flared by a PO’s overtightening. So, I had to put the old hose back on until I got that sorted out. If I had cut the old lines, I would’ve been waiting a while. Greg mentions the flaring in his hose instructions.

For the OP, not trying to spook you as I doubt it happens very often. But it can happen. Good luck!

dr bob

A flare-nut wrench is a lot like a box-end wrench with a small section cut out to allow it to fit over the connected fuel line. Having the gap there means the wrench needs some extra meat to maintain support.

A crows-foot wrench is typically and open-end wrench with a square-drive next to the opening for the nut, so that a regular ratchet and extension can be attached. The open-end wrench part then has legs that stick out sideways when looking down the ratchet/extension, hence the 'crows-foot' moniker.

A crows-foot flare-nut wrench is the hybrid of those two wrenches, like the regular open-end crow's-foot but with the extra wrap-around part like a box-end with the section cut out. That lets you use a torque wrench on a flare nut to get the tension just right.


Flare-nut wrenches are used on hollow fittings and compression nuts to avoid having the piece collapse and get rounded off from pressure applied to just two of the six corners of a fitting. The better flare-nut wrenches are broached with a littl convex face for each flat on the fitting, and they fit relatively snugly. The wrench typically 'grips' five of the six flats so much less chance of rounding and/or collapsing the fitting.

carnahanbb

Awesome information. It's amazing just how much knowledge there is here on RL. I'm heading to check them out tonight. I don't need professional level gear but I'll see what I can find.

dr bob

If you are working to populate your stocking-stuffer list, look at these:

https://store.snapon.com/Double-End-...--P630591.aspx


For most of us, there are much lower cost options available from discount places like Amazon or your local parts store. I happen to really like the flank drive on the Snap-On wrenches.

I'm pretty sure that the Snap-On set I bought 40+ years ago wasn't nearly as spendy as their current offering. Of course, the $30 or so I paid for my now-antique set was worth a lot more then, when minimum wage was about $1.50/hr.


----

These swivel-head crows-foot flare-nut wrenches would be a nice addition too. Under $50 for the set. Way handy for getting to the brake line fittings between the rear wheels, for instance.

WallyP

Do not buy cheap or no-name flare wrenches! This is one place where Harbor Freight tools do not work.

The is about as much quality difference between Craftsman and Snap-On (or similar pro tools) as there is between Harbor Freight and Craftsman...

carnahanbb

Dang! That Snap-On set is really expensive...like 10X as expensive as Harbor Freight.

The second set you linked to looks really useful. Is there any reason I wouldn't want to use a socket wrench flare nut adapter instead of just a flare wrench?