Changing Fuel Filter

OK, stupid questions on changing the filter.
The car has been sitting not started for 3 weeks -when I disconnect the line can I expect fuel to run out?
More importantly, how do I properly disconnect the fuel filter lines without bending then?
I have PB Blaster on the two nuts right now - put a wrench on the small nut closest to the fuel line and hold it steady while I back off the larger nut to the carb? Is that right and if so, to loosen the larger nut is it clockwise or counter clockwise to loosen while I hold the smaller nut steady?
Thank for the help - I checked the 350 threads back to 2009 with nothing mentioned so I know this must be a stupid question!
Dave

 

Actually a very good question. As simple as changing a filter is, some folks get into all sorts of troubles doing it.

USPS just dropped off another casting today for a heli-coil insert, we do hundreds of them each year.

The most common problems encountered during this simple evolution are twisting" the steel line, putting the filter in first then the spring, cross-threading the filter housing, loosing the gasket, and putting the filter in backwards.

Using a 1" open end wrench, hold the fuel filter housing. Using a 5/8" tubing wrench, loosen the fuel line nut. Remove the nut and fuel line, then loosen the fuel filter housing.

Inspect the gasket, and replace if/as needed.

Inspect the spring, replace if it's rusted or damaged.

Install the spring first, then the filter, open end toward the fuel line. (Very early units use a bronze filter, open end toward the fuel line and it seals on a gasket against the back of the fuel filter housing.)

Carefully thread the fuel filter housing into the carburetor and tighten snugly against the gasket.

Install the fuel line nut and tighten it while holding the fuel filter housing from moving. It's a good idea to use a drop of lube oil on the threads.

Do NOT use teflon tape on any fittings. it is NOT needed, and will find it's slippery way into your carb causing MAJOR running issues. The fuel filter housing seals on the gasket, the fuel line nut tightens the double flared steel line against the inverted flare inside the fuel filter housing.

Start the engine and check for leaks.

If it leaks between the fuel filter housing and carburetor, tighten the fuel filter housing. It is best to loosen the fuel line before doing this.

If it leaks at the fuel line nut, hold the fuel filter housing securely and tighten the fuel line.

Be aware that the 1971 and older carbs have the fiber gasket that seals at the front of the carb on a machined surface at the base of the 1" nut. This has fuel in the threads and errodes them out over the years. Pretty common to see them stripped out.

The ONLY effective and permanent repair for stripped threads is a heli-coil and re-using the stock housing.

The oversize fittings, and expanding fittings can, and will ruin your carburetor.

The oversize fittings use up good material needed for the heli-coil insert.

The expanding fittings "bell-mouth" the nose of the carb, making it difficult, if not near impossible to make a good repair with a heli-coil.

1972 and newer carb (except Marine units) will use a plastic seal at the end of the threaded portion of the fuel filter housing. This is a much better deal, and give no troubles unless the fuel filter housing is cross-threaded.

That about covers it.....Cliff

 

Good posting Cliff -
It's a very simple procedure that can turn into a major problem, and ruin a carb if you happen to cross thread, or over tighten that filter housing !!
( . . . don't ask me how I know :af: ) :gp:

 

Cliff - A big thank you! I would have never known about all the points you listed beyond just getting the line open to change the filter - none are listed in my crash book. I am learning to wrench on these and your detailed reply is really appreciated!