Fuel Tank Drain

[tommyleea]

I planned on replacing the entire drain assembly on the fuel tank, but too much force required without movement, and I didn't want to twist it off in the tank. Now I just want to replace the small sediment bulb drain on the valve. It is tight also. Do these have a habit of twisting off in the valve, or will it break loose with some more force? Just looking for the risk vs reward. It has a drip every now and then, but I can live with it, if there is no chance of removing it. Thanks...Tommy 23 Roadster..

[Mark Gregush]

At the top of the sediment bowl are flats for removing the whole thing, put a wrench on them to hold it. The drain on the bottom is 1/8 NPT, while might take a little force to turn at first should not be that tight. Personally if all it does is a drip now and then, I would leave it. If you do replace it, I would use fuel proof pipe dope or Teflon tape made for same thing (yellow I think), not the while stuff (it is not fuel proof). Don't reef down when installing, just tight enough to prevent weeping around the thread.

[tommyleea]

At the top of the sediment bowl are flats for removing the whole thing, put a wrench on them to hold it. The drain on the bottom is 1/8 NPT, while might take a little force to turn at first should not be that tight. Personally if all it does is a drip now and then, I would leave it. If you do replace it, I would use fuel proof pipe dope or Teflon tape made for same thing (yellow I think), not the while stuff (it is not fuel proof). Don't reef down when installing, just tight enough to prevent weeping around the thread.

OK..Thanks Mark, that's what I needed to know. I am going to leave it..Tommy

[DanTreace]

Tommy

Drips of gasoline from your T should be stopped IMO, esp. if you park the T in an enclosed space.

The petcock drains on the crankcase oil drain, carb bowl and the gas tank sediment bulb are simple taper valve, held in place with a small spring.
A new petcock won't have wear and tear of an old one, as the taper can be worn, debris clogged, and rusted or poor spring to pull the taper valve closed.

Of course you can repair one, with some valve grinding paste to smooth the valve, and a new spring....or just buy new.
Removing the old, use some penetrating oil first at the threaded junction after wire brushing off old dirt or caked grease to allow the penetrating oil to seep in. Then remove twisting counterclockwise on the pipe threaded petcock. A smooth jaw adj. wrench placed over the body and lever works without leaving marks on the brass body.

One hint on seating the petcock valve is after twisting the lever to open and drain, the twisting it shut, tap on the end of the valve handle slightly to 'seat' the petcock valve. Helps seat it better.

As for the sediment bulb, same thing, that valve is like a petcock, just larger. You can repair seeps there the same way, or buy a new sediment bulb.

Use a tad of pipe dope on the threads, a gas proof sealer, IMO, Permatex #2 gasket sealer works very well.

[tommyleea]

Thanks Dan, Good info..Tommy

[tommyleea]

Tommy

Drips of gasoline from your T should be stopped IMO, esp. if you park the T in an enclosed space.

The petcock drains on the crankcase oil drain, carb bowl and the gas tank sediment bulb are simple taper valve, held in place with a small spring.
A new petcock won't have wear and tear of an old one, as the taper can be worn, debris clogged, and rusted or poor spring to pull the taper valve closed.

Of course you can repair one, with some valve grinding paste to smooth the valve, and a new spring....or just buy new.
Removing the old, use some penetrating oil first at the threaded junction after wire brushing off old dirt or caked grease to allow the penetrating oil to seep in. Then remove twisting counterclockwise on the pipe threaded petcock. A smooth jaw adj. wrench placed over the body and lever works without leaving marks on the brass body.


Petcocks .jpg



One hint on seating the petcock valve is after twisting the lever to open and drain, the twisting it shut, tap on the end of the valve handle slightly to 'seat' the petcock valve. Helps seat it better.

As for the sediment bulb, same thing, that valve is like a petcock, just larger. You can repair seeps there the same way, or buy a new sediment bulb.

Use a tad of pipe dope on the threads, a gas proof sealer, IMO, Permatex #2 gasket sealer works very well.

I removed the lever handle from the gas tank sediment bulb, and everything cleaned up. How much pressure should the spring have on the cotter key. Should you have to compress the spring to install the key, or just slight pressure and install by hand? Not sure if I need new washers and spring or not. Haven't located a rebuild kit. Maybe I could just vary washer thickness for correct fit? Thanks..Tommy

[DanTreace]

Tommy

The spring should be stout! The spring is what holds the taper valve tight to the taper body of the petcock or sediment bulb. To take mine apart, gently placed the petcock body between the bench vise jaws, and compress the washer on the face of the spring to get out the cotter. Install the reverse, works for me!

Unless your fingers are tough like guitar players, I choose the vise jaws or a pair of locking needle nose vise grips.

[tommyleea]

Tommy

The spring should be stout! The spring is what holds the taper valve tight to the taper body of the petcock or sediment bulb. To take mine apart, gently placed the petcock body between the bench vise jaws, and compress the washer on the face of the spring to get out the cotter. Install the reverse, works for me!

Unless your fingers are tough like guitar players, I choose the vise jaws or a pair of locking needle nose vise grips.

Got it..Thanks. No guitar player here, but my valve is still in the tank, in the car. Should be exciting!