Fuel Selector Diagrahm?

[David Rounds]

Just ordered an o-ring kit from webco to rebuild one of our fuel selectors on the twinkie while the fuel pump is being overhauled. I checked in the parts and service manuals and there really isn't a good exploded view of the selector. Once I start it may be self expanatory but was curious if there is a good diagrahm out there that someone can pass on?

Thanks,

David

[md11flyer]

David here is a post from several years ago from a member who went through this process as well. It gives you a bit of info on the process involved.
Hope this helps.
Gary

"Don't know if you have run into this problem yet, but assuming you have not I will present a recent and the first I have had. The PA-30 that I purchased three years ago had been sitting for 14 years in a hanger. Many of my on going problems have been dried out gaskets and "0" rings. Recently I have had a very slow leak of fuel from the left aux tank. It resulted in a blue stain 3 inches forward of the front fuel sump (left engine). The leak was so insifnigicant as to not drip on the hanger concrete floor. (Evaporation) occured on the belly of the plane, however if I had not flown the aircraft for a week (with the plane sitting and alll 4 tanks full) the left aux would be down about two gals of fuel. I always shut fuel valves off. Thus I had two problems. One, the aux fuel inlet to the bowl was not sealing, and two, their was an external leak from somewhere in the sump assembly.

I removed the selector valve and the assembly. It is not necessary to remove the top bracket that holds the valve. That top plate or bracket supports the valve. Removing the top screws (I think there are six) and then removing the top red button and then four fuel lines to the valve will allow the valve to drop out and be removed. After the aluminum fittings are removed from the valve (aux, main, and cross feed fittings), you can then look inside each of the three holes. Looking from the outside in you will note a split washer that looks as if it may have been screwed in the threads (it is not) I made a tool from a five inch BARN nail. I ground down from the tip one half inch up so that it was 1/16 th flat and one half inch long. Then bent the tip to 100 degrees (making a hook). You can then insert this behind the split washer, and be certain that when you insert it that it is opposite the split opening, and then you find that you can lift the split ring out. Be careful since when you pull the split ring out that the spring (conical) in shape is not lost. Remove the spring with the same tool. When removing the spring you will find a ball bearing. Remove the bearing. Then you will find another split retainer ring. That ring is the retainer for the "0" ring behind it. Using a awl you can remove the "0" ring first and then the split retainer ring. (Note the split retainer ring is JUST large enough to allow the ball bearing to seat against the "0" ring but not large enough to allow the "0" ring to be pushed out. When the selector arm is rotated to the off position none of the fingers inside the valve are pushing outward against the ball bearings. When the selector arm is rotated from the off position then the internal finger presses against the aux ball bearing allowing fuel to pass the ball into the valve assembly. Rotating the selector valve further then presses the finger against the main ball bearing, further rotation of the selector arm presses against the Cross Feed ball allowing fuel to flow from the cross feed ball internally. Once any one of the ball bearings are pushed in by the internal finger, fuel flows to the outflow fitting which then routes the fuel to the boost pump. If the boost pump is off the fuel then flows to the engine. If the boost pump is turned on the fuel pressure is merely boosted.

My problem (two fold) was a very dried out "0" ring on the Aux inlet fitting and then also a leaking gasket between the (dog bowl and the upper valve assembly) The leaking gasket turned out to be the result of the previous owner replacing the gasket with a thicker type gasket) I specifically mention that this should never be done. As in this case the thicker gasket allows the upper flange to bend when the # 10 screws are torqued down. Not only should these screws be over-torqued but the gasket should never be replace with a thicker one. The upper flange of the "dog" bowl is only about a 32nd of an inch and easily distorted. "

[Kristin Winter]

There is no diagram or instructions for repairing the fuel selector. There are only a couple of shops that are authorized to overhaul the fuel selectors. Webco is one of them.

[David Rounds]

Thanks gary...I did search the forum but didn't come across that one...it does lend some insight.

Thanks Kristin...I figured as much but never hurts to ask.

David