What are my options for my fuel sump drain valves? Part numbers? Repairs? What o-rings do they use? Can they be fixed, or are they disposable parts? Mine are leaky (leaking), though they sometimes stop if I fiddle with them. I can rotate one of the valves freely; the other rotates only if I open it.
Editor:
The required o-rings can differ between valves. Usually it is an MS29513-010 inner ring and an MS29513-020 outer ring for the flush valves; and an MS29513-011 inner ring and an MS29513-018 outer ring for the post-type valves . The parts book is wrong (calls for a dash seventeen base ring on all valves); incorrect per Beech Tech Support, who state it is a dash twenty. The -20 will not work on the post-style valves; it is too large. Some people have reported needing a dash nineteen outer ring. That size is too large for the post-style valves.
The upper cross pin has been destroyed, on the drain that turns freely; it probably also will not lock open. RAPID has them in stock (PN 967B1A) for $155.82. You have two other options for new fuel drain valves.
One is the Beech flush drain valve PN 971D1 for $107.63. RAPID is out of stock in Salina and Dallas, but shows some in their WIN network. That might mean a somewhat higher shipping cost, if they are outside the USA. They are overdue a new shipment in their USA stocking locations. Usually the new shipments create a higher list price.
The other is the Saf-Air F75 flush drain valve, sold by Aircraft Spruce for $50. It is TSO’d “standard hardware”, and is cross-referenced to the 971D1 Beech flush valve, so it can be used to replace both the protruding and flush-type Beech valves. Of course, none of the flush valves can be locked open. With those the easiest way to drain a tank is to just remove the valve. You can quickly screw in a SAE 3/4-16 threaded fitting with a hose on it, to reduce spillage, if necessary. I just use a very large metal funnel (grounded/bonded). The only potential “catch” with the F75 is its full-diameter, full-length threaded barrel. On some planes it interferes with the B-nut on the fuel pickup in the tank. If you are handy with tools, that’s not really a big issue. You can use a Dremel (or whatever) to just file off the upper threads far enough to clear the fitting. The tank engagement occurs with the bottom four or five threads, so removing the upper threads has no effect on the function. You can’t go any deeper than the bottom of the thread grooves, though, so that you don’t weaken the valve body that holds the spring and snap ring.
Some remaining options for used valves:
1. You can search the salvage yards for valves; but make sure one is in good shape before buying it. Most of them are as bad off as yours, on salvage planes.
2. You can fly off fuel and drain your tanks, remove your valves, and send them to me for repair. I’ll charge $25/hour (retiree shop rate), and it should take between two and four hours total time to do both valves.
3. You can wait until I finish writing the valve repair document that I am working on, get the o-rings from me (or whomever), and try to fix them yourself. That assumes that you can properly do the necessary disassembly, polishing, and reassembly; and that your A&P will supervise and approve. I am hoping to have the doc finished for the 4th issue of BAC Talk, the BAC Quarterly Newsletter (not the upcoming third issue due out in early November 2005).
If you have a leaking base o-ring, it would be pretty silly to remove the valve to replace that ring, and not rebuild the valve while it is out. Keep in mind that some of the planes have “captured nuts” in the tanks, while others have free-turning nuts. Sometimes you can get lucky with the free nuts. You can get a thread started, and gently put pulling tension on the valve while you screw it in. If the tension enables the nut to keep still, while the valve screws in and is being tightened, you are home free. Otherwise you will have to remove the inside access panel beneath the doors (behind the upholstery panel), in order to get a wrench on the nut.