8KCAB Fuel shutoff valve

[Big Ed]

Can the fuel shutoff valve be repaired, or should it be replaced? Anyone have a part number?

Mine is creaky and hard to turn. No exterior leaks. However, I suspect it might be leaking internally and not fully shutting off. If I close the valve and drain the gascolator, a few minutes later there will be fuel in the gascolator again.

 

[Big Ed]

Here is a crop of the valve. I'll get a better close-up pic next time I am at the airfield.

Another question: is there any way to shut off fuel flow to this point without draining the tanks?

 

[Bartman]

It is super easy to take apart to clean and lube but if fuel is leaking past the valve I'm going to guess it can't be fixed. It's just a tapered plug so if the tapered female seat is worn or the plug is worn then it's probably a goner.

here's a few pics from disassembly

Bellanca-era Imperial Fuel On/Off Valve

Took a few pics of the valve that came with my project in anticipation of cleaning and reinstalling it. Later found out it didn't fit the bracket that was on the frame. :( Figured the pics might help someone planning to remove and rebuilt theirs. The first four were as it was being...

champcitabriadecathlonforums.com

they can be found on ebay and I'm pretty sure there's only a gasket or two sealing where the valve shaft exits the packing nut (not really a packing nut but what else to call it???)

 

[Big Ed]

It is super easy to take apart to clean and lube but if fuel is leaking past the valve I'm going to guess it can't be fixed. It's just a tapered plug so if the tapered female seat is worn or the plug is worn then it's probably a goner.

here's a few pics from disassembly

Bellanca-era Imperial Fuel On/Off Valve

Took a few pics of the valve that came with my project in anticipation of cleaning and reinstalling it. Later found out it didn't fit the bracket that was on the frame. :( Figured the pics might help someone planning to remove and rebuilt theirs. The first four were as it was being...

champcitabriadecathlonforums.com

they can be found on ebay and I'm pretty sure there's only a gasket or two sealing where the valve shaft exits the packing nut (not really a packing nut but what else to call it???)

Looks pretty simple. I'll open it up and take a look. I think I have to drain the fuel first though.

 

[Bartman]

just thinking about this, the simple nature of the plug leads me to believe a little leakage past the valve probably isn't unheard of. you'll know better once you look at the condition of the valve

 

[Big Ed]

Some fuel lube ought to seal it up. I never use the darn thing anyways, except for when servicing the fuel system components forward of the firewall.

 

[Joe]

It should have about a -11 o-ring sealing the shaft. Chucking the plug into a drill and wrapping it with 600 grit paper you can polish the bore then turn the paper around and polish the plug. Careful not to remove too much material. Unless it is really bad fuel lube will reseal it.

 

[Big Ed]

Turns out mine is not leaking after all. Some fuel lube should smooth up the rotation.

 

[Bartman]

Turns out mine is not leaking after all. Some fuel lube should smooth up the rotation.
View attachment 5244

Ed,

Before you do any more disassembly would you mind photo mapping the area ahead of the instrument panel and especially the firewall forward? Take as many photos as you want from all angles and post them in a new thread for us slugs that are already rebuilding. You'll also appreciate it yourself when it comes time to start reattaching things.

Or you can just truck that baby up to my hangar and leave it there while I finish my project so I have a reference. Or you can just post photos.

edit: I see you've removed the firewall already, oh well, whatever you can still do would be appreciated. I should have thought to ask earlier.

Thanks!
Bart

 

[Big Ed]

I've taken a zillion photos. Will post when I get some time.

Currently pondering whether to make mods to the FW layout, the big one being moving the gascolator. Leaning away from it right now, but I will price first.

 

[Big Ed]

Took it off and broke it down. Looks simple. Not leaking so I am not going to fool with lapping it. Had lots of died gunk in there; probably fuel contaminants that settled in the groove at the bottom of the cone. Soaking it in acetone and hitting the threads with a brass bristle brush got it nice and clean.
Has a bit of discoloration on the shaft. I might try to polish that a bit.
Looks like it needs a rubber shaft seal and a copper gasket. Is the shaft seal an o-ring or something special? Anyone have the MS number for the parts? A dab of fuel lube and it should be good for another 20 years.
Next post will address upgrade decision.

 

[Big Ed]

ACA sells an upgrade kit. It is featured on their website as one of the most popular kits. The old shutoff valve is no longer made, so they had no choice but to do a redesign. The new valve requires a new bracket (pictured).

Repair parts are no longer available. AFAIK the overhaul parts are common MS. But if you break the shaft, or if the cone leaks and can't be fixed by lapping, your only recourse would be to buy a salvage valve somewhere or do the upgrade.

ACA recommends doing the upgrade preemptively as part of a frame resto. In Jerry Melhalf Jr's words, "if the valve breaks right after you finish the restore, that is going to piss you off."

The upgrade entails not just the bracket and valve, but also the new style gascolator relocated to the edge of the firewall, where it can be sumped from a hole in the lower cowl. Clearly that is an operational advantage, be especially since sumping onto the ramp is an EPA violation that might get you and your airfield fined

That is also probably $1K in parts. And while you are at it, you might as well spend another $1K on a shiny new SS firewall with the holes in the right places.

All that makes sense if you are going for a full "brought up to current specs" restoration. BUT ... IMO is overkill if your goal is a flying bird again on a reasonable budget.

After seeing the valve, to me this is a clear example of the value of preventative maintenance. If you take that valve apart every few years and lube it, it should easily last a lifetime. Let it get dry and try to force it, and you may well break the shaft and "piss yourself off" as JMJ put it.

After looking at the bracket, IMO this would not be a difficult upgrade later if needed, even with the cover and engine on. The new bracket appears to have the same location and geometry as the old bracket, and differs only in the cutout and bolt pattern. Access would be reasonably easy with the boot cowl pulled back and floorboard out.

 

[Joe]

The seal is an O-ring. I will look Monday and see if I wrote down the number. I am thinking it is MS29513-11

 

[Big Ed]

The seal is an O-ring. I will look Monday and see if I wrote down the number. I am thinking it is MS29513-11

Cool! Any chance you have the copper (brass?) gasket specs too?

 

[Joe]

I just polished it copper gasket and reused it.

 

[Hiperbiper]

Brass crush washer is an AN 900- xx part.
Just measure the id of the old one.
Chris

 

[FlyAZ123]

The washer size looks like an AN900-13 but it's not a crush washer, but a flat washer that I'm having a devil of a time finding one to fit. Would a crush washer sub for the flat one and work?

 

[bluehaze]

my fuel valve is leaking. I want to rebuild it. What parts inside the unit need to be replaced, and where can I purchase the, or do they sell a kit? Replacing is not an option right at the moment without having to move the plane a pretty good distance. Thanks This is all so helpful

 

[Bartman]

does it turn freely? If so, chances are good it just needs to be disassembled, cleaned, and reassembled with some fuel lube and a new o-ring. click the link in post #3 for photos of the parts. don't forget to empty the fuel tanks before disassembling the valve, or have an A&P do it.