rebuild fuel selector valve
 

looks like I am going to need a fuel selector valve rebuilt. who does these for 337? (I haven't had chance to call McFarlane yet; I see they rebuild others.)

If it’s only leaking then it’s easy to replace the cork seal. But good luck getting that part. However, getting a sheet of cork and making the gasket is cheap and easy.

It's not providing a positive cut off of fuel flow. Wish it was easy as just needing cork gasket. Internals will need to be serviced. Are there any flexible rubber/plastic life limited internal parts? Is there a service kit?

I just went through this. The issue of leaking past the valve is from the little balls not sealing on the seats. The selector valve has a small well in it that can collect water. I think this contributes to the problem. The ball is held against the seat with a spring that is likely rusted. There will also be some rust on the seat that is causing your leak-past. You can remove the valve and see the ball/seat assembly. Don't remove the little clips that hold in the spring. They seem to be impossible to find. If a replacement clip/retainer was available this project would be pretty easy. I was only able to find one guy that was willing to look at them. He wanted a fortune and was a bit on the grumpy side.

I had one guy that thought removing the spring and ball and re-cutting the seat was the answer. I sent him one of my valves. It just sat on his desk for two months. On close inspection the seat was not pitted it appears to have surface rust that would likely clean up.

I think an ultrasonic cleaner would be a good start.

I found a pair of used valves that were not leaking.

Dave

Has anyone used B & S in Wichita lately?

I have been studying the valve drawings and come to the same conclusion myself about either corrosion (most likely) or some grit stuck in the ball/seat area. Also, been doing some research and B&S in Wichita is on my call list.

I have one of the old valves on the shelf. I'll take some pictures so you can plan your attack.

Dave

sounds great. surely there must be a matching internal c clip somewhere (I've been shopping internal c clip assortments-a kit with various assorted sizes very affordable) or if part is serviceable, clean things up and reuse.

There is! It's this little self-destructing thing that springs itself out of position once removed.

Dave

I dug out the old fuel selector valve. I have no recollection of how to attach a picture so I'm attaching several pictures. My computer has a .020" diameter thumbnail of the picture which is useless. Unfortunately I don't know how to add any descriptions to the pictures.

Here is a picture of the o-ring that sits on the shaft of the selector lever. This could be a source of leakage.

oh my goodness. that internal clip that holds the spring does look like it will be a problem. I wonder if an internal c-clip would work in it's place.

I will measure the thickness of it tomorrow. I don't have the right caliper to measure the inside groove diameter where it seats. One thing I would encourage is to take pictures and mark where the tubes go before you remove it.

Dave

additional info?
 

I was wondering if there was any follow up to this posting. I got to fly my skymaster for the very first time today.....and what a machine these things are!!!! What I found out was that when we were flying on the main tanks, the front engine would also pull fuel from the aux tank. 2.5 hours of flying time used 8 gallons out of the left aux tank. I moved the selector valve around a bunch of times to see if there was something stuck in it that could get worked out, but used about the same out of the aux tank on the next 2.5 hour flight. I am thinking the balls and seats have corrosion on them as was shown in the pictures in the post. I didn't want to have my mechanic rip it apart until he was certain he could replace those clips if one were to be broken or lost in the process.

Also, in the post below there is mention of B and S in Wichita. Did you ever reach out to them regarding rebuilding the valve? Just trying to wrap my head around all the options.

Thanks much guys!!!

Rigging
 

Tom,
I am not saying that it could not be some internal corrosion or problem in the valve, but if you have not verified, just double check the rigging of the valve. One small panel on at the wing root and a mirror, and you can verify that the valve is in the detents and rigged properly.
Jeff

Ended up leaving the valve alone. (We got sidelined with more critical issue of flap-trim interconnect cable seizing in its sheath and restricting trim control.) It's on a future project list when can stand risk of long term disabling the valve. But have been concerned about what you experienced. Likewise agree about checking the rigging.

Thanks guys! I will check the rigging and go from there - that is a good idea o verify the easy stuff and go from there. Thanks again!

rebuild fuel selector valve
 

wslade2.
FYI, you CANNOT just replace the original clips with a C clip from a assortment of clips. That would be illegal. I'm not trying to be a know it all but as an A&P I know there are rules in the FARs that prohibit this kind of modifications. If the original clips are not serviceable and hard to come by you may have to buy a serviceable selector valve and replace the whole valve?? Has anyone tried contacting AIRBORNE the original valve manufacturer, for the clips?
Just a thought.
Regards, BILLS

McFarlane
 

Has anyone used McFarlane to rebuild their fuel valves? I spoke with Dave 2 days ago and he told me they can rebuild them now. He said it's mostly labor, but they do fabricate a few pieces. He mentioned somewhere in the $600 range.

We're having some issues and may need a rebuild also.

That is super duper news! McFarlane was on my list.
Tried to call Airborne for parts. They don't exist as they did before. They have been absorbed by parker hannifin.
(check this link: https://semspub.epa.gov/work/05/465914.pdf)
Called Parker Hannifin, pretty big outfit and have not gotten a call back from them. (out due to coronavirus?)
Did call B&S and they think they have one gasket on the shelf but did not want to sell it in case they need it. They said their suppliers have stopped. Then got call from someone else there who wanted me to call yet another person there to see if they have capability to service it. But have not gotten a call back yet.
They also directed me to Ross Aviation parts. Ross reports the valve is superceeded by a 1H12-3 obtainable at a price of $14,000 (yes fourteen thousand). Yingling also has it for $14K and change with a $3000 core charge. To dive deeper in parts, would need a repair manual for the valve listing part numbers for springs/gasket/retaining rings.
Called Quality Aircraft Accessories and they confirmed (again) they do not service this valve.
Called Cox Airparts and they said they were getting out of the fuel valve business.
But the good news is, called Powerpacks Plus. They will repair it. They won't overhaul it, though, and you won't get a part back with paperwork/certificates. But it can be worked on.
I couldn't find anyone to supply parts, retaining rings, springs, gasket.

FYI
Dave owns a Skymaster