Dukes fuel pump overhaul

FORANE

FORANE

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My dukes fuel boost pump in the lancair is failing. It occasionally won't start, it doesn't get up to the pressure it previously would get to, it's speed varies as it struggles to run.
Based on reviews here and elsewhere I just sent it to aeromotors. They said send it in a box with a check for $550 and include a return shipping label.

Is permatex 80019 acceptable for use as a thread sealant on the pipe threads in this application?

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FORANE said:
Is permatex 80019 acceptable for use as a thread sealant on the pipe threads in this application?
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If talking about the NPT fittings application yes it can be used. But I prefer Fuel lube/EZ Turn instead. Loctite 567 is also an option for NPT fittings and I believe is the one Cessna calls for on fuel fittings. AN flare fittings should use no sealant.
 
Why not use 80633 permatex pipe thread sealant?
80019 is a gasket sealant that might get hard and crack over time.
IMO any pipe dope would work.
But not teflon tape or gasket sealant.
 
Gary Ward said:
Why not use 80633 permatex pipe thread sealant?
80019 is a gasket sealant that might get hard and crack over time.
IMO any pipe dope would work.
But not teflon tape or gasket sealant.
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I just shipped the pump in for overhaul yesterday. At this point I'm researching what to use. I know Teflon tape is not to be used. I've read about ez turn / fuel lube and locktite 567. I've read that the sealant used should be used sparingly and only applied to the male threads.

I'm considering permatex 80019 because I already have some, it's manufacturer documents say it may be used on threaded fittings, it's fuel resistant, and non hardening. Not sure I want to use locktite 567 because it's hardening and non soluble in fuel; what happens when a blob of it gets in the fuel line? Not sure I want to use fuel lube ez turn also because it is completely non soluble in fuel. I'm open to getting feedback from those who've been there before me though. With an EAB, we're free to use different products and don't have a policy manual to follow, hence the research.
 
I’d swear that’s the same pump on my Lancair and those are straight threads with an oring on mine. No sealant.
Aeromotors sent new orings.
 
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The nut in the yellow circle is not in safety. Its bolt is too short and the nylock isn't holding to it. The one on the other side isn't much better. Standard practice is one to three threads past the nut's top.

That port is the green circle is the drain for the backside of the seal between the pump and motor. There will be another port opposite it, under the pump. That lower one should have a fitting and a bit of tubing to carry fuel overboard under the airplane, to protect the pump and keep fuel out of the cabin. That top port should be plugged.
 
Let'sgoflying! said:
I’d swear that’s the same pump on my Lancair and those are straight threads with an oring on mine. No sealant.
Aeromotors sent new orings.
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I'll look when I get it back but the npt threaded fitting on the right side of the pic posted upthread has some sealant on it. Also this filter has npt threads that will require some sort of sealant.
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Dan Thomas said:
View attachment 147124

The nut in the yellow circle is not in safety. Its bolt is too short and the nylock isn't holding to it. The one on the other side isn't much better. Standard practice is one to three threads past the nut's top.

That port is the green circle is the drain for the backside of the seal between the pump and motor. There will be another port opposite it, under the pump. That lower one should have a fitting and a bit of tubing to carry fuel overboard under the airplane, to protect the pump and keep fuel out of the cabin. That top port should be plugged.
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The yellow circled nut I had backed out a moment before taking the pic for pump removal purposes. The green circle, I was unaware of needing a plug, thank you. The opposite side appeared to have a sealant of some sort; there was no drain present.
 
Dan Thomas said:
View attachment 147124

The nut in the yellow circle is not in safety. Its bolt is too short and the nylock isn't holding to it. The one on the other side isn't much better. Standard practice is one to three threads past the nut's top.

That port is the green circle is the drain for the backside of the seal between the pump and motor. There will be another port opposite it, under the pump. That lower one should have a fitting and a bit of tubing to carry fuel overboard under the airplane, to protect the pump and keep fuel out of the cabin. That top port should be plugged.
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Exactly. The overhauled pump should come with a new anodized plug to be installed in the upper (non drain) side.
 
Let'sgoflying! said:
I’d swear that’s the same pump on my Lancair and those are straight threads with an oring on mine. No sealant.
Aeromotors sent new orings.
Click to expand...
Yep. I just installed one. It had o’rings. IPC shows them as well. Of course the overhauled pump came with the wrong O’rings for my application but that was easy enough to order.
I use a lot of Fuel Lube/EZ-Turn but haven’t applied it to fittings with O’rings. Tempted but not certain of it’s compatibility with O’rings.
 
Received the pump back from overhaul today. That is a very quick turnaround time considering it was ground shipping both ways. The pump looks great. It came with the 2 o-rings necessary for installation fittings which was very nice as I would not know what o-ring was needed and would have to wait for them once I got them ordered. So far I am impressed with Aeromotors.
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Looks good. The place I used chopped my electrical connector off and trashed it.They usually send 1 new plug to be installed on the topside drain. If not just use the old one.
 
Jdm said:
Looks good. The place I used chopped my electrical connector off and trashed it.They usually send 1 new plug to be installed on the topside drain. If not just use the old one.
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The old plug for the topside drain was missing. The bottom drain was not connected to anything.
 
Install an aluminum plug fitting in the top. Put a hose fitting on the lower. Run the hose out the airframe through a grommet or gang drain. Here’s a couple pics of a typical setup.
 

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Jdm said:
Install an aluminum plug fitting in the top. Put a hose fitting on the lower. Run the hose out the airframe through a grommet or gang drain. Here’s a couple pics of a typical setup.
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I started looking at doing this and noticed they did include a plug. It was installed in the bottom drain hole. I moved it to the top and will look for a suitable hose fitting. Looks like it is 5/16-24.
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Here’s a couple part numbers that might help you compare or locate:

Elbow, Pump Drain
2140-53 (old p/n)
35-924291-1 (current)

These are Textron numbers for the same Dukes pump
 
Dan Thomas said:
It's a 1/8"-27 NPT pipe thread. Don't wreck the threads by sticking anything else in there.
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Dan, I looked online at parts diagrams but failed to find information on this. For my education, did you know that by experience or is there a way for commons like me to find this data.
Thanks again...
 
You might want to check your output pressure on the overhauled pump. According to a current thread on another maint forum the company you used has had some
issues. I have no experience with them myself. Here’s a copy and paste of what’s being discussed:

“If you purchased your pump from Aeromo-tors, this may turn into a lesson learned.”

“Yep. It was Aeromotors. I'll give them a call.”

“I'm only getting 7 psi fuel pressure when I turn it on on the ground. Expensive lesson learned. Interesting they can keep their FAA certification.”
 
Jdm said:
You might want to check your output pressure on the overhauled pump. According to a current thread on another maint forum the company you used has had some
issues. I have no experience with them myself. Here’s a copy and paste of what’s being discussed:

“If you purchased your pump from Aeromo-tors, this may turn into a lesson learned.”

“Yep. It was Aeromotors. I'll give them a call.”

“I'm only getting 7 psi fuel pressure when I turn it on on the ground. Expensive lesson learned. Interesting they can keep their FAA certification.”
Click to expand...
I flew it yesterday morning. It performed flawlessly. It runs quiet, pressure comes up quickly into the green (26 psi), no leaks... When the engine driven pump is running and the Dukes pump is running the pressure doesn't go over-pressure. When the air was being purged from the line with the engine driven pump alone the pressure would dip but adding the Dukes pump quickly brought the pressure right back up into the green. I'm very happy with it.
 
Jdm said:
You might want to check your output pressure on the overhauled pump. According to a current thread on another maint forum the company you used has had some
issues. I have no experience with them myself. Here’s a copy and paste of what’s being discussed:

“If you purchased your pump from Aeromo-tors, this may turn into a lesson learned.”

“Yep. It was Aeromotors. I'll give them a call.”

“I'm only getting 7 psi fuel pressure when I turn it on on the ground. Expensive lesson learned. Interesting they can keep their FAA certification.”
Click to expand...
I've read reports stating that, unlike my pump, the power wires must be connected with proper polarity. If connected the wrong way the pump will run in reverse. I've read reports that the pump came from overhaul with a note on the wires (like mine had) stating that polarity didn't matter even on a pump where it did matter. Perhaps that is the issue with the other guy. I believe I read that report on a pump sourced from aircraft spruce.

Edited to add: yes, it was ACS where I read that. Read the reviews on the link below.
www.aircraftspruce.com

Rapco Dukes Overhauled Fuel Pumps | Aircraft Spruce ®

Rapco Dukes Overhauled Fuel Pumps RAPCO produces FAA approved quality new and overhauled electric auxiliary fuel pump.
www.aircraftspruce.com www.aircraftspruce.com
 
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Yeah, I recently had a Dukes overall shop manager tell me the same, that polarity doesn’t matter. However, the wires are identified as red/pos and black/neg. He’s probably right from bench standpoint. As a line mechanic there’s no way I’m going to intentionally disregard what the WDM clearly shows.
I think the problem mentioned on the other forum was due to low output. The guy checked his isolated elec pump output readings. Isolated meaning without the engine and EDP operating. They were less than half the gpm required.
His elec pump is only used for engine start and in flight emergency due to an inop EDP. Some of the tech guys speculated that he didn’t have adequate output to safely operate in this type of emergency.
 
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