Imperial Primer leaking

Fuel tanks, systems and parts
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flyingfool
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Imperial Primer leaking

Post by flyingfool »

On my Chief I have a primer that is leaking. This primer is made by Imperial. It locks by threading it in. So it is not the typical Lunkin (spelling???) primer which has the post and slot method of locking. I've never seen the kind of primer before I have in any other plane.

Anyhow this imperial primer is shaped like the letter "T". The primer pump is the long stem or trunk part of the "T" shape, while the fuel into the primer and out of the primer is at the top of the "T" shape.

The leak only seems to leak when the primer is stroked with full fuel. The leak seems to be at the junction of the stem and the top of the "T". But if fuel comes out, then certainly it is conceivable that air can come in.

Does anyone know how this primer is made? It may be that this T shape is made by a simple threaded connection. If so then maybe some thread seal would work to stop the leak. If so what type of sealant would I use? I understand that teflon tape is a no-no.

Is anyone familiar with this imperial type primer?

Do I have to completely drain the main fuel tank in order to work on the primer? Or can you just unscrew the compression nut, let the fuel run out until you can stick a toothpick or some other plug in the small copper primer line??
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james gevay
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Re: Imperial Primer leaking

Post by james gevay »

Here's a picture of the primer you have. This used to be in my Champ years ago and it leaked too, I think I tried new o-rings but that didn't work well and I replaced it with a different kind. Back then I didn't know as much as I know now about these planes and maybe I could fix it today if I tried.
I believe the two parts of the brass "T" are soldered together, and the bullet shaped plunger on the end of the shaft is threaded on to the shaft and a piece of safety wire keeps it from coming off.
Maybe you can see exactly where yours is leaking and with parts laid out here come up with a plan to fix it.

What I've been using on fuel and oil threaded fittings is Fuel Lube, it comes in a 1lb can and it'll last you a life time. It looks like real thick honey and I spread a little on the threads, I think it's impervious to fuel and oil.
Don't use that automotive silicone junk.

Image
flyingfool
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Re: Imperial Primer leaking

Post by flyingfool »

Thanks. That's it all right!

I don't recall when I had it apart a couple years back the bullet shaped end. recall, mine is flat and the pump seal was actually a piece of leather. But maybe it was pointed but it definitely only had a leather seal. No "o"-rings to be found.

I was dismayed a bit at the leather as I didn't think it got good suction or sealed well. So I put some e-z turn fuel valve lube on my fingers (sticky stuff!) and patted the leather to get a coating but not too think or any excess globs on the leather hoping that would help the seal. It didn't really seem to work. But it did slide in and out well.

Also mine by looks appears to be aluminum rather than brass. But it too visually looked like it was soldered or brazed together T-joint. I wonder after drying completely of fuel, if I could try "sweating" the solder joint again like on copper plumbing connections?

What did you replace yours with? Was it a direct replacement or was other primer fuel line modifications needed?

Maybe it's not worth saving and just buying another primer would be the solution.

How much does a new primer cost????
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james gevay
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Re: Imperial Primer leaking

Post by james gevay »

OK, this is what I remember from when I replaced it about 20 some years ago. It may have had a leather seal somewhere, I don't know, I do know I tried to stop the leak with new O-rings and that didn't work. I replaced it with an Essex from Aircraft Spruce and Specialty, I think it may have been around $30.00.

I think we needed to put new fittings on the ends with a flare. Easy with the proper flairing tool. I don't know the part No. for the fittings, but they're for 1/8" lines, an A&P would know, or could look it up.

Here's a picture of an Essex on the left and a Koehler on the right. Both are nearly identical, the casting is slightly longer on the two ends of the Essex and the end of the plunger is different on the end, a ball as opposed to the point. They even have the same part No. on them.


Image

Now on to the bad news, sit down and hang on, the price for new at AS&S is $248.00, thats no misprint.
Don't ask me why it's such a crazy price, I don't know. There's a cheaper one for $122.00, I don't know know diference between the two.

Now, I see two of them on E-bay right now, one ends in about 1 1/2 hours. They come up on E-bay from time to time. Sometimes they go for about $100.00 there.

I just happened to Google Essex primer and found some info on them from other small plane forums, there's some pictures and a talk about possible parts from Essex themselves.

http://www.shortwingpipers.org/forum/sh ... ght=Primer

I can't sell you my spare Koehler as the threads are screwed up on one of the ends.
Hope this helps, good luck
MikeB
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Re: Imperial Primer leaking

Post by MikeB »

I think the one on my L16 is from a Cessna 150 if that's any help.

Mike
flyingfool
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Re: Imperial Primer leaking

Post by flyingfool »

I also looked up the price at ACS, and I'll be damned if I'll pay $250 for what amounts to a glorified hypodermic plunger.

I will remove and try to fix the one I have. I have to believe that it is repairable. If not I'll find a used primer somewhere. It would seem like they would be almost a dime a dozen. I have to believe that there is an old primer laying around the parts bin of an A&P locally or by a fellow member here. I'm willing to pay a reasonable price. But $250 is no where near the universe of fair or reasonable price! I think with the new FAA- AC that I can install any primer that has been aviation approved. There has I've got to believe to be a million Cessna and Piper primers laying around just waiting to be put back into service.
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james gevay
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Re: Imperial Primer leaking

Post by james gevay »

I watch for certain parts on E-bay and I happen to see the price of primers go way up in the last so many years, don't ask me why.
The Essex last night on e-bay went for $45.00 + shipping, a really good price.
I would watch E-bay or salvage yards, or maybe your A&P knows where one is lying around on a shelf. Your right, there has to lots around from Cessnas and Pipers.
MikeB
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Re: Imperial Primer leaking

Post by MikeB »

Regarding Aircraft Spruce you're right, the parts are a rip off. Here's another good example: there was a company (name escapes me) that used to sell Good Year brake pads for less than $10 each. ACS bought them out and now the price is $66.75 each (Yah...I know you can make them but it's the point...... :evil: ). The little spring clips for GY brakes are $160 each and they used to be overpriced at $60. I realize there's a certain aount of liability in aircraft parts but not much different than the 18 wheelers I used to work on in my earlier life. I mean brakes are brakes. Here's another example: I was trying to get hangar insuance and the companies were dragging their feet because it was 'on an airport' (like where else would it be??).

Mike
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