Fuel Caps

How to keep the Cessna 170 flying and airworthy.

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j3pup
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Fuel Caps

Post by j3pup »

I would like to buy some new fuel caps, just because mine are so old. Is there anywhere to find a decent price on these, at first glance the prices are ridiculous.
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blueldr
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Re: Fuel Caps

Post by blueldr »

How in hell do you wear a gas cap out? If the gas cap is on a C-170, the whole shebang is old!
BL
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GAHorn
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Re: Fuel Caps

Post by GAHorn »

Hill Aircraft: C156003-0101 CAP FUEL
(List Price: $ 45.90) Stock Available $ 39.02 (EA

800-998-7832 or www.cessnaparts.com

(Now that you know what they cost...perhaps yours ain't in such bad shape?) :twisted:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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Bruce Fenstermacher
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Re: Fuel Caps

Post by Bruce Fenstermacher »

Funny you mention old fuel caps. My friend Leroy and new partner and I were just rumageing through his 40 year collection of airplane stuff looking for a NOS master switch which we eventually found. Anyway lots of this stuff came from the collection of another deceast mutual friend of ours who collected even longer.

Well one of the boxes contained about 15 fuel caps. There had to be a fuel cap or two from every plane these guys ever owned. And there was probably a John Deer one in there as well. Know if a fuel cap is replaced chances are it's because there is something wrong with it or why replace it. So why keep it.

Of course we didn't through out the collection either. Heck you never know when your going to need a 60 year old fuel cap in the wrong color and questionable mechanical shape. :lol:
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ron74887
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Re: Fuel Caps

Post by ron74887 »

j3pup, aircraft spruce vented original style--- search fuel caps

FC3487-2 FC3487-2 VENTED FUEL CAP #2 $10.60

I installed these on my plane with the AI approval. they are vented. Ron
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hilltop170
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Re: Fuel Caps

Post by hilltop170 »

j3pup wrote:I would like to buy some new fuel caps, just because mine are so old. Is there anywhere to find a decent price on these, at first glance the prices are ridiculous.
Hey j3pup-
I have the new style red vented Cessna caps that came off my 170 when it was restored. They are still serviceable but faded. You or anyone else can have them if you pay the shipping from Alaska and can wait until the middle of May for them.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
j3pup
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Re: Fuel Caps

Post by j3pup »

Thanks guys, my airplane sat for a number of years and only has the vented cap on the right wing. I understand the importance of the right cap venting and just wanted to make sure it still does. Additionally the rubber on them has made it very difficult to remove the caps. I tried soaking the rubber in brake fluid, but it didn't help much, I figured they are just fuel caps, how expensive can they be. haha Going to look into these 10$ ones, and probably just get two vented caps and vent both tanks.
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Bruce Fenstermacher
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Re: Fuel Caps

Post by Bruce Fenstermacher »

Before spending even $10 get new gaskets for the legal (presumably) one you have now. Then figure a way to test the vent. Shouldn't be to hard. Blow air through the vent hole maybe?

BTW I'd expect soaking gaskets in brake fluid would swell them and make the cap hard to remove. Or perhaps that was your intention to swell them because they currently don't seal.
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GAHorn
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Re: Fuel Caps

Post by GAHorn »

ron74887 wrote:j3pup, aircraft spruce vented original style--- search fuel caps

FC3487-2 FC3487-2 VENTED FUEL CAP #2 $10.60

I installed these on my plane with the AI approval. they are vented. Ron
Here's a link to the caps Ron is suggesting (more on that later):
http://www.aircraftspruce.com/catalog/a ... elcaps.php
You can also buy gaskets for your present caps (the ones in the link fit) for only $2.

Now,...this is only MY opinion. (It's worth about what Ron's IA's opinion is.)

Just because some AP/IA says something is "OK" ...does not necessarily mean it is in accordance with what FAA or Cessna says. Unless the supplier is able to provide proof of FAA-PMA or other approval basis, those caps are suitable for experimental aircraft only.

While the "generic" caps in the "link" will probably work just fine, and as they are just about as simple as can be.... they are NOT approved caps for our airplanes. The genuine Cessna caps are what should be used, in my opinion.
While the generic caps are simple-enough, and while they will likely work forever, they do not have a vent check-valve like the genuine Cessna caps have. They will therefore, allow rain and water to more easily enter the fuel system. (Water will probably get in there anyway with the condition of most of our genuine caps gaskets and "moats", but the generic caps are simply metal caps with a hole drilled in them, and are most suitable for a tractor or other vehicle with a "door" or hood to protect that cap.)

I'm not criticizing anyone's choice to use the generic caps. I've even provided them to a "certain goofy" we all know who visits these forums, who put them on his wife's C-150, and I admit they look and work just fine on that hangared aircraft. They have not caused a single problem on that hangared aircraft or it's empty fuel system as it has sat there for 4 years in the hangar.
Are they legal? Yes. As long as that airplane sits in that hangar.
But until someone gets an STC or PMA or other approval for installation, that airplane is not likely really airworthy with those caps. Neither is a certain airplane in Looeasyana that a certain alligator tour-guide has, despite what his IA says. :twisted: (unless the "rest" of the story involves some field approval, or similar, etc.)

Painting them red would be nice. :P
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
j3pup
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Re: Fuel Caps

Post by j3pup »

Alright buying new seals, thanks all.
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Roesbery
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Re: Fuel Caps

Post by Roesbery »

I put some Fuel lube on my gas cap gaskets over a year ago and they still work great. Do not stick like they used to, and can get them on and off by hand without a cheater. Something to consider if your caps are tight and hard to get on and off.
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170C
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Re: Fuel Caps

Post by 170C »

Years ago I was having fuel leak problems (recently corrected via VP Jim's procedure--I hope--haven't flown it yet to test it) and had replaced the gaskets, etc with no help with the leaks when the tanks were full. Mentioned this to C-170 member Goody Goodrich & he told me I could get vented caps at some of the local auto supply stores, as he had, and they would work as good as the high dollar ones, albeit illegal. I told them I needed a couple of caps for a 53 Ford pickup and for about $6.00 each got ones that were either polished metal or stainless. They were vented and worked as well as any except they didn't have the hole drilled for the safety chain (could have been drilled I think) and were of course not legal. Ran them for years with no problems until 2009 when I went ahead & purchased the nice new red ones. Still had leaks, but hoping that was the tank adapter gaskets, not the filler neck itself or the caps. Will know later this week.
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Robert Eilers
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Re: Fuel Caps

Post by Robert Eilers »

Fuel Lube - great idea. I have been using WD40 or LPS-1 on my "Red" cap when it starts to get hard to tighten or loosen. I currently have one standra cap on the left tank and one "red" vent cap on the right tank. I tried two vented "Red" caps and found that with the two "Red" caps the goose neck vent seemed to spit fuel (when full) more than with just one "Red" cap :? .
"You have to learn how to fall before you learn how to fly"
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GAHorn
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Re: Fuel Caps

Post by GAHorn »

If you purchase new caps from Cessna...they will be vented caps. NO unvented caps are sold by them for this airplane.
I have two vented caps and have no problems with the gooseneck spitting fuel. But there is a brown stain that develops after many months streaming back from the caps, probably from dried cap gaskets...I should probably replace them.

The red plastic does eventually become "chalky" and will clean up with mineral spirits, etc. to return to a bright red. And MEK cleans up the dried fuel stains on the top of the wing nicely. Acetone would likely do as well.

The Fuel Lube idea is a great one! (and I have a whole can of the stuff looking for something to which it may be applied!) :lol: DC-4 should also work for life-limited periods...it's much less expensive.

NOTE: If you have a gooseneck which seems to spit fuel regularly, take a close look to see if it has the hole drilled in it's aft curve from the obsolete Service News Letter (SNL). Those should have been re-sealed to delete that SNL.
Also inspect for the "check ball" installation, which involves a cotter-pin thru the gooseneck.....another SNL which should have been cancelled and the vent returned to original.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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170C
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Re: Fuel Caps

Post by 170C »

This brings up a question-------during my fuel tank project I found out that my gooseneck tank vent (on upper side of left tank on 56 C-172) does not have a check valve in it nor is there one anywhere else in the vent system. All that is in the gooseneck is the cotterkey which presumably is to discourage critters from crawling down inside. I removed what appeared to be a wasp type insect that the cotterkey had caught. I don't see any check valve in the parts catalogue so am assuming there isn't supposed to be one on this particular model Cessna. Might be that since the gooseneck vent tube is on the upper surface & extends about 4 inches above the wing surface that Cessna determined it's not needed. Anyone with different knowledge let me know.
As an aside, my 56 C-172 (conv gear) has two 21 gallon tanks. When I completed my fuel tank project and had two completely empty tanks I had the FBO come down and fill both tanks so I could see what they would actually hold in the 3 point configuration. 19.6 gallons on the left (same as I had previously determined two previous times, but wasn't certain the plane was level) and 19.4 gallons on the right. Guess I can't flight plan based on 42 gallons :roll: Will have to use about 39 less a minor amount of unusable. When I ran the left tank dry I sumped the remaining fuel out and then pulled the sump drain. I filled one of the drinking water bottles 3/4 full. Must have been just over a pint. Yep, you can use about all of it and no, there wasn't any fuel left in the tank after preforming this. I guess the wing dihedral prevents a minor amount in the outboard end of the tank and in the tail low position there is likely a minor amount of tank space at the upper/forward area that can't hold fuel due to the filler neck being aft of that area. I am guessing B model 170's experience this as well :?:
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