Fuel Caps

[170C]

Got my new "RED" fuel caps from Spruce & put them on today. I am hoping the one on the RH side stops the leak I always get when that tank is topped off---we'll see how that works out. I have a couple of questions about these caps. First, in the piece that has the vent in the middle (the ears used to turn the cap to open or close it), there is a hole drilled (?) through each "ear" just outboard of the middle where the vent is located. What is the purpose of those two holes? Could it be for some type of adapter used to close or open the tight fitting caps? Second question --does anyone make a tool or has anyone come up with a homemade tool that will assist in opening the caps (or final closing? It takes about all of my finger/thumb power to close one of them and the other one required me to make the final 1/4 inch with the help of some pliers over a towel (to prevent marring the cap). I doubt I will be able to open that one without using the pliers or similiar to assist. My idea of the caps being properly closed is for the "ears" to line up fore & aft. What do ya think

[W.J.Langholz]

Ole poky

I just put 2 new ones on about 3 weeks ago. Pretty red ones they are. The first time I put them on I had the same problem. Did the same with the plyers and rag. In about 1 1/2 weeks they loosen up some and I could get them off with my fingers. Give it alittle time, you should be ok.

Willie

[Senior Chief]

Next time you remove the caps give the gaskets a good shot of WD-40
I do this every time fuel is added.

[Roesbery]

I haven't done it yet but was thinking some fuel lube would be the most durable on the gaskets. Been just using a leatherman tool for additional grip.

[blueldr]

Some years ago, in Fallon, NV, my airplane was being serviced with gasoline by a "mature" lady that seemed to be running the FBO. She opened and closed the fuel caps with what I considered a very clever tool. It was simply made of three very short pieces of 3/4" PVC pipe glued into a TEE with slots cut into the off leg of the tee so that it engaged the ears on the gas caps. The added leverage was ample to turn the most uncooperative caps. I subsequently stole her invention and carried one on board.

[GAHorn]

If your tabs do not align ("line up") fore/aft, you're not going to like the fix, which involves removing and re-indexing your fuel tank filler necks.

(Hint: I'll bet those non-aligned caps don't bother you so much anymore after reading that, do they?)

[170C]

I appreciate the suggestions. George, I don't want to have to modify the caps to make them line up properly with the airstream. Fortunately with the extra effort mentioned, they do line up. Sure don't need any added drag on ole pokey The ones I have been using were chrome (?), vented, smooth caps like one would find on an old Ford or Chevy pickup. Didn't have provisions for the safety chain, but didn't stick up like the new ones and the ones I used to have on before I switched to the automotive ones..Darn old fashioned ones cost about $6 a piece---with the new ones I get to help the economy by paying about $70 total including shipping, but now I can sleep at night knowing they are legal Funny thing I didn't see the correct ones in the Spruce catalogue, but they are in there by going on line. I suppose that a little DC-3 lubercant wouldn't hurt on those either. I liked the idea the lady at the FBO used. If mine don' t loosen up after a while I might have to fabricate one myself. Still don't know what those two holes in that tab/ear are for

[Bruce Fenstermacher]

I suppose that a little DC-3 lubercant wouldn't hurt on those either.

Your thinking of the wrong airplane. Your thinking of a DC-4 lubercant.

[hilltop170]

For some unknown reason, I usually seem to have some MMO around when I'm filling the tanks. I dab a little MMO on the cap gaskets and they are always easy to put on and take off.

[170C]

Well, I can't remember which airplane (DC-3 or DC-4) that I have in the green box in my hangar frig. I use it on the oil filters when I am putting the new one on the plane. I hadn't thought of the MMO. I have a bunch of it in the hangar. Yrs ago I was in a local Sam's & they had it at a super cheap (relatively speaking) price. Only thing was, you had to buy it in 4 gallon lots. Think I still have a couple of gallons sitting on a shelf out at the apt. I could coat the rubber gaskets with that also Richard. (Don't tell George that I have any of that MMO though)

[GAHorn]

I seem to recall a thin nylon gasket between the rubber seal and the cap itself. Perhaps a touch of DC-4 between those surfaces would solve the problem. (Type A, Suffix A, ATF fluid is cheaper'n MMO..... no need to pay for the perfume.)

[hilltop170]

I seem to recall a thin nylon gasket between the rubber seal and the cap itself. Perhaps a touch of DC-4 between those surfaces would solve the problem. (Type A, Suffix A, ATF fluid is cheaper'n MMO..... no need to pay for the perfume.)

Maybe, but MMO tastes much better.

[Chris Christensen]

I asked my mechanic about fuel lube once and he just looked at me like I was stupid.
I rememberd about the stuff from a previous shop.
Yeah, he knew what the stuff was, but could not see the cost of it.
OK then, what do ya use? He pulled out a small plastic tube of Vasline Lip Care.
I now have an extra tube of it in whith my spare oil, as well as the one I have usually carry around for lip service.

[n2582d]

I'm planning on removing the retaining chain from my caps. Years ago I had a cap come off a Cessna I was flying. It made a terrific racket and lightly dented the top of the wing. The FAA suggests replacing the metal chain with a non-metallic retainer because of the danger of arcing. Hopefully there is not too much chance of getting hit by lightening in a 170. One would have greater concerns than arcing fuel cap chains if flying around thunderstorms in a C-170. Last year the A-300 I was flying was struck by lightening. The only damage was seat cushion discoloration.

Fuel cap chain.jpg