Ok, so I've decided for the time being to service the caps along with covering them when needed so that moisture won't be able to collect on the cap area.

So I need some help from those who have serviced these before. Outer ring is no problem. But how do you disassemble it to get to the o-ring that seals along the shaft? Anyone have an exploded view of it and/or instructions how it comes apart?

Thanks!

You unscrew the nut at the base of the cap the shaft should pull out. You need to lube the O ring with O ring lube when you put the shaft back into the cap or you can cut it. Vaseline or PET will work if you don't have O ring lube.


Original article:
http://www.csobeech.com/fuel-caps.html

A big hammer would help taking it apart--no idea how to put it back together.

Cary

Mine are red plastic on the bottom and the only thing visible is the cotter pin that attaches to the chain. No nut. I spent several minutes examining it and couldn't see where you could access a point that would let you disassemble it.

I would need to see a pic of both sides then.

The ring around the edge is also more like a gasket (squared edges, not circular).

I'm thinking that is in order too. I'll take some tomorrow. Thanks!

I guess yours are the Wisco ones? I saw some on ebay. I think yours needs the roll pin punched out of the tab and the shaft and base come off together, through the bottom. However your tab may be brittle so cation would be in order.

Yes, I remember seeing the name Wisco on it. I was trying to remember that last night. Thanks for the heads up. I have a spare that is like yours I believe. I'll check that today too. Thanks.

Update:

Well, after mulling it over for a while, I ordered the Monarchs. They arrived last Monday and will be going on tomorrow morning. The cracking is so bad along the square gasket on the Wiscos that I cringed every time I looked at them. So, wish me luck on the install tomorrow morning.

I also talked to Eric at Hartwig about all the issues in the 2007-2009 time frame. He told me that it was a design flaw with the tab holding the cap strap and that it had been addressed. I figure that since the complaints ended around 2009, that they must have addressed the issue. Guess we will find out!

I'll let you know how it goes.

Just for kicks, see if you can get water to seep through the caps by turning them upside down and sealing some sort of cylinder around the bottom surface of the plate the cap screwws into. Maybe a piece of PCV with some silicone and fill with water.

That would be interesting. I'll play with it if I get time.

Well, after a morning at the airport the install is complete! When I left the hanger yesterday, I decided to make sure that we had some good screw drivers that were the size we needed. When I found them, I decided to just give one screw a try to see how snug they were. To my surprise, all of them broke free with minimal exertion!

So, this morning, we showed up and got to work. One gasket had some adhesive on it and we used some solvent to soften it up. All in all I think it came off in 3 or 4 pieces. The other gasket came off in one piece and pretty much rolled off. As we would roll it, we would apply some more solvent and it came right off. The only thing that slowed us down a bit was that I needed to transfer fuel from one tank to a gas can and then to the other tank to get the level down to where we could put a rag on the bottom of the tank. Other than that, it went very smoothly and quickly. All in all a little less than three hours.

After they were on, we went for a half hour flight and found no leaks...although the tanks were only about half full. I'll recheck them again once I top them off. I'm really happy to have that project done and glad that there were no hiccups that might mess up our JC trip! Now I can start the clock on the wallet's rest period before I start talking to Dee about VGs!








This gasket came off and left it almost that clean.


Using the 1/4 bolts as pull tools.


The right hand gasket came off with only a few minor tears around a couple of the holes.




I forgot to get a good straight down shot so these will have to do.

Grassstrippilot wrote: Well, after mulling it over for a while, I ordered the Monarchs. They arrived last Monday and will be going on tomorrow morning. The cracking is so bad along the square gasket on the Wiscos that I cringed every time I looked at them. So, wish me luck on the install tomorrow morning.
....I'll let you know how it goes.

So, now two years later, how about a report on how your Monarch caps have worked out?
The reason I'm resurrecting this thread is that I have a set of Monarch caps that came (uninstalled) with my 180. Thinking about installing them soon, but don't really have a problem with the stock arrangement with the dished flap-jack covers so would hate to do so if the Monarchs have been problematic for you & others.

I've loved them and had zero problems with them. You do have to be careful when topping off to not spill. Once the fuel is above the bottom of the neck where the spring flap closes, it seals it well enough that any extra flow from the hose could fill the remaining area and spill. But I've found it I briefly stick my finger down there to keep the flap cracked open while the hose drains, it's not a problem. I probably should start wearing a rubber glove when I do that. Anyway, I have nothing bad to say about them and am glad I did it. Much better than what I had on there before.

Hope this helps!

I just put Monarchs on a month ago so I'm still in the learning phase. The narrow neck and the flapper do seem to conspire to make things more challenging when filling up.
As Cory said, don't let the flapper pop back up until all fuel has finished dribbling out of the hose. The little cup formed by the flapper doesn't hold much and the rest will be on your wing. Don't ask me how I know!

I'm happy with them overall and I'm sure I'll get the hang of it pretty quick. Look pretty cool too.

I usually fill to about 1/2 inch up into the cup and, if you keep the flap cracked while the hose drains, it won't spill. Much more than that and there is a good chance that putting the cap back on will also cause it to spill. It's not a big deal at all though to slide your finger or whatever down the nozzle to crack that flap open for the 2 seconds or less it takes to drain. And I agree, they do look nice!

Good info! Just bought a set of new Monarch caps at the Alaska Aviation Expo last weekend.

Installing next week

Hopefully no more worries.

Here is part of a post I made over two years ago in this thread.

I've had Monarchs since ~1990 with zero problems that I know about.

Seems to me that fueling with cans would be darn near impossible to do without making a helluva mess with those flappers. The ones on my Monarch caps might accidently fall off between the box and the airplane at install time. The only purpose is to prevent fuel siphoning in flight if you leave the cap off. I'm not gonna say I'll never do that but I'm pretty careful and haven't done it yet in almost 20 years of self-fueling.

I posted on another thread about some auto shutoff nozzles for cans that my hanger buddy uses. I haven't measured them, but they might be long enough to open the flap when inserted. If so, that would make it easy and no mess. The nozzle doesn't open until you push down on it with it already inserted and auto shuts off when the fuel level hits the end of the nozzle.