Cory it's great to see you finally pulled the trigger on getting your own airplane. The Cessna kit will look just like the caps on this 180 which is standard on later Cessna's. I had the Cessna caps on my previous 180 and even bought a set to put on the inboards (long range tanks). I picked up a set from a salvage yard and it seems like they were reasonable, I have Monarch caps on my current Skywagon but I miss the how much easier it was to look into the tank with the Cessna caps. I've had a couple airplanes with the Cessna caps and they never gave me an ounce of trouble FWIW.

gear wrote:I posted on this last year on a different website and just looked at my post. Noticed that 4-5 guys reported they had the same problem. Uncontrolled and unknown fuel siphoning in flight is not a comforting thought.

Garth

Garth,

How old were these installations? Had the owners run ANY auto fuel?

The outfit I worked for changed a number of Cessna airplanes in our fleet to Monarch caps, and many of those airplanes live outside. Nary a problem. That's not to suggest there can't be a problem as you describe. Just wondering if there are other circumstances involved.

MTV

What I did on my 205 is the cessna caps.

Just use the old ones for now but keep an eye out for a newer cessna raised set.
They come across ebay once in a while.

Good luck and long live the 205!!!!!!!!!!!!!!!

mtv wrote:

gear wrote:I posted on this last year on a different website and just looked at my post. Noticed that 4-5 guys reported they had the same problem. Uncontrolled and unknown fuel siphoning in flight is not a comforting thought.

Garth

Garth,

How old were these installations? Had the owners run ANY auto fuel?

The outfit I worked for changed a number of Cessna airplanes in our fleet to Monarch caps, and many of those airplanes live outside. Nary a problem. That's not to suggest there can't be a problem as you describe. Just wondering if there are other circumstances involved.

MTV

I believe the installations are within the last 10 years but i'll check that and re-post if different. Both planes exclusively use Avgas. I wonder how many guys are out there where some siphoning occurs, and they just havent noticed? If you take your cap off, and look at the gasket and you see one side compressed, thats a good indication. The part i keep thinking about, is why they would show up at Oshkosh carrying hundreds of these. Problem is, one of the guys had this issue, replaced his o rings with new from from Monarch, and it happened again - twice.

I've had Monarchs since ~1990 with zero problems that I know about. Lots of car gas also. Here is something that I think will work----it isn't very hard to remove the assembly. Turn it upside down and get some sort of tube, possible PCV pipe that is bigger that the center cap area. Seal the tube to the underside of Monarch, fill with water or gas, and see if it leaks---simple.

I've had absolutely no problems with my Monarchs been on 3.5 years.

I curious about siphoning. Once the fuel level is down just below the flapper deal in the Monarch, how can liquid be sucked out instead of air that is on top of the fuel? Also, can some of the leakage be from where the Monarch plate screws to the bladder----the ~ 8 inch hole in the bladder with a gasket that isn't supposed to leak?

The other nice thing about the Cessna caps is you can use a screw-on tractor funnel with them just like any other Piper or Cessna for filtering mogas through a chamois. The chamois gets soaked with gasoline, and any water will just ride up on top of the chamois without flowing through into the tank. Plus new gaskets for the Cessna caps are just a Napa store away if so inclined. You can find some that are more snug than the PMA replacements.

lesuther wrote:The other nice thing about the Cessna caps is you can use a screw-on tractor funnel with them just like any other Piper or Cessna for filtering mogas through a chamois. The chamois gets soaked with gasoline, and any water will just ride up on top of the chamois without flowing through into the tank. Plus new gaskets for the Cessna caps are just a Napa store away if so inclined. You can find some that are more snug than the PMA replacements.

My Monarchs were 5, 4, 3.5 years ago. I had a problem with the 3.5s. The low pressure on top of the wing, the under wing vent position should be static but could also be low pressure. Have you seen fuel leaving the vents inflight when topped? The possible 2 low pressures can pull up the tank bladder holding the quantity indicator float up, down from the top and in pushing the fuel up to the cap leak. I am working a similar problem with the turbine 206 with new exp caps. The vent location AD doesnt account for all the different wing strut fairings.

Personally, I did the SK on both of my 185's never had any water after that. Installation is quick, just a logbook entry, no 337 or STC to worry about. There are a huge number of Cessnas in the boneyards that have the kits on them, but the caps may or may not be there, since they get harvested quickly. The big bummer on the 185 was the long range tanks have 2 fillers per wing, four kits!

On the flush caps. The big O ring is part of the problem, but the hidden culprit is the one around the locking tab's shaft. The water gets into the little well and goes down the shaft into your tank. Almost nobody does that O ring. replacing that one makes them relatively safe, since almost every larger aircraft uses that style cap. I have had a flameout on a Caravan from water in the fuel, exciting, over the desert at night. Luckily, turbines will burn water, if you keep the ignition on full time. Pistons, not so lucky. That incident was from water in the fuel before it got into the tank, not leaking in through the caps.

SUMP YOUR FUEL even with the best wizard caps water comes in from the vents via humidity, a surprisingly large amount in some cases, even in hangers.

The (killer caps) have got a bad rap. IF you will take the time to maintain them properly they are fine. People don't or won't maintain them and that is what causes the problem. As long as you keep the metal sealing surface in good shape, no pits, paint overspray, pitted and install new o-rings, both large and small on a regular time frame you will have no problems. The lifting tab must be adjusted to a fairly tight fit also. The use of a good o-ring lube periodically won't hurt either. Over the years I've seen so many cracked, pitted and dried o-rings on caps you might just as well leave the cap off, no wonder they leak. It's like anything else on a plane, neglect it and have problems, maintain it and be trouble free. In the 37 years of owning the 185 I have never had a leak and this includes sitting in many heavy rainstorms. They do need to be changed more often on a non hangered plane.
My two cents on Killer caps, Let the flaming begin.
Ron

Currently got the Cessna replacement red caps that came on my ride. Sometimes, after flying for a few hours there is suction pressure when you open the caps, often coming from 1100' airport to 4600' home strip??? I regularly blow in vent to make sure there is no restriction, no one told me to do that its just something that seemed like a good idea after an experience in a 205. Has anyone else has had this problem???

Recently got a brand new set of Monarchs in a trade, which are brand new from factory with STC for my ride. Made the trade thinking they would be a better option than my Cessna's, but not so sure after reading everyone's posts here? Question is...swap them out, or stick with Cessna's and keep Monarchs as spare? They match my polished plane and would look better, but I am more about function for sure. So far, I am thinking about not using them since I heard that it is really hard (impossible?) to see the fuel in filler neck when gassing up.

Ultimately, what is actually better about the Monarchs? Not talking about the "killer caps" at all here. If you had both sitting on the bench, which would you choose?

You have an issue with your vent system. The cap is not the intake point for air, but the vent is. You may have a kink in the rubber portion of the vent line, a nest, or a bladder fold. There is also the flapper valve, which can fail as well, usually open, but they can get sticky and stay shut. Having a condition like that is actually dangerous, you need to find out why or you could be flying a glider soon.

Thanks Dogpilot, is there any way to run something through the vent to check for obstruction? There is free airflow when I blow in the vent-tube. I base out of the ranch and will get it checked by an A&P asap, but would like to do what I legally can at ranch. It just came out of Annual last month and we went through all that and still does it? Of course I have nicknamed that mechanic Ham Hands.

Anybody know a great Cessna 180 Mechanic in Far West Texas, NM, Southern CO area? Maybe this should have been posted in the 182 fuel vent problem thread that was recently on the board, thought it might have had to do with the fuel caps since we just checked the vent???

Well blowing on it really doesn't tell you much other that perhaps eliminating mud daubers as a cause. A lot of the blockages occur only in flight, when bladders shift and the line can kink. You have an issue that appears to be on both sides, as there is a balance line that is supposed to equalize pressures in both tanks. I suspect an installation error in the lines from the vent to the bladder. You can just replace that line with new line and ensure your bladder has no folds up in the corner with a mirror and tiny flashlight. You can remove the flapper unit and clean the unit, some o ring lubricant on the sealing face, after you clean it helps a bit. Your caps should also have a rubber flapper on the base of the cap, at least Cessna ones do (its orange). Gently cleaning it and rubbing o ring lube on it as well. The cap vent is kind of the last defense from tank vacuum.

If you or a previous owner may have used fuel, unknowingly with ethanol, may have caused some of this problem. The older the plane, the more likely it is to have rubber that reacts strongly with ethanol. It does make rubber sticky and swell. Any mechanic should be able to work on the vent system, virtually all 100 series Cessnas are the same. Just look in his/her tool box and pick the mechanic with fewer hammers.

The problem with the monarch cap leaking IMHO is that the thread actually can bottom out on the little tab in the neck that the chain is attached to...therefore preventing the seal from making proper contact with the wing. Look at your threads on the cap and you will see where it's been hitting the tab. File or cut a bit of the thread off thereby allowing the cap to be tightened against the seal instead of the tab inside.

Hope that helps..quess I should have said something about it earlier...like 7 years ago when I fixed the problem myself after no help from Monarch.

Bkn

My killer caps really suck.... 60 years old this year, with most of her life as a ramp rat in rainy / snowy locations and still hasn't managed to kill anyone?n

Sometimes I wonder if we prefer to live the drama than just do the simple stuff like maintenance

Second thought was to buy the caps made by Stay Sealed. Unfortunately it looks like they have stopped making them and I can't find any for the recessed caps anywhere.

Dont' think that's entirely true. Their website indicates that they've stopped making the flush cap covers, but not the others. On my P172D, it has the well-type filler necks, and I use a pair of Stay Seal caps whenever I park it outside. They work very well.

Cary

Cary wrote:

Second thought was to buy the caps made by Stay Sealed. Unfortunately it looks like they have stopped making them and I can't find any for the recessed caps anywhere.

Dont' think that's entirely true. Their website indicates that they've stopped making the flush cap covers, but not the others. On my P172D, it has the well-type filler necks, and I use a pair of Stay Seal caps whenever I park it outside. They work very well.

Cary

This is from their site regarding the flush covers (those are the ones I need and was referring to).


We have made the difficult decision to stop manufacturing of all our
current Flush covers.

We are in the developmental stages of a newer and improved Flush
Cover, and we appreciate your patience through this process.
We have no projected date at this time.

We apologize for the inconvenience, and appreciate your
support, loyalty and interest.
Stay-Sealed Inc


No idea when it was posted. Months, years ago? Who knows.