That's the one that I took the flapper off of.
The other one (flapper intact) is the one I checked.
Actually, I checked that one too-- the fuel REALLY ran out of it!!!

Just an update on my 205 Monarch cap installation.

Hartwig was claiming that his caps have an over-pressure relief and that if the fuel vent isn't perfectly balanced you can have fuel siphon out of the tanks in flight. He emailed a detailed procedure where you basically top tanks, fly once around the pattern and then stop next to a step ladder and run around and listen for sucking or blowing out of the tanks and adjust the vent tubes in 0.020" increments until they are balanced.

The number he gave for the pressure relief was 4PSI. By my calculations at that part of the wing you would run approximately -2PSI just from the lift generation which doesn't leave a lot of margin.

I had replaced the o-ring seals a couple of times and this seemed to make things better for a short period, but my best guess is that there is some difference in the ratchet or the hardness of the seals that causes them to leak. Mine were definitely not leaking from the plate, but from the caps themselves.

I also had water in my tanks after a rain which I had never had before with my "killer caps".

In the end, I finally had enough and replaced the monarch caps with cessna raised inlet types I found surplus. All in all a few AMU in lost fuel, installation, and useless parts and quite a bit of paranoia while flying with these things.

I can't say that I recommend them.

FYI the Cessna caps have been working perfectly since installed.

Well this is all too familiar, I too spent money on caps that a manufacturer won't back. Also being my first post here I really didn't want to bash a company but I have 2 fuel cap assemblies sitting on my shelf to remind me.

I had fuel syphoning out of the cap, mainly with flaps... no stains and barely noticeable on a 2hr flight I had lost almost 34 Gallons! Its a good thing I dipped my tanks for the return flight.

Monarch's excuse was we had opened the package up months before installing on the aircraft and the seals had dried up?? Apparently I'm suppose to lubricate them with some special oil to keep them from shrinking. They were sent back from Monarch with new seals which didn't rest easy with me... Installed them anyway and the fuel quit syphoning out of the tank but still had to sump the tanks after every rain.

Its been 2 years with cessna caps and no water in my tanks.

DT

Quite a few of us found by removing the chain and using a punch to flatten the chain retainer tab - all issues solved. The punch out on a lot of these assemblies is too high and the threaded portion of the cap bottoms out on it instead of on the u-shaped o-ring. This especially becomes an issue after the o-ring gets older and loses some crush. Really a very simple issue the manufacturer should address.

Mark Y. wrote:Quite a few of us found by removing the chain and using a punch to flatten the chain retainer tab - all issues solved. The punch out on a lot of these assemblies is too high and the threaded portion of the cap bottoms out on it instead of on the u-shaped o-ring. This especially becomes an issue after the o-ring gets older and loses some crush. Really a very simple issue the manufacturer should address.

Given some of the ADs that have come out lately makes this is AD worthy in comparison. There likely have been no SDRs filed or accidents directly relating so it's likely never gotten back to TC.
I agree that the manufacturer should address this. I know I won't spend money on these caps, but I've had great luck with cessna caps and not found much water in my tanks.

Sent from my SM-G870W using Tapatalk

I just replaced my 63 year old left bladder so thought I'd take a pic of my original Bill Barton Monarch cap and plate. Notice the chain doesn't have the punched deal to hold the chain and the flap does have a check valve and rubber gasket that does holds fuel nicely. I'm glad I have the original's.

Looks like your photobucket sprung a leak.

What do you mean Hotrod, I see pic's I posted

I don't see the pics either



I think the chains are a hoaky addition anyway. i would prefer a loose cap is gone rather than have a dented up wing skin.

Okay, I see what you guys are talking about when I switched from Chrome to Firefox.