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Such A Thing As Lube For the O-Ring Fuel Cap?

mbauer

Well Known Member
Such A Thing As Lube For the O-Ring on the Fuel Cap?

My fuel caps are getting harder and harder to remove and then put back. When I first purchased my RV-6 it had some kind of "product" that seemed to help, now that stuff is acting like a glue.

Is there a lube of some kind that I can use to stop the O-rings from sticking?

Or best to buy new O-rings and clean the cap of all residue?

Caps are in great shape, except for the O-rings sticking when trying to fuel...

Best regards,
Mike Bauer
 
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scuba shops sell pure silicone grease to be put on o rings.so i am sure you can find it online.fuel doesn't dissolve it.
 
Push down

You probabably know this but I picked up a helpful tip here on the forum. With the lock lever flipped up, push it down . Then rotate/lift the cap out. I use EZ turn and this procedure makes it very easy to remove caps.
 
pick your poison, anything is better than nothing. proper adjustment is critical. not to tight, not to loose.
IMG_1979.jpg
 
Lube for ring

For 17 years I've used a drop of oil from the dipstick, spread around the o ring then exercise the assembly. You have at least five quarts with you at any time.
 
Parker O-ring Lube

I use purpose made Parker O-ring lube (sparingly). I'll look when I get to the hangar and edit this post with the specifics.
 
The mystery product is probably EZ Turn or some other brand of fuel lube:

http://www.aircraftspruce.com/catalog/cspages/ezturnlube.php?clickkey=9406

Dismantle the caps, remove all the old lube, re-lube the o-rings sparingly, assemble and readjust the caps. Don't need new o-rings unless they are somehow cracked or damaged.

I like the chapstick idea. EZ Turn is sticky.

EZ Turn is not workable when it is cold out...you may not be able to remove the cap without warming them up. That is the very worst thing to use on fuel caps (unless you live in Alabama, for example...). Take the caps apart and clean as much of that glop off from all the components as you can. It can only be removed by rubbing it off - nothing reasonable will dissolve it. I've used Tri-Flow every few months for 15 years or so, works well. When the caps are adjusted properly, they should require very little force to click the tab down, and should pull up out of the tank very easily also when opened.
 
Yep.

You probabably know this but I picked up a helpful tip here on the forum. With the lock lever flipped up, push it down . Then rotate/lift the cap out. I use EZ turn and this procedure makes it very easy to remove caps.

I agree with this and Turbo's answer. With the new brown "O" rings you don't need much lube at all. We clean them from time to time and just finger wave them with some fuel lube. Turbo is on the money here as the mount ring has a cone shape as it tapers up and out of the neck at the cap. So you just need it adjusted so that it will lightly hold in place. anything more and you are compressing the "O" ring into the flange face. That will make it stick and drag when you try to remove the cap. That taper will hold the "O" ring from pulling out of the neck. I know it is a learned thing as to how tight to adjust the nut for the cap "O" ring adjuster nut. But it is not a lot.
Just what we have noted over time. Yours, R.E.A. III # 80888
 
A few drops of avgas

I dip the fuel nozzle in the tank and put a few drops of gas on the o ring. Make sure when you flip up the tab push down on it. Over 1000 hours no issues.
 
I use purpose made Parker O-ring lube (sparingly). I'll look when I get to the hangar and edit this post with the specifics.

I would not use the Parker lube on the fuel caps - it is designed to swell the o-rings.
I use EZ Lube. Once you put a LITTLE on it will last for years.
 
speaking of fuel lube/e z turn...

Anyone know of a similar product, usable in the old brass cone fuel valves, that can be purchased from local vendors or a free shipping source like Amazon Prime? I really don't need anything else from Spruce right now, & hate to pay as much for shipping as the product value.

(And no, I don't see any need to replace the valve...)

Charlie
 
EZ Turn is not workable when it is cold out...you may not be able to remove the cap without warming them up. That is the very worst thing to use on fuel caps (unless you live in Alabama, for example...). Take the caps apart and clean as much of that glop off from all the components as you can. It can only be removed by rubbing it off - nothing reasonable will dissolve it. I've used Tri-Flow every few months for 15 years or so, works well. When the caps are adjusted properly, they should require very little force to click the tab down, and should pull up out of the tank very easily also when opened.

A giant +1 on this one! I used Fuel Lube on mine, then found I had to use a heat gun to get the caps off in the winter. Totally useless in anything other than balmy temperatures.

Most home renovation / hardware stores carry pure silicone grease for plumbing O-rings (Home Depot is where I got mine - it comes in a little blue plastic tub with a flip-up lid and costs under $10). A little container of it, maybe half an ounce, has lasted me at least a decade. It takes only the lightest wipe of a finger dipped in the silicone grease to keep the fuel cap O-rings working perfectly for several months.

Note this silicone lube is also helpful in some of the older, more traditional fuel selector valves where O-rings are employed.
 
Stem o-ring

Use LPS-4 on the stem o-ring. Work it in a couple times and repeat every couple months. Just a little dab will do ya.
 
Thank you For the Replies!!!

Sounds like it was the EZ stuff. Think I'll clean them up and use the tri-flo for now. Only way I can get them out is to make sure that I press down on the vertical bolt.

They bind when trying to rotate them and lift. Same issue when trying to get them back in. The EZ is like a glue that won't let go...

There is a O-ring specialty shop down the road, 1/4 mile, that deals with oilfield related items, thinking I might go talk to them to see what they have.

I know you can remove silicone caulking with regular gasoline, that is why silicone isn't recommended to use around hydrocarbons.

Best regards,
Mike Bauer
 
The only lube I've used is an occasional swipe of avgas (or auto gas) on the big o-ring when filling the tanks. Having the caps adjusted properly is the other factor.
 
Anyone know of a similar product, usable in the old brass cone fuel valves, that can be purchased from local vendors or a free shipping source like Amazon Prime? I really don't need anything else from Spruce right now, & hate to pay as much for shipping as the product value.

(And no, I don't see any need to replace the valve...)

Charlie

It was called Lubirplate......comes in a small toothpaste type tube.

But, your valve does not need any lube. The spring is too strong. Cut one loop off of it. You can do this without removing the valve.
 
Thanks, but Lubriplate seems to make hundreds of products. Can you narrow it down a bit?

The valves sold with the older kits do seem to need lubrication; at least the ones I've used had fuel lube in them. They are brass on brass; not like the current version.

Charlie
 
130-AA.... This grease will wash off with gasoline. It will work with propane or natural gas.

Your best bet would be to replace the valve for $55....
 
Use Krytox, pure PTFE and not soluble in 100LL

Having tried many of the lubes listed herein the easiest was a drop of 100LL every time the cap came off. Grease, EZlube and others washed off after 4-5 flights and back to dropping fuel. So . . .

I did a little research on the solubility of DC-4, DC-2, EZlube, Lubriplate Lithium, and many others in 100LL. All were soluble in gasoline

I finally found a pure PTFE product called Krytox GPL-205. It claimed not to be soluble in gasoline so I cleaned the caps and o-rings then applied the Krytox. Three BB sized balls and worked it around. A tiny smear on the pivot too.

8-9 flights and three fills to tip top and it the operation is still butter smooth. If this works, a small tube will last till TBO.

BTW - a 0.5 OZ tube was over $20, so not the cheap solution but hopefully it is lasting.

I think I need better bait. It's clear many people don't read past the first sentence. With this lube, the cap does not stick and need the press after lifting the tab.

edit 8-11-22: my caps have not leaked, nor stuck even once since using Krytox.
 
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The only lube I've used is an occasional swipe of avgas (or auto gas) on the big o-ring when filling the tanks. Having the caps adjusted properly is the other factor.

Just a couple of drops of gas a couple of times a year seems to keep my caps happy. EZ Lube, etc. is just too sticky for this use.
 
What do you use to clean this sticky stuff off?

Michael-

I used isopropyl alcohol and naphtha (separately of course) to remove all residual as I has tried several things in the past year. I'm not sure which one is good for EzTurn, but between the two and the rubbing, the o-rings were clean.
 
Best Tip

You probabably know this but I picked up a helpful tip here on the forum. With the lock lever flipped up, push it down . Then rotate/lift the cap out. I use EZ turn and this procedure makes it very easy to remove caps.

THIS is the best tip in this entire thread. Lift the lever to the vertical unlatched position then while holding the lever in the vertical position, push it straight down "into the gas cap". I tried this for the first time yesterday and it worked like a charm! The cap then comes out of the tank with zero resistance!

Skylor
 
Having tried many of the lubes listed herein the easiest was a drop of 100LL every time the cap came off. Grease, EZlube and others washed off after 4-5 flights and back to dropping fuel. So . . .

I did a little research on the solubility of DC-4, DC-2, EZlube, Lubriplate Lithium, and many others in 100LL. All were soluble in gasoline

I finally found a pure PTFE product called Krytox GPL-205. It claimed not to be soluble in gasoline so I cleaned the caps and o-rings then applied the Krytox. Three BB sized balls and worked it around. A tiny smear on the pivot too.

8-9 flights and three fills to tip top and it the operation is still butter smooth. If this works, a small tube will last till TBO.

BTW - a 0.5 OZ tube was over $20, so not the cheap solution but hopefully it is lasting.

I think I need better bait. It's clear many people don't read past the first sentence. With this lube, the cap does not stick and need the press after lifting the tab.

The EZ community has been using Krytox for their fuel cap O-rings and fuel valves for 30+ years. Krytox 205 was originally developed for the cargo bay door hinges on the Space Shuttle Orbiter - it doesn't outgas in the vacuum of space. As stated, crazy expensive but I've been using my tube of Krytox since 1983... and still have some left. I'm now using blue fluorosilicone O-rings; the Krytox is compatible with them per the manufacturer.
 
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THIS is the best tip in this entire thread. Lift the lever to the vertical unlatched position then while holding the lever in the vertical position, push it straight down "into the gas cap". I tried this for the first time yesterday and it worked like a charm! The cap then comes out of the tank with zero resistance!

Skylor

This works because the cone drops away from the big O ring. If the tab needs to be pushed down, the shaft O ring is dry and holding it from dropping.

The lube problem comes into play when you install the cap and need the O ring to expand and slide up the cone. If it does not slide easily, the pin takes the excess load till it fails. The cap should never be adjusted so tight that you can't lift the tab with your finger.
 
You probabably know this but I picked up a helpful tip here on the forum. With the lock lever flipped up, push it down . Then rotate/lift the cap out. I use EZ turn and this procedure makes it very easy to remove caps.

Huh...did not know this and tried it today and this really works. Very cool!
 
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Thank You!

Just wanted to say thanks to all who posted.

Used LPS2 to clean the "glue" off of the O-rings. Lots of rubbing, once clean, lubed and re-installed. What a difference. The big help was the push the shaft down to help free the o-ring.

Best regards,
Mike Bauer
 
Just wanted to say thanks to all who posted.

Used LPS2 to clean the "glue" off of the O-rings. Lots of rubbing, once clean, lubed and re-installed. What a difference. The big help was the push the shaft down to help free the o-ring.

Best regards,
Mike Bauer

You forgot the Krytox 205. The lubricity is persistent and the shaft does not need to be pushed in because the o-ring slides and drops the lower cone. If you must push the center, it is the first indication that the lubrication has failed.

You started a good thread.
 
You forgot the Krytox 205. The lubricity is persistent and the shaft does not need to be pushed in because the o-ring slides and drops the lower cone. If you must push the center, it is the first indication that the lubrication has failed.

You started a good thread.

Thank you Bill.

We use Krytox at work, safe around Oxygen use. We use it for lubricating items located near welding oxygen cylinders.

The LPS works great for the gas cap.

Best regards,
Mike Bauer
 
My fuel caps were a little sticky so I took a few minutes the other day and showed them a little love.

I ordered a small tube of Krytox 205 lube off of Amazon. I bought the $42 tube because I was afraid I would outlive the $20 tube and I was fairly certain I wouldn?t use the 8 ounce $136 tube. I?m very practical this way.

The end result is that I now have very smoooooth gas cap release mechanisms. I?m not sure, but I suspect hitting all the moving parts with a Scotchbrite wheel was as effective as the magical lube.

I?m probably good for another 20 years! Seriously though, this is the kinda stuff that people do who really care about their airplanes. I?ve looked at 3 Christen Eagles, a Pitts S2A, a 7AC, a GCBC Citabria in the last month and I can?t believe how people [don?t] care for their aircraft.

And no, I won?t be selling Chuck?s RV-3!
 
--- snip ---

I ordered a small tube of Krytox 205 lube off of Amazon. I bought the $42 tube because I was afraid I would outlive the $20 tube and I was fairly certain I wouldn?t use the 8 ounce $136 tube. I?m very practical this way.

--- snip ---


Just looked on Amazon and the 2 Oz $40 tube is out of stock.

Looking for your opinion on how many caps you think the 0.5 Oz $20 tube will do?

How long do you think the cap(s) will go before they need another coat of lube?

I am ready to buy some. Your reason for the 2 oz tube would be the same logic I would use to get it so am asking if the 0.5 oz size may last 20 or 30 years.
 
If Krytox 205 lube holds up as well as EZ Turn then yes, it will last 20 years. You are only rubbing on a small film on the "O" rings.
 
I'm sure I'm repeating myself - but use some Tri-Flow twice a year on moving parts and o-rings of gas caps, problem solved. A can is about $12, will last about 200 years if only used to lube fuel caps. Of course, it is really good for many things.
 
I just keep a light covering of fuel lube on the O-ring.

And the pushdown trick really helps!
 
Just looked on Amazon and the 2 Oz $40 tube is out of stock.

Looking for your opinion on how many caps you think the 0.5 Oz $20 tube will do?

How long do you think the cap(s) will go before they need another coat of lube?

I am ready to buy some. Your reason for the 2 oz tube would be the same logic I would use to get it so am asking if the 0.5 oz size may last 20 or 30 years.

I’d probably wait for the 2oz. tube if I was doing it again. The 1/2 ounce version would probably do the caps 15 times, but I’m already finding new uses for the stuff. I’m also a sucker for buying in “bulk”—if you can think of 2 ounces as bulk!

Edited to add: I’m not sure how long my caps will stay nice before the next treatment. As I mentioned, mine was a multifaceted approach of removing some gunk and corrosion with scotchbrite as well as lubrication. I don’t know which operation helped the most. I wasn’t too scientific in controlling variables! ��
 
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Just looked on Amazon and the 2 Oz $40 tube is out of stock.

Looking for your opinion on how many caps you think the 0.5 Oz $20 tube will do?

How long do you think the cap(s) will go before they need another coat of lube?

I am ready to buy some. Your reason for the 2 oz tube would be the same logic I would use to get it so am asking if the 0.5 oz size may last 20 or 30 years.

Since Krytox 205 will not dissolve in gasoline or evaporate I have bet on the .5oz lasting a long time. For the test phase, it was used sparingly (a pea per cap), just a very very thin film. Now to see how long it remains free when releasing.
 
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I'm sure I'm repeating myself - but use some Tri-Flow twice a year on moving parts and o-rings of gas caps, problem solved. A can is about $12, will last about 200 years if only used to lube fuel caps. Of course, it is really good for many things.

But Alex, the PTFE is the only ingredient that that does not dissolve in gasoline, 1.3% so that makes the PTFE cost $153/oz. :D:D
 
But Alex, the PTFE is the only ingredient that that does not dissolve in gasoline, 1.3% so that makes the PTFE cost $153/oz. :D:D

Bill - good one! Reminds me of a calculation I did on a tiny bottle of rear window defroster repair paint - it was $22,000/gallon...

How does the Krytox do when you put the cap in a freezer at -10F or so? That is the problem with the EZ Turn or Fuel Lube that people from the south keep touting...
 
I paid for and ordered the 0.5 Oz $20 tube.

Today, the package arrived and had a NEW unopened 2 Oz tube. The weight of the tube with contents was 2.3 Oz.

Will re-do my fuel caps in the near future. The fuel lube has worked well for 20-years. Most of the time I was in SoCAL with no issue. They work ok in cold for 4 years in PA and 1 year in NC. A lot of that may have something to do with me not flying in Wx where the temp is below 32 F.
 
ez turn fuel lube

Bill, My 3 month test of fuel lube in a jar of avgas shows no signs of dissolving. The parts that we put in the jar have different shapes including some threads the size of hair. I have been using the stuff on my caps for more than a year with good results but you do need to push the tab down to release the o-ring. I will report in another 3 months. Ron
 
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