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Fuel tank cap/lever/tab pins

jetjok

jetjok

Well Known Member
Fuel Cap Adjustment and Roll Pin

Not wanting to drift from the other posting about fuel cap openers, I am starting a new thread (which probably has been covered numerous times) about the roll pin on the fuel caps.

scsmith said:
My wings were quickbuild, and the caps came installed, and I have not tried to adjust them. They do seem maybe a tad tight. I really worry about that roll pin, tempted to put a piece of drill rod in there.
Click to expand...

I had numerous instances where the roll pin fractured, and left me high and leaky at out locations. I changed over to .062 (1/16") drill stock and have had no further problems.
 
1/16" stainless steel welding rod also makes a fine pin. I carry a short length in the flight bag and it can be cut with wire cutters if a pin needs to be replaced.
 
Good suggestions. I have replaced a pin on a cross-country BUT...had a spare cap to keep the fuel in until I made the repair. I also carry other spare fuel cap parts.

If someone has the adjustment/maintenance info/website, that would help in this thread.
 
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jetjok said:
Not wanting to drift from the other posting about fuel cap openers, I am starting a new thread (which probably has been covered numerous times) about the roll pin on the fuel caps.



I had numerous instances where the roll pin fractured, and left me high and leaky at out locations. I changed over to .062 (1/16") drill stock and have had no further problems.
Click to expand...

Mark:

I did the same 13-years ago when I started flying my RV-6. This replacement was Standard Operating Procedure back then. Looks like it did not get passed on to the newer guys. I would have sworn that there was a long thread on the old Matronics RV-List 14 or 15 years ago.
 
Good reminder

I keep meaning to put a length of SS welding rod in my bag...I'll do it NOW!..:)
 
RV6_flyer said:
Mark:

I did the same 13-years ago when I started flying my RV-6. This replacement was Standard Operating Procedure back then. Looks like it did not get passed on to the newer guys. I would have sworn that there was a long thread on the old Matronics RV-List 14 or 15 years ago.
Click to expand...

Gary,
I knew that I should have searched the archives before starting a new thread!

http://www.vansairforce.com/community/showthread.php?t=51599&highlight=fuel+cap+roll+pin&page=2

Leave it to me to re-invent the wheel!!
 
Fuel caps

I gotta tell you.. I've done the same 1/16 drill stock pin replacement after having to fly home with a duct taped fuel cap. Lots of trouble with the caps leaking, and hard to adjust properly to allow them to be removed easily without excessive leakage. I found the Usher caps to be a constant headache, and this year at annual I replaced them with Andair locking fuel caps and the bonded rings. Best upgrade to my aircraft so far. Easy to operate, secure,and they just don't leak. Easy to install, and expensive. Worth every penny. I am building another plane now, and would love to hear what alternatives others may have used for fuel caps.
I sure wish Van would consider another fuel cap alternative for his fine aircraft. The poor caps are the only real complaint I have about the RV!!
Sorry, didn't mean to hijack....

Regards,
Chris
 
lubrication

Since it hasn't been mentioned yet, its a good idea to lubricate the caps regularly. I started doing this a few years ago and haven't had a problem with a pin breaking since.
 
I coat the "O" rings with lubriplate at every condition inspection and have had zero trouble in over 17 years.
 
Mel said:
I coat the "O" rings with lubriplate at every condition inspection and have had zero trouble in over 17 years.
Click to expand...

I also lube the "O" ring. I use EZ turn from Spruce. It does not get below 30 here. Luberplate might be better. Before lube, it was an effort to install and remove the cap. Looking at how the cap works, you can see that the o ring must slide on the taper for it to work. You must lube the o ring for it to slide properly.

I can now open my caps with just my finger. No leaks..... and I have only applied the lube to the rings once about five years ago....... but that's ez turn. I have never tried lubriplate but it would be better in colder climates.
 
A simple push

Once you've raised the lever on the fuel cap just push straight down and it will release pressure on the o-ring and the cap will just pull right out. If you don't push, the o-ring is still expanded and is hard to pull out.
 
RV8iator said:
Once you've raised the lever on the fuel cap just push straight down and it will release pressure on the o-ring and the cap will just pull right out. If you don't push, the o-ring is still expanded and is hard to pull out.
Click to expand...

Yeah, I was just getting ready to say the same thing. I was missing that critical piece of info for the first couple of weeks of flight.
 
Fuel cap lube

There is also a second 'O' ring around the center
shaft that should be lubed at least once in a while.

I was also unhappy with my fuel caps until a RV friend
told me about lubing them and pressing down on
the center tab before removal. Made a big difference.
Tom
 
lubing does the trick

but I havent found one that lasts. What Lubriplate product are you using Mel (or others)??? Thanks Guys
 
Type of lube for fuel cap

I use EZ-turn (fuel lube) and it is still on
the outer 'O' ring after a year when I do
my condition inspection. It makes the cap
stiff in cold weather but I am still able to
remove the cap.
Tom
 
Thanks for the hint RV8iator.

I pushed down on the tab before removing the fuel filler cap today and it cam out with zero effort. What a great bit of info...
 
RV8iator said:
Once you've raised the lever on the fuel cap just push straight down and it will release pressure on the o-ring and the cap will just pull right out. If you don't push, the o-ring is still expanded and is hard to pull out.
Click to expand...

Without lube on the "O" ring, it will not slide down the taper. Pushing on the shaft will release the lower taper part and allow the O ring to shrink. If you lube it, the O ring will force the lower taper down.

Stress on the pin happens when you press down the cap lever. If the o ring is dry and drags on the sides of the taper then the pressure required to close the cap lever increases to the point of pivot pin failure.

I think I will try tri-flow..... EZ turn is really sticky. But that is what came on my new caps..............................:eek:
 
one other thing is the adjustment or tightness. start with it adjusted so when the tab is down the cap will turn. keep increasing the tightness and testing till the cap wount turn. thats it, not too tight, lubed, the pin will last for years. as per mels directions last year. thanks mel.
 
I just broke my 3rd fuel tank cap pin in 8 years. Maybe 3 in 8 years doesn't sound so bad but it always seems to happen at the worst possible time. I'm thinking about drilling it out for a little heavier-duty pin. Has anyone come up with a soluton to this.
 
My original fuel cap had a roll pin that broke. I ordered some replacement pins from Van's, and the replacement pins were solid steel. I also took this opportunity to replace the small o-ring and give it a coating of fuel lube. Works great.
 
Broken Fuel Cap Tab

During my preflight this morning, I had this happen:

imagejpg1_zps7b63f04b.jpg


Fortunately, my hangar mate has a pair of RV7 wings stored in the hangar. I have to say, it was a bit difficult mounting those wings to my 9 but that solved the problem! RIM SHOT!

But seriously folks, I borrowed a cap from his wings which saved the day.

Has anybody ever had this happen to them? Any tips regarding prevention?

Short of spending bucks for an upgraded cap from Vans, which involves bonding, I would think the best bet would be to order the same type of cap plus a spare. Thoughts?
 
I just ordered the fancy caps from vans and have unused original ones. Make me an offer? :)
 
Happened once to me. You can fix it with a new roll pin. I try to keep the o-ring lubed, and not set too tight, and the whole thing operates a bit smoother. I carry an extra fuel cap just in case.

Paul
 
I also had this happen to me. Ordered extra roll pins from Vans, but in the mean time I cut down a properly sized drill bit shank and use that. Sorry, I do not remember the size of the drill bit.
 
My first assumption would be that the closed compression setting of the big O-ring (position of bottom plate and nut) is set too tight.

Reset a bit looser and grease the mechanism with fuel lube or equivalent.

Of course, it could be a one off failure of the pin. :rolleyes:
 
There is an old thread about this - replace the roll pin and keep the O-ring lubed (fuel lube) plus not too tight. Check at annual or whenever it gets sticky. And carry a spare in your travel kit, or at least some duct tape.

Greg
 
Quite common. A lifetime supply of new roll pins is very cheap. This is a time limited item on our annual condition inspection check list. It only takes a couple of minutes to press in new roll pins every couple of years.
 
I think you can find the pins at Lowe's in their hardware drawers. I used a steel mandrel out of a pop rivet until I found a replacement pin. I maintenance these caps a couple of times a year, putting lube on the gasket and making sure they are not too hard to operate. The tell tale for me when they need attention is when the lever gets difficult to close down.
 
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I keep a short length of 1/16" stainless steel welding rod in the flight kit. A new pin can be cut from the rod in a few seconds with a pair of cutting pliers. I've been flying one of the repaired pins for a dozen years. Keeping the caps properly adjusted is the key to avoiding broken pins.
 
Had that happen a couple of times on my RV-6. All you can do is install a new pin. Make sure the pre-load is not excessive. When you seat the cap it should not take excessive force. I keep spare pins in my shop. I also fly with a couple of spare fuel caps to get me home in case it happens on the road. I think the pins Van's uses now are heavier gauge.
 
noelf said:
I also had this happen to me. Ordered extra roll pins from Vans, but in the mean time I cut down a properly sized drill bit shank and use that. Sorry, I do not remember the size of the drill bit.
Click to expand...

A piece of drill bit IS WAY TO GO!!! I changed mine out on the recommendation from my tech counselor (Jack Hakes) on day one, and you can imagine how many times my caps have been off and on... I also put some fuel lube on the 'cam' of both sides of the lever (using a small blade screwdriver) every couple of months too :) Rosie
 
There was a thread 5 or 6 ?? years back, told about increasing the radius on the rear/lower corner of the lock tab. You only take off a small bit, makes the tab a lot easier to lift, and less stress on the hinge pin. The cap still seals just fine also.

I did this to my caps and it helped.

By the way, if using fuel lube on the "O" ring---------only use a small amount, and keep it in the groove.

Dont make the mistake of lubing the outer surface of the "O" ring where it seats in the tank.........:eek:
 
Mike S said:
There was a thread 5 or 6 ?? years back, told about increasing the radius on the rear/lower corner of the lock tab. You only take off a small bit, makes the tab a lot easier to lift, and less stress on the hinge pin. The cap still seals just fine also.

I did this to my caps and it helped.
:
Click to expand...

T'was Rocketbob, Mike

I think it is a tip in the building tips section now.
 
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