Topic: AN fittings - leak problem

[anotherCB]

I am using some AN-10 fittings for my custom oil tank setup. I know that I should not use any type od sealer or teflon tape where I connect the hose to the fitting.

But what about between the fitting and the bungs that are welded to the tank? It looks like oil is leaking out there. In the picture, it is the bottom of the fitting that is attached to the tank. Can I/Should I use any sealant or teflon tape there?

[crazypj]

Check you have correct ends, if the taper seat is OK try loosening slightly and 'wringing' the two pieces together.
 They should be self centering.
Over tightening can cause leaks (particularly if you have alloy fittings)

[72500john]

is the part you welded to the tank an AN fitting? AN flared fittings are 37.5 degree flare and SEA are 45 degrees. if all is well try a little fine valve lapping compound and lap the seat for the flare.
are you using stainless or aluminium fittings?

[anotherCB]

I had the tank custom made, and I asked for AN bungs. I am pretty sure the bungs are AN since the seat looks as if it would be correct for my fittings, but i will doublecheck with the builder. If worse comes to worse is it ok to use some kind of sealant like Teflon on the bungs or would I need other bungs welded on? The thread seems to be correct.

[crazypj]

I wouldn't use Teflon tape or sealer, I would probably use a thin dished copper washer, even if I had to make it

[72500john]

dont know how well this pic will post..but is this something like what you have welded into your tank?

[anotherCB]

72500 John, yes I believe that's exactly it. As far as I understand there is a seat on the bung (as you can see in your pic) and the same kind of seat in the fitting I attach to it.

Crazypj, Since I think those seats provide the seal I don't believe I can use a thin copper washer like you suggest. That would defeat the purpose of the seat. Or do I misunderstand?

[72500john]

i am guessing this is a low pressure system as in under 100 psi? these fittings will easily hold 3000 psi. try the valve lapping compound trick. if that does not work i will look in my tool box and see if i have any conical seals..aka soft aluminum seals that match the flare angle. number 10s you say you used. how many do you need?
i will pm you tommorrow if i have any. but try the valve grind fist..have sealed many 3000 psi seepers this way.

[anotherCB]

I am afraid the lapping trick won't work, because the seat is inside the fitting and only when I completely screw the fitting on the bung, the seat surfaces touch each other.

Engine pressure is 70 psi max and the tank is vented, so tank pressure should be very low.

[Irukandji]

my 2cents...Does the nut slide up the tube at all? If nut is a loose fit on the tube I think you just have it cocked a bit ( from pressure of the hose) when its tightened.
Nut doesn't hit the stop on the bung does it?

[72500john]

yes it will. try this. put a little fine lapping compound on the nipple( the part welded into your tank). screw the line/fitting almost all the way on until it just makes contact with the flare. grab the back part of the hose and rotate it back and forth in the clokwise and counter clokwise direction to lapp the joint. opps!! this may not work if you did not use flex hoses..is it hard plumbed with stainless pipe?

[crazypj]

Crazypj, Since I think those seats provide the seal I don't believe I can use a thin copper washer like you suggest. That would defeat the purpose of the seat. Or do I misunderstand?

 I was having brain fade earlier, conical seals are what I was thinking.
72500 John gave correct information, you'll get matte finish and you can then see how much contact you actually have

[MRieck]

Earl's used to make snap on fittings for the male end. That stuff was new...you shouldn't need that part (unless the male end got banged around). If you assembled the lines I think there is a better chance they are leaking...not the actual male/female ends.

[anotherCB]

I am using flexible lines, so I guess what I will do is drain the oil, getting the hoses off and then trying to determine with the compound whether I the seat has a good contact. I am almost sure that the leak is not where the hose is connected to the fitting. I will try to post some pics tomorrow, that should help. For now, thanks everyone, I will keep you posted and maybe ask more questions 

[Rigid]

yes it will. try this. put a little fine lapping compound on the nipple( the part welded into your tank). screw the line/fitting almost all the way on until it just makes contact with the flare. grab the back part of the hose and rotate it back and forth in the clokwise and counter clokwise direction to lapp the joint. opps!! this may not work if you did not use flex hoses..is it hard plumbed with stainless pipe?

72500john knows his stuff and provided good advice.  I would only add that a light coating of prussion blue on the flare might show the contact area, or any gaps. 

[754]

 my advice use NPT bungs to weel in...easy to chase.
 Then use NPT to AN fitting, then your hose bolts to that.

 if the AN bung warped in weelding its hard to fix, plus they bugger them if you chrome it, plus if they simply uses an npt-An fitting in steel they are often made from leaded barstock...(harder to weld properly)
 
 Saw a set of male/female chasers for tapered fitting seats at a yardc sale once, so they probably exist...

[anotherCB]

Thanks guys, that gives me some options. It's the wife's BDay this weekend, so my garage time might be limited , but I'll keep you updated how it goes.

[72500john]

please send include some pics when you have a chance..always glad to help. good luck with your project and from the list of bikes you have it looks as you have many!

[anotherCB]

Will post some pics soon.

Most of my bikes are "Had" though, just having the Harley and the CB.

[anotherCB]

Ok, here a pic. Tank is on and the leak problem is basically under contol. It seems that just tightening the fittings real good solved the issue of leaking at the fittings. Unfortunately the line I am using is Teflon and the connection at the transmission is hard to get sealed since the hose is needs to be bent at a radius that is too tight. Might have to find another adapter or use a rubber hose.

As you can see I am using a tiny "antigravity.com" battery. Works like a charme, just need to mount it under the seat now.

[anotherCB]

Forgot the pic.....

[anotherCB]

Works like a charme now. I know y'all like pics 

[crazypj]

That's pretty neat, how much oil does it hold?

[anotherCB]

It measures (in cm) 24 high, 12 wide (in the middle) and 6 deep, that comes out to 1.8 litres. First I thought it might not be enough and I am not sure what happens at a 100 degree day on the track, but I have been riding foridden it for 10 miles between 90 and 100mph and the oil temp was just slightly above 200 degrees.
The good thing is, it sits right in the wind, that helps a lot.

[anotherCB]

True, but less is more for me :-) so hopefully I won't need it!