AN Fitting Experts —Advice

[TXCarGeek]

The fuel feed line to the injector rail on my ‘08 BMW 550i with 238k miles has developed a small leak. The connection on it cannot be serviced separately without replacing the entire rail.

Is it possible to convert this fitting to AN line fittings? The hard line from the tank is just metal, not sure of the size, and the hose to the rail is rubber with the quick disconnect.

Any advice would be greatly appreciated.

 

[RooflessVW]

I would think so. I have a couple ideas but none are fully realized yet.

I just wanted to say bravo for taking a 550i so far.

 

[Trav]

The fuel feed line to the injector rail on my ‘08 BMW 550i with 238k miles has developed a small leak. The connection on it cannot be serviced separately without replacing the entire rail.

Is it possible to convert this fitting to AN line fittings? The hard line from the tank is just metal, not sure of the size, and the hose to the rail is rubber with the quick disconnect.

Any advice would be greatly appreciated.

I did one of these on a VW a few years ago, there is an O ring(s) in the metal fitting, you can get it out with a pick and replace it.
This is one for an example, it may not be in your fitting. You can get one commercially or contact me.

https://www.ecstuning.com/b-genuine-bmw-parts/o-ring-priced-each/17222245358/?gclid=EAIaIQobChMI9pyNquD-_gIVB9DjBx1WIghOEAQYBSABEgIFWvD_BwE

 

[atikovi]

Maybe an S.U.R.&R. kit would work?

KP1200 - SUR&R

surrauto.com

 

[JustChuck]

If its not an Oring you can replace as mentioned above, I would replace the fuel rail and line. Fuel leaks are not something you want to take a chance with.

 

[NYEngineer]

I'm pretty sure there's an O ring in there that can be serviced. If you're bent on converting it to AN, I had to do that once on a hot rod conversion. I was putting a four barrel EFI throttle body where there was once a two bbl. I removed the fuel lines and brought them to a big hose supply shop. They silver soldered to male AN fittings to the lines and I was then able to use Push lok hoses to connect the new TBI. Worked great.

 

[Wrenchturner44]

There are quick connect to AN fittings now available. I am not sure if this will help your cause or not, but they are not inexpensive.

Aeromotive 15118 Aeromotive AN Quick-Connect Adapter Fittings | Summit Racing

Free Shipping - Aeromotive AN Quick-Connect Adapter Fittings with qualifying orders of $109. Shop Quick Disconnect Fittings at Summit Racing.

www.summitracing.com

 

[TXCarGeek]

I did one of these on a VW a few years ago, there is an O ring(s) in the metal fitting, you can get it out with a pick and replace it.
This is one for an example, it may not be in your fitting. You can get one commercially or contact me.

https://www.ecstuning.com/b-genuine-bmw-parts/o-ring-priced-each/17222245358/?gclid=EAIaIQobChMI9pyNquD-_gIVB9DjBx1WIghOEAQYBSABEgIFWvD_BwE

I just gave you a call, that would be perfect if I can fish out those o-rings. It'll be a tight squeeze for sure but would be the quickest and likely cheapest solution. Just don't know what size they might be.

 

[TXCarGeek]

I would think so. I have a couple ideas but none are fully realized yet.

I just wanted to say bravo for taking a 550i so far.

I appreciate the sentiment! Had it 10 years now. Not worth much so I’ll keep driving it until I can’t. Easy enough to work on as well.

Don’t mind me while I show it off a bit!

 

[TXCarGeek]

I appreciate the replies gentleman.

Did some more reading and found a couple more options aside from replacing the o-rings like TRAV mentioned.

Found this BMW part with some fuel line and the quick disconnect. Main problem with this is that I would need to have the other end crimped onto the fuel rail which I believe a local hose assembly shop might be able to do for me as I've had them to do similar work on my Mercedes W126 560SEL before.

I suppose I could pull the o-rings from this part assembly but it's not cheap...$80 for two o-rings doesn't sound amazing to me!

As you can see on this picture from ebay, the fuel rail side of the hose is crimped in place

 

[TXCarGeek]

Other option I identified is to do something like this on both the hard line to the fuel rail and the hard line that feeds it from the tank and fit some AN hose in the middle something like this:

 

[paulo57509]

Other option I identified is to do something like this on both the hard line to the fuel rail and the hard line that feeds it from the tank and fit some AN hose in the middle something like this:

View attachment 156685

That is a clean way to fix it. How does that adapter attach to the metal tube? Is it a compression fitting? I have had no luck getting these to seal properly. They work but they seep.

This is how I did the aftermarket transmission cooler on the Safari. The Earl's tube adapters were a bear to get sealed. I really had reef on on them to get them to stop seeping.

I'd like for info on that fitting. Tx

 

[TXCarGeek]

That is a clean way to fix it. How does that adapter attach to the metal tube? Is it a compression fitting? I have had no luck getting these to seal properly. They work but they seep.

This is how I did the aftermarket transmission cooler on the Safari. The Earl's tube adapters were a bear to get sealed. I really had reef on on them to get them to stop seeping.

I'd like for info on that fitting. Tx

View attachment 156706

I’m not sure how exactly that specific fitting seals up—I was wondering the same thing but I assume it must be compression. I found the original thread that picture came from just now so I’m going to see if they mention where they got the fittings from.

 

[TXCarGeek]

Update:

As TRAV suggested, I pulled out the o-rings from the quick disconnect. Pretty hard to manage. One ripped and the other came out in almost one piece but good enough to get an approximate size.

These are the sizes: correct me if I’m wrong but if I had to guess, I would say they’re likely 7mm ID, 11mm OD, 2mm thick

 

[NYEngineer]

MANY years ago, my brother and I were at our diesel shop on a Saturday afternoon. The auto repair shop in front of us was closed on Saturdays for religious beliefs. This young guy pulls in looking for the guys up front. He was driving an older BMW. He had it worked on up front and needed to know if it was ok to drive with this "slight leak" because he had a date in a few hours. We said they're not here but we'll take a look. He opens the hood and gasoline is spraying everywhere from the fuel pressure regulator. I said you absolutely should not be driving this. We went through our inventory of O rings but didn't have anything exactly right. Then my brother looked at this 2.2 Dodge engine he was hopping up for his daily driver and realizes the regulator was identical. We swapped that regulator on to his engine, using plenty of Murphy Oil Soap so not to damage the O ring. Sent him safely on his way.
That story always comes to mind when I think of fuel systems and O rings.

 

[TXCarGeek]

MANY years ago, my brother and I were at our diesel shop on a Saturday afternoon. The auto repair shop in front of us was closed on Saturdays for religious beliefs. This young guy pulls in looking for the guys up front. He was driving an older BMW. He had it worked on up front and needed to know if it was ok to drive with this "slight leak" because he had a date in a few hours. We said they're not here but we'll take a look. He opens the hood and gasoline is spraying everywhere from the fuel pressure regulator. I said you absolutely should not be driving this. We went through our inventory of O rings but didn't have anything exactly right. Then my brother looked at this 2.2 Dodge engine he was hopping up for his daily driver and realizes the regulator was identical. We swapped that regulator on to his engine, using plenty of Murphy Oil Soap so not to damage the O ring. Sent him safely on his way.
That story always comes to mind when I think of fuel systems and O rings.

Funny how things work out like that sometimes. Wonder if the guy tells the story today also.

 

[paulo57509]

I have found that for some reason, car manufacturers seldom use off-the-shelf sized o-rings.

Honda parts lists will show the o-ring dimension but they seldom match "standard" sizes. I usually end up here:

The O-Ring Store LLC, We make getting O-Rings easy!

Order O-Rings online Millions of AS568 O-Rings, Metric O-Rings and Hydraulic Seals Online. Live chat for O-Ring Sales and service. Our basic stock compound list includes over 30 o-ring compounds making us one of the most diverse O-Ring Suppplier in the Global O-Ring market.

www.theoringstore.com

 

[tcp71]

Update:

As TRAV suggested, I pulled out the o-rings from the quick disconnect. Pretty hard to manage. One ripped and the other came out in almost one piece but good enough to get an approximate size.

These are the sizes: correct me if I’m wrong but if I had to guess, I would say they’re likely 7mm ID, 11mm OD, 2mm thick

Choices on this page:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

These are readily available:

 

[NYEngineer]

Funny how things work out like that sometimes. Wonder if the guy tells the story today also.

I bet he does. He got my shop dog all excited and panicked and tried to run from him. I'm SURE he tells that part.

 

[The_Eric]

Update:

As TRAV suggested, I pulled out the o-rings from the quick disconnect. Pretty hard to manage. One ripped and the other came out in almost one piece but good enough to get an approximate size.

These are the sizes: correct me if I’m wrong but if I had to guess, I would say they’re likely 7mm ID, 11mm OD, 2mm thick

Viton 0-ring on Amazon