Gas tank feed pipe shedding paint

Skip Newsom · 08-14-2019, 07:26 AM

I posted this situation on the NW forum and thought I should seek ideas from the greater Porsche community as well, I did some searches but did not see this issue crop up before.

I siphoned some gas out of my '72 using 3/8" rubber hose (I've done this a few times over the years) to my surprise I saw some fairly large flakes of very thin black paint in my gas can afterward.

My immediate concerns were where did it come from and what if any of it gets to my pump, filter etc. and plugs it up causing a stall or worse.

I knew I needed to pull the tank and get it cleaned as well as figure out where the paint came from.

Here's what came out of the tank

After pulling the tank and looking around inside it's in great condition after 47 years, it does look like a light coat of sediments on on the bottom, but no big issues, no rust and a good rinse should clean it.

I found where the paint came from!
the feed pipe from the fuel door to the tank is the culprit.
Nozzle side

Tank side

Now my question is what's the best way to clean the inside of a 2" curved metal pipe of any loose paint (besides replacing it)?

And should I just leave it bare metal or re-coat it with something that won't repeat this issue?

Skip Newsom · 11:26 AM

After considering the worst case scenario and hunting around I see our host has a replacement for $45...

Color me pleasantly shocked and pleased!
Pelican Parts $45 wealthier. (OK, Pelican got more than $45, I'm good with it!)

My plan is to pressure wash the tank, then soak in muriatic acid overnight, pressure wash again.
I'm replacing the fuel line fitting/screen assembly too(more $ than the pipe), clouds of dirt and whatever came out of mine while rinsing it in fuel.
I see a small tear in the outer jacket as well.
Also ordered gas fitting seals and the foam pipe to body seal.

I'd be surprised if this hasn't happened to others, I'm sure the fuel filter catches it the small bits, but the amount that came off the inside of the pipe was plenty to clog the system.

My advice for those with 46 year old or more 911's, next time you fill up take a look down your filler pipe with a flash light and see if paint has come off.

Trackrash · Trackrash's Garage

Wow, I didn't realize it was painted inside. Crap. Well, mine isn't flaking off YET.

Sebscst · 08-14-2019, 01:05 PM

Got to love ethanol.

BoxsterGT · 08-14-2019, 01:35 PM

I would recommend having it stripped of paint and zinc plating it.

No chance of ever peeling off. Can do many colors, but yellow zinc or black zinc would work.

Len

Skip Newsom · 08-14-2019, 07:38 PM

It was not ethanol, I'm careful to run pure gas in it.
I've sworn off siphoning gas from her ever again though.

Treating the gas tank as a one way only device, I would not think a rubber hose could take that much paint off!

Zink plating is an interesting idea, I'll bet a new one will last long enough I won't need to worry about it ever again :0

Skip Newsom · 08-14-2019, 07:44 PM

Oh man!!!!

I just checked my e-mail and saw this from our host:
We regret to inform you that we recently discovered the following Genuine part(s) have been discontinued and are No Longer Available (NLA):

911-201-051-00-OEM
FILLER NECK

At this time we do not have an alternate source for this part. If these were the only items purchased, we have cancelled and refunded your order. If there were other items purchased, they are still being processed and will ship as scheduled.

We are very sorry we are unable to fulfill your order as requested. Should you have any questions or concerns, please feel free to reply to this message or give us a call at 1-888-280-7799 and we will be happy to further assist you.

Guess I'm back to figuring out how to strip it... Hot tank?

Trackrash · Trackrash's Garage

I have siphoned gas out of my tank numerous times. There are scratches in the paint inside my neck, BTW, but no pealing.

You know the inside of the gas tank does not have any paint or coatings, so why would the filler neck be painted?

Skip Newsom · 08-15-2019, 06:49 AM

I'm sure the engineers at Porsche had their reasons, my thought is that since the feed pipe is empty 95% of the time it was painted with a fuel proof coating to prevent rust.