Captain_Slow

After reading the stories of fires caused by ruptured fuel lines and seeing photos of the ones that looked like they were one turn of the key away from bursting.... I decided to closely inspect mine. I had decided to replace all pressure lines with Greg Brown's hoses (the no soft hoses with clamps on barbed fittings argument is convincing) and everything else with Roger's kit with clamps.

Today I pulled the intake tubes and airbox and was surprised to find metal lines all shiny with gold cadmium and soft rubber outer sleeves over the pressed on hard plastic lines. No cracking anywhere. (I do have one new Porsche fuel hose..the cross over line running under the oil filler neck).

The hoses and cad plating look like 3 to 5 year old hoses on a typical car.

The car has 86K miles. It had spent most of it's early life in New York and had just 24K on it in 2004 when purchased by the PO. The PO then used the car as a daily driver until mid 2013. I think most of the miles were highway miles.

Since I can't SEE external reason to replace any of the hoses (in the engine bay), I'm left wondering about the condition of the plastic pressed on hoses (with rubber outer layer). Could they still be toast due to 26 years of exposure to gasoline?

I'm wondering if cars from hot climates are experiencing more of the cooked and cracked hoses, or cars with much higher miles (more heat soaking, possibly in slow traffic). I really expected to see at least the beginnings of checking and cracking. I expected the cadmium plated metal lines to be oxidized to gray.

Looking forward to all the comments that will help others who find their old lines look much better than expected.









The small U-shaped hose is shown in the mirror. I spent some time inspecting this hose from different angles with the mirror. Looks great.

19psi

I replaced mine at 45K miles. They looked brand new from the outside but the insides had seen better days.

Bertrand Daoust

I would take a close look and if everything looks good I would leave everything in place... For a while. Go there regularly to make sure everything is good.
You'll need to change those some day of course but if everything's good, no rush.

But that's me.

OTR18WHEELER

For whats it's worth, I am also on a learning curve with the 928 ownership, just 2 yrs in, my '85 was pretty much ALL original parts, even the plug wires and fuel lines etc. are still original, even just yesterday removed the MAF while I was in there for other stuff,and they dont look that bad, but my lines will be replaced before the car is on the ground. Although my car is just 3 yrs older than yours, your lines and wires appear to be much newer. If mine looked as good of condition as yours, I would not worry about immediate replacement. That being said, my flex plate is broken due to vibrations from a TT bearing and forward shaft clamp that went unchecked for 29 years.

Captain_Slow

OTR -
What happened to your flex plate is hard to comprehend. Have you checked your crank endplay? The dial gauge with magnetic base (separate items) from Harbor Freight is the best way to do it. I think I paid less than $30 without any discount coupons. I had put all projects on hold until completing the crank endplay check.

Your car looks great. I really like the color.

OTR18WHEELER

The cracks in the flex plate are rusty, and all the rust color you see in the pic is just powdery, it wipes of with a finger, so the cracks have been there for some time, only a small area near the center bolts show a fresh brake. the spline also shows fresh markings of a recent movement. The car always ran strong and launched slideways from a dead stop. 1 yr ago I replaced the oem 7" rears with s4 8"s with new rubber, and replaced the TB/WP at the same time. I believe the combination of aggresive launches with wider tread patch was too much for the weak link in the drive train. Too much force applied to an unchecked flex plate clamp was too much for the beast. The car still ran great before the teardown, Only after reading about pinch bolt/flex plate Thrust brearing failure did I check mine. I am confident by TBearing is fine, as there is almost no axial movement of the flywheel. literaly maybe as much as this > l

Captain_Slow

This > | is about right. Mine was 0.17mm. Even if you can't really see the movement, you should hear a soft thud of sound when you pry the flywheel forward, then rearward.

Chalkboss

My hoses looked good prior to pulling them off... once removed several had minute cracks and when I bent them they fell apart. The plastic inserts were quite brittle as well. Car was babied it's whole life in So Cal and kept in a garage, 85K miles when I changed them. Unless you know for sure they have been changed then I would do them. Not a hard job and then you can relax about it.

The Forgotten On

Everything on my 81 was original and looked good. As soon as I got it driving again every soft line began to slowly fail.

So I replaced the fuel lines,they looked good at first but they had cracks when I bent them and could have burst at any time because they were over 33 years old.

So if you do not know the age of your soft lines, replace them. That means all of them. Even the power steering pressure hose, as that can burst, spray ATF all over your hot exhaust manifold and catch fire.

Err to the side of caution when dealing with possible sources of fire under the hood of these cars.

Ad0911

Flexible fuel hoses wear on the inside more than on the outside! A fuel line can look ok on the outside but may look like a dried up riverbed with cracks due to all those gallons of fuel running through it. Also, fuel composition has changed in recent years. More ethanol in it means other components are extracted from the rubber/synthetic material. The result is a nice looking fuel line on the outside while being totally worn out on the inside.

M. Requin

I would like to reinforce the statements made in the last three posts. Mine "looked" fine, and the u-shaped line broke in half on the bench. Those lines are way too old to trust IMHO, no matter what they look like.

Alan

Err...?

But I agree this is one place where its hard to know the condition, and the risk could be high.

If you are really thinking to defer it - try this - buy one fuel hose and replace it - evaluate the one you took off, if its good you have a good reason to leave the rest for a bit - if not do all the rest.

Alan

Captain_Slow

Thanks all. I posted the thread because I think many who find hoses in what appears to be good condition will defer replacement. I was already thinking I should replace them anyway just because I think they are original. Alan, I like your suggestion. It's true about peace of mind...there is none until the old lines are replaced.

Hobibill

Quite possibly the smartest thing I've heard today and the best advice I've read on rennlist.

the flyin' scotsman

I would suggest that a car built in 1988 requires the fuel lines to be replaced just from the age status alone.

We know they fail, the cars catch fire and destroy completely. Heaven forbid anyone is trapped inside when theres a fire.

Change the hoses......all of them IMHO