'74 Targa gas leak rightside front axle

klober23 · klober23's Garage

My friend just sent me a message and told me he has gas "pouring out of the front right side under axle" on his 1974 Targa. Thoughts? He said the fuel pump ran for awhile before it started leaking. Unfortunately I am unable to go check it out in person today, so thought I would toss it out to the community.

Thanks in advance.

manbridge 74 · 06-23-2013, 06:51 PM

Right front would indicate leaky tank perhaps. Unless pump was relocated to the front and there is some high pressure spray to the right.

Charles Freeborn · Charles Freeborn's Garage

I had a leak in front that was the rubber hose from tank to rigid line that runs down the tunnel, but it was more centered than to the right.
Stinker to replace - way easy when the steering rack is out.
-C

fintstone · fintstone's Garage

Quote:

Originally Posted by Charles Freeborn

I had a leak in front that was the rubber hose from tank to rigid line that runs down the tunnel, but it was more centered than to the right.
Stinker to replace - way easy when the steering rack is out.
-C

I would guess the same.

HarryD · 06-23-2013, 07:38 PM

Are you sure you do not mean the DRIVER side of the car? There are no fuel lines on the Passenger side. If it is the driver side, you have a failed vapor recovery line or tank. You should be able to see it.

fintstone · fintstone's Garage

When when that soft line to the tank breaks or comes off...the fuel could go either direction...

klober23 · klober23's Garage

I wanted to follow up on this as I finally had a chance to tear into the car. The culprit was the output hose right at the fuel pump. It was indeed running along the plate to the right side of the car as was suggested above. Although I cannot see anything physically wrong with the hose where its leaking, its enough under pressure to strongly seep out. I assume its suitable to replace this short span of rubber hose with one from my local parts store?

Also, while I had everything exposed I noticed one of the boots on the front passenger side axle is ripped in two. The car has 45K original miles, do I have to purchase a kit and do the entire thing if wear looks good?

Thanks again

porwolf · 09-23-2013, 09:42 PM

Right side? Does that mean right side looking at the car from the front?

p911dad · p911dad's Garage

Klober, I have done this repair on our '84 Carrera. There are 2 plastic hard lines running from the fuel pump and tank to the engine, a feed line and a return line. The problem comes when the short rubber flexible portions that connect the plastic lines (they run through the tunnel) to the fuel pump and tank deteriorate. The rubber parts are factory crimped onto the plastic lines, and while it is possible to rig up a fix using locally sourced rubber hose, it will not be as safe, especially if you use hose clamps to attach them together. Several folks on this board have had the connecting parts made up at a hose shop, search it out. Remember, this is gasoline under pressure. Each entire line is one factory unit and really should be replaced as a unit. Our host carries these parts. For me, the job took the entire day and is a stinker for sure.
If you do decide to pull the lines, one hint is to attach strong twine to each line before pulling them to make it easier to thread them back through the tunnel. There's lots of stuff in the tunnel so it's tight.
In regards to the steering rack boots, they need to be intact as they keep dirt out of the steering rack itself, so replace them if you can. Good luck, Glenn

klober23 · klober23's Garage

Glenn,

Thanks for the great info, I appreciate it. I can tell the fuel lines have been reworked in the past, as someone did not take the time to remove one of the old hoses that run above the axle through the body clip. I have a exploded view of the fuel system, but plan to search to see some real images of how everything should be crimped on etc. Thanks again!

BoxsterGT · 09:54 AM

Tell us more about the fuel system in your friend's 74 Targa. What part of the system has been upgraded? Can you post photos?

A 74 911 originally came with a rear mounted fuel pump and white nylon tubes through the tunnel. These tunnel lines were used for one year only, and for good reason.

Porsche changed to the black Polyamid tubes through the tunnel in 1975 and has used this type of tube on all models since.

The original white nylon tube turns brown over time and gets hard & brittle and cracks under slight movement. (Shown at right center of photo below)

These original tubes are a catastrophic failure waiting to happen.

Len

BoxsterGT · 09-24-2013, 07:25 AM

A front view of the original 74 911 white (now brown) Nylon lines......

With the factory rear fuel pump this is all low pressure, so the hoses were slipped on over the tubes and clamped with a common hose clamp.

If this 74 has been upgraded its important to know how this was done. If the pump is up front, the system is now high pressure, and proper Fuel Injection Hose and fittings must be used throughout.

Len

p911dad · p911dad's Garage

Great piece of knowledge Len, I didn't know the lines changed that late. By the way, the fuel line set you made up for me for the engine worked out perfect, no problems. Glenn

klober23 · klober23's Garage

Very good info.. Yes there is a front mounted fuel pump. My goal at the moment is to replace the fuel line and allow it to run a few minutes so I can diagnose some oil leaks. I would like to redo the fuel system and fix oil leaks over the winter.

klober23 · klober23's Garage

Len,

In your experience would it be worth it to update to a new high pressure system including appropriate hoses, or go back to the original low pressure system? What is more desired as far as resale is concerned?

I have only briefly worked on the car, enough to find the leaky hose. It appears to have the brown lines (through the tunnel), although their condition is a clear yellow of sorts. The front mounted pump is now attached to the plate that covers the front axle. All of the hoses are held on with a common hose clamp, although due to the low mileage on the car, and the history I do know, this modification was done years ago.

Please see attached pics, they are not the best as I was planning on just using them for my quick reference, but you will get the idea I am sure.

Thanks
Jesse

klober23 · klober23's Garage

A pic of the car just for fun

BoxsterGT · 09-27-2013, 04:37 AM

This 911 is now 40 years young, and the original fuel system is way beyond the point of saving. No matter where the pump is located you must go through the entire system if you want peace of mind.

It appears the current leak is here............

where the hose is dark at the pump end.

Hope this helps.

Len at Autosportengineering dot com

BoxsterGT · 09-28-2013, 12:30 AM

Jesse- The fuel pressures for these models run as high as 60-70 psi, so this is nothing to take chances with. It looks like the "U" bend hardline has the hoses slipped over it with common hose clamps.

Can you show a photo of the fuel tank connections please? The typical 74 911 fuel tank has 8mm & 10mm OD tubes. The inlet to the fuel pump is 12mm OD. The hose appears to be 12mm ID. This is not a match at the tank....?????

Len

BoxsterGT · 10-03-2013, 11:04 PM

Status???

klober23 · klober23's Garage

Len,

I can get some more pictures for you this weekend as I will be around the cars. I did get the leaks fixed! After fixing the front, one sprung at the engine where the main hose comes into the engine compartment and divides off. I made a new line that will not fail. After a few test starts, I took the car for a 15 mile drive and it ran like a champ. However, I feel like the car struggles at an idle. Since this car has been sitting and I have never drove it previous to the fuel leak, I do not know if this was an existing issue or not. The car seems to idle around 400-500 rpm, but it seems like it may need a touch more. Any thoughts?