I just installed a replacement high pressure fuel line on our 944, similar to the lindsey racing kit. Its the type where you cut the old hard line and use a compression bite fitting to transition between the old hard line and the new flexible line.

Anyway, I fixed the thing in place and tightened it down, tested it, and it leaked fuel everywhere. I tightened it down some more to the point where I started worrying I had cross threaded the fitting, because it was getting far tighter than I was comfortable with. Tested and it still leaked a bit.

Last try - I had a friend hold one of the wrenches from the top (this is on an early car with the lines under the brake booster) and I turned the other side from the bottom. We put everything we had into it (a point where I usually start hearing things snap) and got it to the point where it just wouldn't move anymore.

It seems to be holding now - no leaks. I'm concerned that I didn't install the lines properly and that they may leak in the future. Are they supposed to take a massive amount of torque to work the compression fitting? I am not exaggerating when I say the amount of torque I put into this thing is usually enough to break whatever bolt I am turning. Calibrated wrist felt something like 70-90 ft lbs, about what I'd use on a wheel lug.

 

Did you use metric (8mm and 10mm), or 5/16" and 3/8" fittings?

 

Metric. I bought the kit from Rennbay.

 

I had the same issues and fears about damaging the fittings. I went to "Rent a Gorilla" for help and finally got them tight enough.

 

Thanks for the confirmation, that helps put me at ease a bit. In my garage, I am the gorilla which gets me into trouble as often as it helps.

The car is still on stands so its difficult to really test, but I just went out and ran the fuel pump for a good 10 seconds or so and again no leaks. I think its good.