High pressure diesel fuel lines

[Gokartbandit69]

I’m a bus mechanic and work with Diesel engines all the time, you should never reuse high pressure fuel pipes because each time you tighten the pipe it distorts the end of the pipes.
This link explains why
https://www.delphiautoparts.com/usa/...injector-pipes

[Tannaton]

Originally Posted by Gokartbandit69

I’m a bus mechanic and work with Diesel engines all the time, you should never reuse high pressure fuel pipes because each time you tighten the pipe it distorts the end of the pipes.
This link explains why
https://www.delphiautoparts.com/usa/...injector-pipes

I don't think anyone is disputing that it is "best practice" to use new pipes but what many of us believe is that in reality if done carefully and pragmatically the risks are very small. Most of the distortion of the flange occurs the first time the pipe is tightened, subsequent times will depend on how tight and if the pipes are installed in the same positions.

Once a re-installation is checked carefully for leaks and good running, there's little to no risk of problems occurring later unless the system is disturbed again.

I absolutely get that working on the diesel engine of a bus or at a Volvo main dealer the pipes will be renewed to reduce the risk of any issues as far as is possible, but there's no reason why someone working on their own car shouldn't do it.

[cheshired5]

Originally Posted by Gokartbandit69

I’m a bus mechanic and work with Diesel engines all the time, you should never reuse high pressure fuel pipes because each time you tighten the pipe it distorts the end of the pipes.
This link explains why
https://www.delphiautoparts.com/usa/...injector-pipes

I get the textbook explanation but there's a substantial difference between multiple tightenings and one or two mechanically sympathetic reinstallations of pipework.
I and many others have never replaced or needed to replace HP pipes on many D5s but if someone is the type who would mash up a reused fitting, they'll also be the type to mash up a very expensive new fitting too.

[Gokartbandit69]

I can’t get the pics
But after several bus fires a bench test was done on Volvo high pressure fuel pipes. After removing and refitting to the correct torque setting 3 times.You could see how the pipes had been significantly weakened around the neck of the nut and on the ferrule.
I will see if I can get the pics without getting sacked lol