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View Full Version : Are the high pressure fuel lines re-useable ?


slowgsr
12-21-2016, 12:38 PM
The 6 hard lines, they never leaked. So I need to replace them? A friend of mine works on small diesel equipment and says they always replace them if they've been removed. Never heard that one with these vans though

lindenengineering
12-21-2016, 02:50 PM
As a rule NO.
But a caveat.
Some manufacturers do recommend such a replacement.
But not in this MB case!
However if you bend the pipe for any reason then YES---Why you might ask?
Well in short, the word is exfoliation of the pipe interior.
Briefly, minute metal fragments start to separate inside the pipe wall when the pipe is bent. In service the high pressure fuel flow tears off the fragments causing what is known as EXFOLIATION.

These minute fragments end up in the injector nozzle sac and in extreme situations cause the tip to sheer off as the needle pounds the fragments down resulting in injector hosing & possible cylinder bore wash conditions.

So going back to SOME manufacturers do recommend changing the pipe when disturbed due to the fact that they have service intervals recommending replacement. BUT not in MB's case as a rule.
Just treat them with care---A precision part remember.
Hope that explains
Dennis
Mechanic

CJPJ
12-21-2016, 09:09 PM
^
Common rail direct fuel injection is a direct fuel injection system for petrol and diesel engines.

On diesel engines, it features a high-pressure (over 1,000 bar or 100 MPa or 15,000 psi) fuel rail feeding individual solenoid valves, as opposed to a low-pressure fuel pump feeding unit injectors (or pump nozzles).

Third-generation common rail diesels now feature piezoelectric injectors for increased precision, with fuel pressures up to 3,000 bar (300 MPa; 44,000 psi).

slowgsr
12-21-2016, 11:01 PM
Thanks for the explaination. With everything else I've replaced, I'm going to replace these 6 lines.