[Vwdiesel] Bend-it...Bend-it...

[James Hansen]

Well, I would suspect that the design of the lines is such that they are
intended to last the life of the car if everything stays just like it was
intended.. clamps on, lines loosened to move pump etc...  The area of
highest stress is where the pipe gets thinner just after the flared end.
Biggest problem with the pipes is vibration in the long run- which the flat
clamps are to address. I've seen where the clamps get loose, followed by
line fracture soon after.  This was on bigger motors however... the short
little VW lines are pretty good as fat as not vibrating goes.

I can't see the lines being hardened. Too expensive on a cheap part, and
surface hardness doesn't always translate into a stronger part either. It
can make it fail sooner.   I would think they would last the longest if
properly annealed so they would be soft, and more elastic.

That said, I have never had a VW line fail... have lost a couple on other
farm stuff mostly from vibration and some little invisible insignificant
trinket rubbing against the line until it is worn through.


> James
> Can you clarify for me if it is simply repeat bending fatigue
> that may cause failure in the mild steel fuel lines rather than
> any 'aquired' brittleness; implying a hardening...else the
> 'belled' ends would be less prone to this grooving problem...
> Which makes me think a slight case hardening of the ends of the
> lines might negate this
>

---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.647 / Virus Database: 414 - Release Date: 03/29/2004