Use of Banjo Fittings in Diesel Fuel systems

[KiwiME]

I've tried a couple of other forums with no response - hopefully the qusetion can be answered here:

A banjo fitting normally has the threads wetted by the media passing through the fitting.

What are the chances that when the fitting is loosened and tightened (without specifically flushing it) that debris from the (aluminum) threads may contaminate the system?

Comments appreciated.

 

[MikeHalloran]

Pretty close to 100 percent, I'd say, unless the aluminum is anodized.

I hate banjo fittings.





Mike Halloran
Pembroke Pines, FL, USA

 

[Artisi]

I guess that if you have to force the "bolt" of the banjo fitting into the fixed part of the "fitting" you stand a chance of creating some aluminium debris which can get into the system. It therefore comes down to correct assembly proceedures.

I don't hate banjo fittings, but consider they should be treated as they are designed be treated and not used to make up for poor pipe alignment etc.

Naresuan University
Phitsanulok
Thailand

 

[KiwiME]

Thanks both of you for the comments. Yes, Mike in my experience with a front brake hydraulic manifold I made for a motorcycle years ago when changing it from single to twin disk, I did find the steel banjo screws generated metalic debris off the bare aluminum threads every time I disturbed the fitting.

I've seen banjos used in older diesel fuel systems but they seem to be more rare now, replaced with quick-disconnect plastic. It could be just a matter of cost, but it's clear that with wetted threads banjos are a poor choice especially for the newer systems.