fuel line questions

[rustyescott]

i'm in process of replaceing my return lines , and i here people advise on the fuel line to ip to use a 12" piece of clear tubing for a air ck line. is this tubing diesel rated and if so why not use thru the whole return line system?
also why do they use a rubber olieve on the hard incoming fuel lines instead of a flair fitting?

 

[icanfixall]

I believe the olives are used for vibration protection and thats about all. Not sure but a thought.. As for the clear line... Thats only something used to find a possible air leak. Its used between the filter out side to the injection pump inlet end. What is done is that hard line is cut and then a piece of rubber clear line is installed there. Your only going to see air if the filter, lift pump or lines from the tanks have a leak. Nothing will be seen if the air leak is in the return lines. BTW that return line off the filter heads on any 7.3 is not fuel return to the filter. Thats there to allow trapped air in the filter head to return to the fuel tanks via the injecter return line system. Some have made the comments that the filter return is from the injecter return lines... So now ya all know...

 

[rustyescott]

ok thanks

 

[Arborigine]

I am replacing my lines, using 3/8 copper for the feed lines. They don't make 5/16 copper for the returns, so i am clipping off the ends of the gray plastic tubing and connecting it with fuel hose and clamps. Since it is under pressure instead of suction, air leaks are irrelevant and any seepage will become evident.

 

[duke3478]

... it is under pressure instead of suction, air leaks are irrelevant...

I wish it were that easy...:/

You may find that air leaks make quite a difference, feed or return (pressure or vacuum) side. It's just the way these engines work.

 

[jim_22]

I agree with Aborigine: fuel pressure trumps air leaks. Sucking on the other hand just plain sucks.