Fuel line back flow

Non return valves are not a cure for air leaks. Where old fuel lines are replaced and yet air leaks or back flow into the tank still occurs when the vehicle is left standing for a time, then back flow valves can help out in a short term fix in some cases. I have not had any problems leaving a backflow valve in the fuel line permanently.

The valves can be a bit hard to source but some diesel specialists locally can get them in.
I have posted a photo of two sizes in case that is of some help.

http://www.farmphoto.com/thread.aspx?mid=881543&cb=1289023523901#881543

Road vehicles often have a spin on filter in the line before the lift pump. If the seal on these is faulty then air can get in to allow back flow in some designs.

The valves make the system secure regarding back flow but still any such leak does need attention or air may be sucked into the pump.

easier to fit a small header tank above the injector pump that cures a world of potential fuel problems.

several years ago our neighour had a telehandler that was difficult to start first time in the morning.... i borrowed it to top some trees ... it fired instantly on easy start... just needed about 6 successive easystart starts before it had pulled the fuel through to carry on running... was fine for the rest of the day.... he didnt have it long beore flogging it on.

easy start is the invention of the devil and should only be used in an emergency

totally agree... only use it when the bxxxxxx wont start without it. if its a case of flatten the battery or start on the first kick over and get working , it gets used