tips on OM612 air in lines?

I searched the forums and write ups and couldn't find any "new" (to me) info on solutions to getting fuel to flow after changing fuel filter.
I've changed fuel filter probably 4-5 times before, and the FIRST time I had a hard time getting low pressure pump to draw fuel. I thought I knew what I was doing after that. Even after priming filter and checking o-rings and connections twice I still have nothing but air in my lines above the filter; several 40-60 second crank sessions. There is no fuel leaking from the sensor or drain, so I am assuming I'm sucking air from the fuel return or output connections.

I have something that should work, but I haven't applied it. Make a simple trap.

You'll need a two hole stopper, some tubing, a container, and a vacuum source.

Stoppers like this are available.



Use a short piece of tubing inserted into the stopper with a hose on the vacuum side. Use a longer tube inserted with hose for the fuel inlet side.

A quart oil container with a viewing level slot should work to catch the fuel before it gets to the short tube and then your vacuum source.

The fuel inlet line would be connected to the fuel hose proper after the filter, or maybe it would work to connect it to the water drain tap?

Because it's diesel, a shop vac could be used for vacuum, or a manual aspirator bulb may work. (Do not ever use a shop vac on gasoline.)



http://www.google.com/imgres?imgurl...a=X&ei=EAfQTYOcG4q_0AHgtuHlDQ&ved=0CGgQ9QEwCw

A bar type hose clamp or vise grips (carefully applied) could be used to keep from losing any prime when the apparatus is disconnected.



As I said, this should work to pull fuel up into your system. I have not actually tried it. Have fun. vic

Edit:
On second thought you might just be able to use an aspirator bulb and direct the output into a small container. Maybe a trap is overkill? vic

The removal and thorough inspection found the problem and fixed it.
The Hastings filter may have improper sized 0-ring. It fit on the return port fairly loose. I do not have a metric set of o-rings, so I added an R-07 o-ring around the shaft inside the return fuel fitting. This presses against the top of the port on the filter, adding a little extra seal. I did the same on the outlet port by placing another R-07 (I think) at the bottom of the port well on the filter that the clear fuel line fitting presses against. I remember having the same problem a year or two ago, also with a Hastings filter, and using the same shade-tree "fix".

It had been long enough that I forgot the lesson I learned: Don't use Hastings filter. Sorry, I didn't take pics to show what I did. I hope this posting helps others who are having air influx problems.

Here's what I do to re-establish prime:
I unhook the fuel line going OUT of the low pressure pump to the high pressure pump and suck from there with a mighty-vac. That brings a solid flow of fuel all the way up to and through the low pressure pump. Never took long to start after I did that.

surlyoldbill said:

The removal and thorough inspection found the problem and fixed it.
The Hastings filter may have improper sized 0-ring. It fit on the return port fairly loose. I do not have a metric set of o-rings, so I added an R-07 o-ring around the shaft inside the return fuel fitting. This presses against the top of the port on the filter, adding a little extra seal. I did the same on the outlet port by placing another R-07 (I think) at the bottom of the port well on the filter that the clear fuel line fitting presses against. I remember having the same problem a year or two ago, also with a Hastings filter, and using the same shade-tree "fix".

It had been long enough that I forgot the lesson I learned: Don't use Hastings filter. Sorry, I didn't take pics to show what I did. I hope this posting helps others who are having air influx problems.

Click to expand...

What's a Hastings filter?

talkinghorse43 said:

What's a Hastings filter?

Click to expand...

Brand

surlyoldbill said:

Brand

Click to expand...

Cheaper than the aftermarket ($17 w/o shipping) @ Europarts?

talkinghorse43 said:

Cheaper than the aftermarket ($17 w/o shipping) @ Europarts?

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$25 total at FLAPS