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Bleeding primary fuel filter


DShK

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Hi, pardon what is a fairly basic question. I am just completing the first service I've done on my 2LW. The last thing I did was change the primary fuel filter (CAV type). The video I watched on doing this showed a bolt which you undid, pumped fuel through until the bubbles in the overflowing fuel subsided. When I use my lift pump to pull fuel through, I am not getting any overflowing fuel. I think the fuel is circulating as it should as I believe I can hear the fuel feeding back into the tank (and there does seem to be fuel in the filter). Doing some more reading and research, other engines people may bleed at the second filter. It seems gardners with a lift pump don't have a way to do that as air is automatically syphoned off here. 

 

So my question is, through pulling fuel up through the lift pump, have I bled the system effectively? I don't quite understand why fuel isn't overflowing the filter as it should. I know the second filter should syphon off any air, but my understanding is air between the first and second can wreck the lift pump. Holding off on trying to start the engine just in case!

 

Anyone able to offer an insight here? Thanks!

 

Edit: video I originally watched, timestamped to show what I mean. 

 

Edited by DShK
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Your primary filter is on the suction side of the pump so you wont get any fuel to bleed out of the filter.

Up to a point the system will self bleed as there is a return to tank from the on engine secondary filter. 

To manually bleed out the system there are  2 bleed points on the injection pump. one either end facing out at 45 deg just below the top of the pump where the sprayer pipes are attached.

The one in the video is on the delivery side of the lift pump

 

image.jpeg.fdbc091211b50623e8ee9974bbe9ab0f.jpeg

Edited by Split Pin
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On 20/11/2022 at 18:15, Split Pin said:

Your primary filter is on the suction side of the pump so you wont get any fuel to bleed out of the filter.

Up to a point the system will self bleed as there is a return to tank from the on engine secondary filter. 

To manually bleed out the system there are  2 bleed points on the injection pump. one either end facing out at 45 deg just below the top of the pump where the sprayer pipes are attached.

The one in the video is on the delivery side of the lift pump

 

image.jpeg.fdbc091211b50623e8ee9974bbe9ab0f.jpeg

That makes a lot of sense! Thank you. I did try the injector pump bleed point but you do kind of get fuel everywhere. I'll have to see if I can come up with a way to catch it.

12 hours ago, john.k said:

You may have the lift pump plunger on the cam lobe ,which will reduce or stop fuel flow.

Yeah I had this happen at first, I found a comment on here pointing it out, it helped a lot. Thanks!

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