Air in the fuel supply help

[UB_Bomber]

Been tinkering on the ol 69 m35 with the ld465. Been going through the fuel system and found air in the line after the booster pump. Supply line is full. All new fuel filters. Tank pump is pumping. I have not done a flow check. Just ran the line back into the fuel tank and it had an impressive flow. At first I figured it was just residual air from the filter changes but after 30 min of high idle it is still pumping air. My next step is it put a pressure gage on the fuel filters unless if I am missing something obvious. Pulled all the supply line fitting and inspected. Ran the tank pump for a while looking all over for leaks. Think I need to rebuild the booster pump? Possibly pulling air from the crank case?

Thank you guys. I am seriously scratching my head.

 

[frank8003]

Is the hose on in tank fuel pump failing, leaking air in?
How much fuel in the tank?

 

[Welder1]

Been tinkering on the ol 69 m35 with the ld465. Been going through the fuel system and found air in the line after the booster pump. Supply line is full. All new fuel filters. Tank pump is pumping. I have not done a flow check. Just ran the line back into the fuel tank and it had an impressive flow. At first I figured it was just residual air from the filter changes but after 30 min of high idle it is still pumping air. My next step is it put a pressure gage on the fuel filters unless if I am missing something obvious. Pulled all the supply line fitting and inspected. Ran the tank pump for a while looking all over for leaks. Think I need to rebuild the booster pump? Possibly pulling air from the crank case?

Thank you guys. I am seriously scratching my head.

I would pull the in tank pump and inspect the pump and hose.

 

[UB_Bomber]

I pulled the in tank pump but maybe I missed a nick in the line. Tank is just over 1/4 tank. Thank you all.

 

[Barrman]

Check around your bleed screw at the top of the secondary filters. I had one crack there and let air in once. The in tank pump is my guess as well by the way.