losing prime on fuel filters

[old mack man]

Hello I have a 1990 5ton. bmy and I keep losing the prime after parked a few days what could cause that if I top off the filters and pump hand primer crack injector line it will start any ideas

 

[juanprado]

Check fuel line. Rubber hose notorious for degrading and sucking in air.

 

[old mack man]

Thanks you I checked all hoses and added a few hose clamps on ends I will know in a few days is there any check values that could be leaking back to tank

 

[Jbulach]

Two in the lift pump and one in the outlet of the Injection pump.