about p38 2.5dt fuel pump

since weeks I have trouble related to difficult engine start. Long seconds of starter use without fuel injection and yesterday afternoon after an engine shutdown on driving down a mountain (while changing gears), I understood : there is an air leak on my fuel pump system, so I filled my tank and any problem dissappeared instantly ! Therefore i feel sure to say that there is a leak somewhere on the bottom of the suction system and tghat a simple solution is to keep at least 20-25 lkit fuel in the tank. Wathever this is fairly good for avoiding the suctions of various dust, mud or water drops.
in case somebody is experienced whith this behaviour of the bmw fuel feeding pump and knows how it can cheaply be fixed..
Wathever I can use my 80,000 miles p38 with leaving some 20-more lit in the tank. Cheap repair isn't it !

after two years using my P-38, I am starting to understand some whys and hows.

A new pump is £120, fitting it is a DIY job, otherwise factor in labour costs of 2-3 hours. If I drove my RR in the Alps I want it to be in perfect condition!

There is no suction system on the pump, there's no pick-up pipe, if it doesn't deliver fuel its because it isn't working.