On low speed or idle my brakes are very hard and feels like the engine is not running. On high speed it is OK (not excellent)
On depressing the pedal on start up there is a slight difference but really slight.
I have checked the non return on the servo and is working perfect.
With the engine running and holding my thumb over the vacuum pipe there is not a lot of vacuum.
It feels like sucking and releasing.
There is a hissing sound from the servo unit when the engine is not running and applying pressure to the brake pedal.
Question: Is it the servo unit or vacuum pump.
The truck:Disco 1 300 TDi 1997 manual (300 K)
The vacuum pump is a sealed unit: Can it be repaired or serviced?
(Just for info: I am stranded in Mozambique and service and repair shops is not around the corner ( I need to make a "Plano de Afriqua)