Well...thanks for replay...its been ages and i stil hawe not managed to fix that damn thing.
One thing is not clear to me...how oil comes down in pump when that 3.5mm bal is there?
Under the bal is a gasket and under gasket is a metal plate...so ball has not lot of space to move and make free way for oil...
anyway i found one 3mm ball in house and i will try it as soon is possible.