My brake car perform poorly.
Previously I have replace single layer servo with double layer servo.
But I seem it did not change anything.
Then I remember there is an aftermarket product (2nd picture) to increase vacuum for brake servo.
I use water bottle to replicate that product.
Connect a hose to the bottle end and the other hose connect to brake hose (connect after one way valve).
AAs a result, I can feel better brake performance and less use feet power to brake.
