|
Is it leaking equally across both sides of the reservoir? If not, that helps narrow it down - if it drops only in the front half of the reservoir the leak is in the rear braking system, and vice-versa.
If it's leaking down equally, and you're not seeing any fluid anywhere, then the odds are pretty strong that the seal on the end of the master cylinder that is inside the brake booster is leaking. To check this you'll loosen the two nuts that hold the master cylinder to the brake booster and pull it forward to see if you can spot any wetness inside.
Note that there is a rubber seal ring between the master cylinder and brake booster that is there to keep air out/vacuum in. Make sure this gets re-seated properly or you'll have a vacuum leak and hard brakes.
|