The hyroboost started seeping and making a mess up under the brake system reservoir. I let it go until I could actually see the leakage on the driveway. When I had to put a can of DOT 3 fluid in the system, I decided to let the dealer have it for repair/replacement of the hydroboost. Never had any indications of the problem in braking performance. The repair would have cost somewhere around a thousand dollars without the extended warranty.