Q: Is a leaky brake booster unsafe if fluid level is o.k.?

If your brake booster is leaking but your brake fluid level is full, your brake booster would be leaking vacuum. This would mean that your booster has a crack, the check valve is bad, or the hose that connects to the booster has a crack or hole in it. I would not recommend driving a vehicle very much that has a vacuum leak in the brake system. Without the vacuum assist that the brake booster provides the vehicle, it will be much more difficult to slow down and stop.

The check valve in the brake booster is also designed to allow up to two full power brake applications after the engine has been shut off. This is in case the engine dies on the highway and you need to stop your vehicle and pull over. Without the assistance of the brake booster, if for any reason your engine were do die due to problems it has, or even if you ran out of gas, this could be a dangerous situation. I would recommend having the brake booster problem repaired before driving the vehicle as it could potentially be unsafe to drive in its current condition. For an inspection, a certified technician from YourMechanic can come to your car’s location to diagnose the brake system.