I have great brake pressure until i start the engine then the pedal goes to the floor and have no brakes. what could be the problem?
1999 ford mustang
Have you done a brake job recently? or worked on the brakes at all? Have you checked the brake fluid level?
The master cylinder
Could be a brake lines, inspect your brake fluid and pads. I suggest to see a auto mechanic.
The problem may be that the brake fluid level is low or the pedal connection may be faulty. You should have your car checked out by a professional mechanic for proper fixing.
When you start the engine, the brake servo starts to work, making it easier to push the brake pedal. You have air in your brake system. If you haven't worked on them lately, then you have a leak. Time to overhaul the brakes, I would say.
You didn't bleed the brake system!!!!