My brake pedal fads when engine is started

Hi,

It sounds as though the brake master cylinder has failed. However, first check to make sure there are no leaks at any of the brake lines and wheels.

Next, take a look through this link. It explains what happens when the brake pedal goes to the floor.

https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

If the link contains symptoms that mirror what you experience, chances are the master cylinder is bad.

To get you started, here is a link that explains in general how one is replaced. Make sure to bench bleed the new master cylinder prior to installation.

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

If you look at the attachments below, they provide the directions specific to your vehicle for replacement.

I hope this helps. Let me know if you have other questions.

Take care,

Joe

See pics below.