I was driving my focus and stopped at a store when I got back on the road my pedal was soft and car was not even stopping. I checked and the brake fluid was gone, I filled it back up and found out I had to bleed the air out. I Have bled my brakes and have got it back on road but I feel like its not 100%. I have checked on the fluid level and its still full so my question is, Why was there no fluid that time and can it just get used up after years of not filling it or changing it? Because the fluid has been in it for some months now and has not got low. I'm worried I didn't fix the problem.Thanks
Brake fluid doesn't get used up, it has to go somewhere. One possibility is that your brake pads got worn down enough for the calipers to go in far enough to draw so much fluid from your reservoir that that the level dropped low enough to introduce air into the system. If that is the case then I'd suggest replacing those pads and giving the system a thorough bleed. Keep in mind that when you push the calipers back out the fluid will go back into your reservoir, and as you've filled it you could overflow. Use a syringe to remove some fluid so it doesn't happen.
It's also possible that you have a leak in your braking system somewhere:
- master cylinder seals have gone
- brake line leaking or badly connected
- brake caliper seals degraded
I would go over the system with a fine tooth comb; small problems have a tendency to become big ones, and in this case could leave you without brakes at a critical time, which is bad™.