How much pressure can car brakes take?

Question

Is the brake system supposed to support as much pressure as you can physically (with your foot) give it? I would think yes, but I'm curious if there is a specification of some kind or even if its possible to do damage.

My recent experience that lead to the question...

I was trying to sell an old used car I've had for a couple years which (i thought) was in good working order. The potential buyer was checking things out and pushed really hard on the brake pedal. We heard a pop and the pedal went to the floor. I look under the car and sure enough there's a puddle of fluid. The brake line along the wheel well rusted through.

Answer 1

When my car was just about 10 years old, I was braking VERY hard (hardest I'd ever pushed on the brake pedal) coming off a straight into a sharp 90 left and I heard/felt a soft "pop". The brake pedal dropped even lower and I lost a small amount of braking capacity. Turns out one of the seals in the master cylinder blew out. Fortunately they've been building them with an extra seal for redundancy (albeit at slightly reduced capacity) since sometime in the 60's or 70's... :-)

I have no idea what it's tested to, but as it ages, it will lose capacity. The harder you push, the closer you get to those (unknown) limits. The more often you press hard, the more you're weakening those parts...

Answer 2

Short answer: Yes, braking hard in an emergency would be.... hindered by losing the brakes. Long answer: It is very much a case by case basis. The short answer is what it is "suppose" to do. In reality, it depends on the age, condition and quality of parts. For instance, a brake-line with one of those metal weaves on it I would suspect would be able to take some serious pressure.

Answer 3

Manufacturer limits the move of the pedal. You can test it with breaks unattached - the pedals will freely move only until a stop.

I assume that manufacturer plans the system in such a way that you can't possibly push the pedal any further than the braking-system could handle without it giving up. The breaks pedal should handle any amount of pressure that is considered normal for a adult driver in good shape. That is a good test though - you would not like to discover you breaks fail in an emergency-braking where you don't have spare time to think about "am I pushing too hard now?".