How do you know if you need to change your rotors and brake pads? I'm asking because when I step on my brakes,
my brake pedal goes all the way in and its hard to stop. I was thinking about changing my brake pads but decided
to be sure. Does this mean I have to change to a new rotors or pads? Please help. Thanks in advance,

 

If the pedal goes to the floor that means one of three things. you are either low on fluid, you have air in the lines, or you have excessive brake pad travel. Excessive travel is caused by lack of pad. Your rotors should be fine unless your car shakes in heavy braking which is caused by warped rotors.

 

Or your MC is shot...

but check those other things first.

 

If your brake pedal goes all the way to the ground, then you either have air in the line or bad master cylinder like what Martini said. Also take a look at your brake fluid level. You can check if your brake pad is worn just by removing the wheel and looking at the brake clipper from the side.
You can tell if the MC is going by pumping your brake when your car is off. With every pump your brake pedal should be getting stiffer. The less pumps it take to stiffen your pedal competely, the better condition your MC is in. When you pump your pedal enough till it can't go down anymore then press on it and hold it. Your pedal should not go down at all if it does then there is a leak.
If you believe there is air in the brake system then you have to bleed it. It is very easy. I'm not gonna go into detail about that, get a Helm manual.
Goodluck

 

I think its more than likely your master cylinder. First make sure you have enough brake fluid. if that checks out ok pump the brakes with the car off till it gets hard then hold. if it holds you got air in the lines and needs to be bled. if it drops you got a leak. If no signs of an external leak like brake lines, calipers, wheel cylinders, or Master cylinder it's an internal leak. Replace master cylinder if so.

MAKE SURE YOU BLEED THE SYSTEM WHEN ALL REPAIRS ARE MADE.


[Modified by BuddhaSiR, 1:28 AM 10/25/2001]

 

Thanks for all the useful replies. I checked the brake fluid level and it turns out that it was very low. So I bought brake fluid and poured some in there. After that, I took it for a spin and brake fluid level didn't go down at all. Even for like 3 days it still the same level. Also I pumped the brakes when the car was off and it did get stiffer as I pumped it and it does hold. So I assume there is no leak. Also how do I bleed the brakes? Thanks for all your help.