You probably will not suspect that you have any problem with your brakes unless you notice a change. Perhaps your pedal feels different when you press on it, or maybe you notice that the fluid is low and you have just filled it. Your issue could be worn out pads on your brakes, or a leak in your system. If you have filled it and it goes low again soon after, then you should go to a mechanic to see what they think.
Having leaky brakes is nothing to mess with. Before you take your vehicle in you might want to test your car to see where a possible leak could be originating. If you park your car on a flat area and then look under the car to see where fluid has come out, that may help you to know where the leak is. This might save you some money on brake repair, because you can mention it to the mechanic, and it might save time.
The system for your brakes has a cylinder at its center from which the fluid flows to the four wheel areas to keep them working correctly. If fluid is not going where it needs to go, then your brakes will not work, and it could be very dangerous. Not all leaks will be as dangerous as others, but if you notice that your pedal feels strange under your foot and will not build pressure when you pump it, then you need immediate attention for your vehicle.
One reason that might be a possibility for why your brakes are leaking is the bleeder valves or bolts. This is not a serious issue. If you recently had maintenance then it is possible the mechanic neglected to close or tighten a valve. To remedy this, you will want to call the place where you had taken your vehicle and tell them what happened. They should happily tighten the problem without charging you anymore.
Whatever the reason that you think your brakes to be leaking, you will want to take your vehicle to a mechanic for brake repair. There is no reason to take the risk of endangering you or others by not getting your vehicle checked out.
If you are short on money, then you will want to comparison shop for brake repair mechanics. If you know a little of what is likely wrong with your vehicle then you may be able to give a few local brake repair shops a call to see what they charge per hour as well as for the parts that you might need for your possible issue. Of course they will not be able to give you a definitive estimate, but they may be able to give you an approximate one.
Knowing about how your brakes work will definitely help you as you try to diagnose your vehicle. Self-diagnosing is not a bad thing as long as you do not try to take the work into your own hands. You may diagnose wrongly, but at least you can be knowledgeable with the mechanics that will look at your vehicle.
