My brake pedal goes all the way to the floor - 1987 Nissan Pickup

Brake pedal goes to the floor? When does it happen. That is the most important piece of information. Most brake systems are power assisted via vacuum from the engine. Your brake booster is what makes the "power assist" work. There are some specific times when you will feel your brake pedal "fade" to the floor and it is normal due to the cycle of the brake components operation.If your brake pedal goes to the floor every time you step on it, stop driving and get to a repair facility! If the pedal is working when driving and the vehicle seems to be working as it always has, then chances are there is no concern. To be on the safe side, have it checked the next time you are in for any other type of service.There is a sensor inside most brake reservoirs that activates the indicator light in your instrument cluster when the level is lower than it should be. As your brake pads wear down, the system requires more fluid so the level at the reservoir drops setting the light. Same thing if there is a leak. The fluid level drops and the light goes on. This brake fluid leak would most likely be combined with a spongy pedal or a pedal fade every time you step on the brakes. A leak would also almost always have a wet area around the leak. Sometimes the leak can be internal to a part of the car you cannot see, so don't count on it.One easy way to check most brake boosters and the brake system for leaks is to turn the vehicle off and pump the brake pedal. Every time you depress the pedal you should feel the pedal "height" come up and the pedal get harder. After a few firm pumps of the pedal, hold it down. Leave pressure on the pedal for 20 seconds or so. Does the pedal move slowly (or quickly) to the floor? If so then there is a leak somewhere in the system. Keeping pressure on the brake pedal, start the vehicle. Does the pedal no drop? It should. That is the power assisted vacuum kicking in as the engine starts to run.The bottom line is that we are talking about your brakes. Your life, your passengers lives and the lives of others on the road around you depends on that system working properly. If you have any doubts, or feel uncomfortable, take it in to have it looked at. Know specifically what it is doing so that you can have your repair facility look at what you are feeling and tell you if