I have a question concerning my brakes (they used to work).. When the truck is not running and i pump the brakes they do get tight and when i start the engine there is no brake pressure in the brakes after it started.. i pump them when the truck is running and still no pressure, when im driving the truck i have to pratically put the brake to the floor to stop what is the problem? Yes i did bleed the brakes and filled it with more brake fluid. Do i need new brakes or is it the master cylinder.. thanks

 

Oh yea another thing, after i start driving with the brake problems the brake light turns on and after i stop and pump it for a minute it turns off but still no brakes, drive again and light is back on...

 

Have you checked to make sure there is no leaks in the brake hydraulic system? You need to remove all four wheels and check the rubber lines and rear wheel cylinders. If everything is good and dry, it is most likely the master cylinder. The hydraulic pressure can bypass the seals internally in the master cylinder and have no signs of external leakage.

The best way to check the master cyl is when the truck is off and you know there are no visible leaks. What to do...pump the brakes until you get a pedal, now hold steady pressure on the pedal and see if it goes down slowly. If it does, it is a master cyl.

 

Not to sound stupid or anything. Could you tell me where the master cylinder is, so when i replace it i wont have to search all day to find where it is located.
Thank you nate..

 

The master cylinder is where you put the brake fluid. The brake fluid reservoir is connected to the master cylinder.