Brake Problem on a 97 GMC K1500 Sierra SLT

[lodihoseman]

I'm not positive on a Chevy, but my Ford diesel has a vacuum pump that runs everything that needs vacuum. A diesel engine doesn't create vacuum on its own as the speed of the engine is regulated by the amount of fuel given to the motor, where a gasoline engine is regulated by the amount of air supplied. There is no restriction to the air supply on a diesel, which doesn't provide any vacuum. On a gas engine you would know immediately if you weren't providing enough vacuum as the engine would not run properly, but a diesel engine won't give you that indication. I would look there for your issue. Vacuum pump, or some of the lines from the vacuum pump.

[lodihoseman]

I should have mentioned, the brake booster uses vacuum to boost the brakes.

[Marry Parker]

I've had mine on a Chevrolet K1500 for a year and been happy with them. Luk Schaffer makes a nice slotted cross drilled rotor (this may help keep them cool and prohibit warping) for not a ton of money. I think they're called Black XD Series. Tell him to make sure that his calipers aren't frozen when installing new pads or rotors, better yet replace them or rebuild them if in doubt. This will help to insure longer life and no rotor warping.

[Dada1998]

I have a 97 GMC Sierra 1500 and I got it with the brakes bad but I’ve replaced the master cylinder brand new the wheel cylinders in the back are both brand new pads are brand new brake booster is used but I know it works still. I’ve messed with it for days and can’t figure out what it could be! Does anyone have any ideas?My check emergency brake lights comes on and off when applying pressure to the brakes. I have brakes after I apply to the brake about 80% down to the floor but it barley wants to stop. I need suggestions please 

[John 2012]

I am stuck. I have changed out master Cylinder, brake booster, fluid reservoir, pads cylinders, drums, everything I know to change out besides the metal lines and I still don’t have a solid pedal. What else can I change to make it better? 

[riverbanks]

Does pumping the brake pedal make it better?