So my question is what items might need replacing? i know that i already need new front lines and my proportioning valve is leaking brake fluid little. Here are the symptoms, The other day i went about 2 miles to the gas station and i had used my brakes earlier but all of a sudden at a stop light i couldn't push in the brake pedal... I got it pushed down but it stayed down about halfway and wouldn't come up without encouragement. Yesterday I was laving my house and got down my driveway a ways without using the brakes yet but when i did stop to go out the gate my brake pedal stayed halfway in. I tried shutting off the truck and there was a whining noise coming from the engine compartment like it was bleeding off pressure from something to let my brakes pedal out again. I turned it back on the pedal did the same thing. I got it parked and put away but there is definently something sticking because it wont coast and i have to keep it at 2000rpm to keep it moving in first gear. Anyone have any ideas on what needs to be replaced? its been freezing here for the last week or so if that matters at all. Thanks guys, im quite stumped on this one.

 

Sounds like a brake booster vacuum leak. Get all that fixed soon, I wouldn't drive it anymore in that condition.

 

The trucks sitting untill i get it fixed. I thought thats what it sounded like but i wasnt sure.

 

What are you referring to as the proportioning valve? Everyone confuses the ABS valve for it. The proportioning valve is screwed to the master cylinder.

 

X2 on the booster. It is 2 chambers with vacuum on both sides to hold it neutral. When you brake the side toward the pedal opens to release vacuum and the vacuum on the other side makes it easier to press the pedal. When you release the vacuum returns to hold the pedal neutral again. If the valve is broken the pedal can be hard to depress or not return. So check your lines and listen for vacuum leaks but I'm betting on booster. Anytime you service breaks you should inspect the whole system and this is a good time to change the fluid. Water freezing in the fluid can cause similar symptoms.

 

The valve the lines go into before being directed to the wheels. Its on the fame. And i do think its the booster but ive been busy with school. Im going to check the vacume lines going into it first. Thanks guys