Mechanics

BRAKE PROBLEM

2004 Chevrolet Silverado • V8 2WD Automatic • 132,000 miles

I replaced my pads on my 2004 chevy silverado and bled the brakes. I know I did all this right. The brakes are fine until I turn the car on. Then the brakes go right to the floor like the system is full of air. I have 130K+ on this truck and hear that they were made with faulty master cylinders. I can change that very easily. My question is how do I know it is not the brake power booster unit. Is there a way to check the master cyl vs the power unit. Thanks for your help,
Mike
Avatar
Mike Desrosiers
August 21, 2011.



If you're not leaking anywhere-and is sinking to the floor-replace the master cylinder, its not coming from the booster


Rasmataz
Aug 21, 2011.
I have thoroughly checked for leaks (thinking that was the problem).
I will replace the master cyl and start from there.


Tiny
Mike Desrosiers
Aug 21, 2011.
I do have a question about bleeding the brakes on this truck. Should I try bleeding the brakes with the power on or with the truck running?


Tiny
Mike Desrosiers
Aug 21, 2011.
You can do both as you wish and see what happens


Rasmataz
Aug 21, 2011.
In your expert opinion, is it worth a try or just a waste of time?


Tiny
Mike Desrosiers
Aug 21, 2011.
Replace it


Rasmataz
Aug 21, 2011.
I ordered a new master cylinder from Autozone (they were the only ones that could get it for me the same day). I received it at 5: 30 pm Sunday night. After I bench bled the new master cylinder per the new manufacturer instructions, I installed the MC. I bled the brakes, and I have done many disc and drum brake jobs over the years for my family and I (and we are all still alive), and the same problem still exists. The brakes get hard when we are sitting there bleeding them, but once I start the engine, they go straight down to the floor I have checked thoroughly for leaks and have not found any. Since I have replaced the master cylinder (MC), it seems like the only choice left is the power booster. Yet, a problem like this sure seems like there is air somewhere in the lines. It seems like there is a possibility that there is some sort of leak that I am not able to detect. I am thinking that my next move is to take it to a brake shop and get the system vacuum bled. What are your thoughts with my problem?
Thanks,
Mike


Tiny
Mike Desrosiers
Aug 22, 2011.
Check if it has a hydroboost integrated the brake system


Rasmataz
Aug 22, 2011.
Monday 8am. I have checked, and there is no reference anywhere to a hydroboost.
I have also checked again for leaks and it looks good. If this is all happening when I start the car, it seems like the power unit is the only thing left to check. What is your opinion?


Tiny
Mike Desrosiers
Aug 22, 2011.
Okay-while engine is off -pump brakes a few times hold it in and start the vehicle the brake pedal should sink a little-did this happened if so -the booster is doing its job.


Rasmataz
Aug 22, 2011.