Had an identical issue on an 88 silverado(never figured it out) I have a 99 chevy malibu that doesnt want to stop( a lot of foot) however on the silverado I replaced everything and it still didnt want to(never figured it out). The Malibu evrything has been replaced but the brake booster and the master cylinder. Am I missing something with chevy brakes that I cant get them to stop? Trying to get some feedback before I replace the booster and master cylinder so I dont throw another 200 dollars at another chevy that wont fix the issue.
I also should mention when I got this car for repair the driverside front pads were almost worn out and the passenger side looked like they had been on the car for maybe a month almost looked new replaced calipers and hoses. This car also is all over the internet with braking issues.
It sounds like the proportioning valve is faulty. These chevys have a valve or set of valves that equalize the fluid pressure to the four cylinders.
Also just found out that when I pump the brakes the pressure isnt building like it should the pedal drops everytime. I keep thinking booster.
This right here makes me think you have a seized front brake caliper on the right.
I would recommend having both front calipers replaced at the same time, since rebuilt ones are fairly cheap, and if you can do the work yourself, its an even less expensive issue.
Might be worth while to replace the rotors, pads, and front brake lines all in one shot, just so the braking capabilities of the front is even across the front end.
BC.
“The Malibu everything has been replaced but the brake booster and the master cylinder”
The Haynes manual has a procedure for testing the brake booster. The pedal dropping sounds like a master cylinder or other problem.
Is this a low pedal issue or a hard pedal issue? If it’s a low pedal issue, you may just need to adjust the rear brakes. I have seen many DIY’ers make this mistake, and a low pedal seems to be more profound on Chevys than just about anything else on the road. Adjusting brakes is sort of an art form, albeit an easy one to pick up once you’ve been shown how and done it a few times. If you don’t know how to do it, most shops will do it for you for around $30-40.
If it has the ABS valve body on/near the master cyclinder, they are notorious for tearing up o-rings allowing fluid to bypass internally and not go to the brakes. If it doesn’t have ABS, there are one or two proportioning valves, front/rear and possibly rear adjusted by load level. Wiping out the left front pads is common as the front/rear proportioning valve fails more than it works allowing the left front to take most all the loading on stop or not release completely.
Another, and the most common issue, is improper bleeding of the system. Despite the crap printed on the instructions that come with the master cylinder, the cyclinder must be bench-bled using feedback hoses. When it’s installed on the vehicle, it must be bled again at the connection ports and post ABS valve body before you even consider going to the wheel cylinders. These systems must also be vacuum bled then dynamically bled because they contain numerous air traps.
The proportioning valves are often sealed so they can’t be disassembled for cleaning/repair and if you purchase new valves, be sure to inspect them before installing because I’ve gone through more than a dozen in one store standing at the counter because they were contaminated with metal/plastic shavings.
Last but not least are the steel lines running from the master cylinder to the wheel/axle hoses. With this being a '99, that’s plenty of time for the internals of the lines to become rusted shut or almost shut. Only way to test the hard lines is to disconnect both ends, drain and check fluid flow through them (compressed air will pass obstructions that greatly impede fluid movement so blowing through them with compressed air is not an acceptable test. For the cost of new hard lines, it’s usually best to just replace them and be done with it.