This is not a specific thirdgen question. But the other day I seen my girlfriends dad putting power steering fluid in his brake master cylinder. He thought that would fix his front brakes that just needed new pads and rotors. Could this type of fluid do any damage to the brake system. ie. the back drums are getting no fluid from the master cylinder to work. (you can turn them by hand when the brake pedal is pressed). The front brakes however work fine. When you first press on the brake pedal to stop the pedal is fine but after a few seconds it goes to the floor like they need bleed. However I have bleed the brakes many many times and are still getting no where. Any suggestion on if the power steering fluid could be making the master cylinder would be nice. thanks in advance

 

never heard of putting power steering fluid into the master cylinder before. what exactly would this accomplish? Have you checked the pads and lines?

 

The pads on the front are fine, and the pads on the back could be replaced but they are not so bad that they shouldn't work. All the lines from the master cylinder to the back brakes are fine.

 

well....they both flow through rubber so I don't think there is a problem with hose integrity, but brake fluid undergoes extensive testing (DOT) to serve a specific purpose. I would not ever use fluid for power steering in my brake system. Maybe I missed some info: why did he use it in the first place instead of brake fluid?


The reason the pedal is going all the way to the floor is during the later part of brake pedal travel is prob b/c he added it on top of whatever brake fluid was already in the line. So now he's got less compressible brake fluid near the caliper and more compressible fluid at the master. SO you get firm feel until a point and then its just mush b/c power steering fluid is worthless in a brake system.

Drain it all and start over.

 

Thanks Matthew91-Z28


You have enlightened me on the subject of brakes. And just to let you know the guy put brake fluid in the master cylinder because he's an idiot that knows nothing about cars and honestaly shouldn't be allowed to drive one. Thanks for all your Help on this one.

 

Most power steering fluid is more like oil, & brake fluid I would describe as more fluid like water.

I wouldn't think they would be compatible, & definitely wouldn't want to ride in that car.