I done messed up everyone. and then messed up again. I just bought this 1994 mazda b4000 (ford ranger 4.0 6 cyl) and went to replace the power steering fluid. opened up the wrong reservoir and pulled out the fluid with a turkey baster. Proceeded to put power steering fluid in this reservoir. Thought I was all good now, so i drove to work and back today (roughly 80 miles) w/o issue. Got home and checked the oil when I realized that I had put that power steering fluid into the brake fluid reservoir. I proceeded to pull out all the fluid from there with a turkey baster and replace with DOT 3 brake fluid. I then tried to bleed the brakes starting with the rear right one. At first, fluid came out, but then stopped. Though I thought I was doing everything right to prevent air from getting into the line, I think somehow that air got into that line. I then tried to bleed the rear left brake and was unable to get any fluid to come out at all. I then bled the front two without any issue. As of right now, the back two brakes will not let out any fluid when I try to bleed them and the front two are running clear brake fluid without bubbles when I open up the calipers. When I drive it, the brakes are spongy but they still work. The ABS light is on. I have to get to work tomorrow and don't have any other option but to drive myself, so I plan to drive to work (40 miles) then go to the nearest auto shop and have my whole brake system flushed. I have read many different things saying, Dont drive it, Dont drive it", but is that really true? If the front brake lines are all good then Im not going to just lose my brakes rolling down the freeway tomorrow morning right? Will a flush be enough to clear up the whole issue of some power steering fluid that may still be in the rear lines?

 

Flushing will clear out the PS fluid no problem.

As to why the rears are messed up, i cant say, was the initial fluid brown/rusty? They might be blocked (nipples) try removing the whole nipple, will it then flow?


As to safety? can't say, i think they're supposed to be split front/rear, but a friends F150 lost all brakes after losing a a front caliper line.

 

Thanks for the reply, I did not realize the lines are split rear and front but that makes a lot of sense now. The initial fluid that did come out of the rear right line was super rusty, so maybe the line is blocked up further up because when I removed the whole nipple nothing came out still. this could be the same for the rear left because removing the whole nipple did not allow any fluid to come out there either. I am hoping I wont have to replace the master cylinder or any of the lines.

 

If the fluid that initially comes out is rusty, then most likely the caliper or piston is rusted on the inside.
The dust seals are probably gone so some water worked it's way in.

If you pull the drums off and inspect the cylinders by gently pulling back the dust boots. I'm betting that you'll find quite a bit of rust going on.

Get a friend to sit in the cab and start the engine.
Loosen the nipple off, and have your friend press the brake pedal down and hold it there while the nipple is loose.
MAKE SURE THAT YOUR FRIEND DOES NOT TAKE HIS FOOT OF THE BRAKE PEDAL WHILE THE BLEED NIPLE IS LOOSE.

So while his foot is still on the brake pedal, tighten up the nipple. With the nipple tight, new fluid will enter the system from the reservoir.
Keep an eye on the reservoir when doing this and top up as necessary.
When your friend presses on the pedal while the nipple is open, this will force the rusty brake fluid out and open up the bleed nipple.
If the bleed nipple itself is blocked, then that will have to be cleaned or replaced with a new one.