Power steering fluid in brake reservoir

Tiny
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  • 2007 MITSUBISHI OUTLANDER
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  • 84,000 MILES
Accidentally topped off brake fluid reservoir with half an ounce to one ounce of power steering fluid. (Only in spout of reservoir) Noticed immediately and turkey bastered it out (power steering fluid was floating on top). Drove it home (twenty miles) and had mechanic do a brake fluid flush the next day. What is my prognosis like? Any signs I should look out for prior to brake seizing?
Tuesday, February 13th, 2018 AT 6:44 AM

7 Replies

Tiny
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I think you will be okay.
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Tuesday, February 13th, 2018 AT 7:01 AM
Tiny
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Thanks for your quick reply. I saw some real horror stories online. How efficient is a brake fluid flush? Would it remove the remainder of the power steering fluid (however little may be) from the system?
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Tuesday, February 13th, 2018 AT 7:41 AM
Tiny
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If you never even pump the brake when you used the turkey baster, you probably removed most or all of it and the flush would have flushed out everything so no worries.
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Tuesday, February 13th, 2018 AT 7:52 AM
Tiny
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Just to test, I came home and sucked a bit (1/2 oz.) Of brake fluid from the top of the reservoir and mixed it into some water. The brake fluid mixed well with the water and there were no signs of oil/oil-based substance. I would imagine the oil would have floated to the top if present. Good sign I hope. I have a two hundred mile (each way) trip this weekend so I was a bit paranoid this whole thing.
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Tuesday, February 13th, 2018 AT 5:30 PM
Tiny
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I was reading some stories of how the power steering fluid can cause the seals in the brake system to swell and deteriorate. Although, that all depends on whether or not there is still any power steering fluid left over or the turkey baster and flushing removed it all.
It basically comes down to either two things. Do nothing but keep an eye on the brake fluid level and if you begin to see rapid fluid loss, then most likely a seal has blown and it is leaking. From what I read at that point you are probably going to have to replace everything that is associated with the braking system, which seams to me a bit paranoid but nonetheless that oil based power steering fluid is really bad for the brake system seals.
Or on the other hand you could just assume right now that it is contaminated and replace everything associated with the brakes which includes all the brake lines and hoses, too.
If it were me, I would do the first. Just keep an eye on the fluid level and keep my fingers crossed.

http://www.agcoauto.com/content/news/p2_articleid/251

Also, if you wanted to test the fluid, do not add any water, just suck out a little fluid put into a clear container, maybe one of those eye droppers, then let it sit still for an hour and see if you see a line of separation between the power steering fluid and the brake fluid and hopefully you will not see a line.
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Tuesday, February 13th, 2018 AT 5:43 PM
Tiny
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Just closing the loop on this topic. Hopefully it can be useful to others:

About 18 months ago I accidently put 1/2 ounce of power steering fluid in my brake fluid reservoir. I saw that the power steering fluid was floating toward the top and siphoned out as much as I could. I drove it home (probably shouldn't have) about 20 miles. The next day I took it to the mechanic who flushed the brake lines. Fortunately for me, I have not had any issues since. Though, I did read some things on the net that say the brake system will inevitably fail which scared the crap outta me. But 18 months later and everything is still good. Fingers crossed! I suggest getting out as much as possible and flushing the brake lines.
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Tuesday, July 23rd, 2019 AT 6:17 AM
Tiny
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Looks like you got it all out.
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Tuesday, July 23rd, 2019 AT 8:25 AM

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