Power steering fluid in brake fluid

R

ripcord

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Uncle Softy (me) needs richer relatives so I can tell them to take their cars to a real mechanic...

My brother texted that his broke college student kid topped off the brake fluid with power steering fluid. I know that if petroleum products get down in the system, we're supposed to replace everything with rubber. Hoses, calipers wheel cylinders, master cylinder, ABS unit, etc.

My question is which is heavier, the brake fluid or the petroleum based power steering fluid? It's only been driven once since it was added and supposedly only a "few ounces" were added. I'm hoping that the the PS fluid will be floating on top and I can over fill the reservoir and float most of the PS fluid out, then remove the master cylinder and spray it out with brake cleaner.

Thoughts? Wisdom? Experience? Thanks!
 
There is only a tiny orifice between the reservoir and MC, so you might get lucky. You do have to evaluate if any got into the passage down into the MC-- designs are all over the place for this. Treat the PS fluid like Ebola, you want any trace of it gone. Scorched earth.

Not sure what car this is, but some reservoirs snap off with no effort, others are held on with very little.

I would simply turkey baster everything you can get, then snap off the reservoir, and throw it out. A new one won't be much money.

Brake cleaner is kryptonite to brake fluid, and not great for the plastic in reservoirs either.
 
Starman2112 said:

AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - What Happens When Power Steering Fluid Is Put In The Brakes

AGCO provides overall lowest costs of vehicle ownership. We do this by providing extremely high quality automotive service, following the theories and practices of Dr. W. Edwards Deming., power steering fluid added to brakes
www.agcoauto.com www.agcoauto.com
Click to expand...
The info @Starman2112 provided directly answered your question and described the situation.

Scott
 
eljefino said:
There is only a tiny orifice between the reservoir and MC, so you might get lucky. You do have to evaluate if any got into the passage down into the MC-- designs are all over the place for this. Treat the PS fluid like Ebola, you want any trace of it gone. Scorched earth.

Not sure what car this is, but some reservoirs snap off with no effort, others are held on with very little.

I would simply turkey baster everything you can get, then snap off the reservoir, and throw it out. A new one won't be much money.

Brake cleaner is kryptonite to brake fluid, and not great for the plastic in reservoirs either.
Click to expand...

I'm thinking along these lines. Has it been driven? Brake fluid doesn't circulate through the system, the same fluid stays in the lines and just gets pushed back and forth.
 
ripcord said:
Dang! ABS modules for this application seem like unubtanium and are listed at $500ish.
Click to expand...
You have no real basis that the ABS system is damaged, do you?

Don’t be chicken little, yet. Get the fluid pulled from the reservoir, get a LOT of flushing done, then some more, and more from there.

Sure, I’d consider changing brake hoses. Probably a good excuse. While I have vehicles with >30 year old perfectly functional brake hoses, in time they can generate bulges or collapse. Petroleum if it’s going to do something, will probably get those. So swap the four lines. Not a huge deal.

See if you can find someone with a scan tool to cycle the ABS on the second flush. Don’t do it on the first in case there is still some petroleum in the reservoir. I don’t think all brake fluid always passes through all parts of the ABS pump. May be wrong…
 
JHZR2 said:
You have no real basis that the ABS system is damaged, do you?

Don’t be chicken little, yet. Get the fluid pulled from the reservoir, get a LOT of flushing done, then some more, and more from there.

Sure, I’d consider changing brake hoses. Probably a good excuse. While I have vehicles with >30 year old perfectly functional brake hoses, in time they can generate bulges or collapse. Petroleum if it’s going to do something, will probably get those. So swap the four lines. Not a huge deal.

See if you can find someone with a scan tool to cycle the ABS on the second flush. Don’t do it on the first in case there is still some petroleum in the reservoir. I don’t think all brake fluid always passes through all parts of the ABS pump. May be wrong…
Click to expand...
I've got Forscan and have bled ABS pumps before when I was unable to get rid of spongy brakes.

The question is how far has the contamination reached and how do I get it all out. Petroleum will supposedly soak into rubber components and make them swell, so any rubber that has been in contact with it will eventually cause problems.

I'm pretty sure that at a minimum, I'm going to replace the master cylinder and the hoses. I'll probably give it new rear wheel cylinders and rebuild the front calipers.

I've been reading about flushing with denatured alcohol, but I don't know enough about that yet to decide.
 
ripcord said:
I've got Forscan and have bled ABS pumps before when I was unable to get rid of spongy brakes.

The question is how far has the contamination reached and how do I get it all out. Petroleum will supposedly soak into rubber components and make them swell, so any rubber that has been in contact with it will eventually cause problems.

I'm pretty sure that at a minimum, I'm going to replace the master cylinder and the hoses. I'll probably give it new rear wheel cylinders and rebuild the front calipers.

I've been reading about flushing with denatured alcohol, but I don't know enough about that yet to decide.
Click to expand...
I mean, that’s great speculation. I don’t doubt that it can happen, and this is a brake system, so you want it working, sure. But without evidence of issues in, say, something like an abs pump, I wouldn’t be looking to throw too many parts too soon, unless there is a real issue observed.

Key is to triage by getting the old fluids out.
 
ripcord said:
I've got Forscan and have bled ABS pumps before when I was unable to get rid of spongy brakes.

The question is how far has the contamination reached and how do I get it all out. Petroleum will supposedly soak into rubber components and make them swell, so any rubber that has been in contact with it will eventually cause problems.

I'm pretty sure that at a minimum, I'm going to replace the master cylinder and the hoses. I'll probably give it new rear wheel cylinders and rebuild the front calipers.

I've been reading about flushing with denatured alcohol, but I don't know enough about that yet to decide.
Click to expand...
As others have posted draw all the fluid you can out and replace the reservoir, open the bleed screws one at a time and fill the reservoir with high % Isopropyl alcohol, bleed the brakes as you would if you were using brake fluid then let it go, let about a qt go through each wheel position. Triggering the ABS with a scan tool will help get the alcohol into the system. Flush it multiple times with brake fluid, time is not on your side with this, the longer epdm rubber is in contact with the PS fluid the more damage is done. Use this alcohol..


 
Well, I went with the flush option as Trav suggested. Suctioned out the reservoir first and ran gallon and a half of isopropyl alcohol through, cycling the ABS several times with Forscan on each wheel. Followed up by flushing with a gallon of DOT 3, again cycling the ABS for each corner.

Here's the first gallon of waste fluid. You can see the power steering fluid floating on top.

I kind of expect that I'll be getting a call about spongy brakes in a month or two. Hopefully not.

IMG_20240427_173958998_HDR.jpg
 
ripcord said:
Well, I went with the flush option as Trav suggested. Suctioned out the reservoir first and ran gallon and a half of isopropyl alcohol through, cycling the ABS several times with Forscan on each wheel. Followed up by flushing with a gallon of DOT 3, again cycling the ABS for each corner.

Here's the first gallon of waste fluid. You can see the power steering fluid floating on top.

I kind of expect that I'll be getting a call about spongy brakes in a month or two. Hopefully not.

View attachment 216498
Click to expand...
Looks like the fluids never changed before. I’d be more concerned about that.
 
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