Power steering fluid in brake system

[TommyJ1980]

New master is bench-blend and in place, turning my attention to the seized caliper now.

 

[454cid]

Isn't the ABS out of the loop unless activated? That's what I've always heard for our trucks. I'd think that might be the one thing still ok.

 

[TommyJ1980]

What a day guys. Got the master cylinder in, both front brake calipers and attached hose. Just about went insane trying to get the rear brake line to thread back into the hole in the drum. I’ve never seen anything like those fine threads that just wouldn’t go back in, finally caught the thread after about 20 min, beyond aggravating. Anyways, headed out to bleed the brakes, hopefully driveable by tomorrow when I’m back to work. It was nice to get all that old fluid replaced with nice clean stuff.

 

[TommyJ1980]

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[GrimsterGMC]

What a day guys. Got the master cylinder in, both front brake calipers and attached hose. Just about went insane trying to get the rear brake line to thread back into the hole in the drum. I’ve never seen anything like those fine threads that just wouldn’t go back in, finally caught the thread after about 20 min, beyond aggravating. Anyways, headed out to bleed the brakes, hopefully driveable by tomorrow when I’m back to work. It was nice to get all that old fluid replaced with nice clean stuff.

I find it is easier to loosen off the bolts on the wheel cylinders so you can wriggle them around to catch the threads, rather than tugging on the rigid lines.

 

[someotherguy]

Different chemistry. Brake fluid isn't petroleum based. Doesn't automatically mean the rubber is shot though.

Very different chemistry. Typical brake fluids (dot 3/4) are ethylene glycol based, whereas power steering fluid is usually mineral oil based. I'm no chemist but seals and hoses used with various fluids are chosen based on the fluids intended to be used in that system.

Just because a hose or seal is "rubber" doesn't mean much. You wouldn't use regular rubber vacuum line in an emissions application, like the vent line back to your fuel tank or evap canister, because the fuel vapor (and occasional liquid fuel if overfilled) would immediately eat the lower-grade vacuum line. A heater hose subjected to oil will rapidly fail because it's not a chemical composition designed to be oil resistant. (I just about burned my 3500HD down by using a section of heater hose to temporarily short out an oil cooler while waiting for the correct radiator to ship.)

Those suggesting to replace everything in the brake system that has a rubber seal or hose in it are 100% correct. Failure is likely imminent in each one of those areas and these are your brakes; it is a life and death issue.

Richard

 

[Erik the Awful]

Flush those metal lines out!

When I was a Nissan tech we had a customer who'd put power steering fluid in the brake reservoir of his 300ZX. When he got the bill for an entire brake system replacement, he decided to ditch the ABS and save a couple grand.

 

[TommyJ1980]

To top it off, O’reillys sold me a leaking master cylinder. Figured that out after bleeding all 4 corners 3 times and still not having any pedal pressure…

 

[someotherguy]

To top it off, O’reillys sold me a leaking master cylinder. Figured that out after bleeding all 4 corners 3 times and still not having any pedal pressure…

It's not just O'Reilly's, it's pretty much anywhere you might source such a part. It's one of the items notorious for crap quality right out of the box these days.

Richard

 

[GoToGuy]

You own a vehicle. If you don't know, don't guess. If you have an owners manual for your truck do a search there are free downloads of your year model.
Rule of thumb. Don't guess, look in the owners manual. If your mechanically inclined you can download OE service manuals in the forum.
Don not just grab any bottle of fluid without reading the label. Is it the correct fluid for whatever your servicing? Containers come in every color of the rainbow, RTFL, Gumby. If your drain or store some fluid that is NOT what the label is. Rewrite what you placed in it. Don't use drink containers, you set yourself up for a trip to the ER. There's a story about Gatorade bottle on a toolbox, use your imagination.
If you came into my shop with your brake contamination problem. There are actual mechanical, safety, and liability factors. Incompatible fluids. Incompatible materials. Reduced braking, no brakes, locked brakes.
The brake hose lining is the same rubber blend as the rest of black rubber hydraulic brake materials. And that lining can swell or break away causing issues. The exception would be any hose that's Teflon, it's resistant/ compatible with any fluids automotive. Is really worth risking you, your family, other people, for what a hundred in brake hose? A half a cart of groceries is almost a 100 now, brake hose will last a decade or more. Sometimes your the bat, sometimes your the ball.
Good luck.