Engine oil put in brake master cyl Page 1 / 3

frank1, Jul 19, 9:08pm
Don't even ask me why, but was put in there by mates ex--her car though.
How long before brake seals are stuffed?
1996 Toyota Corolla 1600

franc123, Jul 19, 9:16pm
They probably are already if it's been driven.

frank1, Jul 19, 9:25pm
Yep, my opinion too, will bleed system tomorrow and see what the result is.
Has not been driven far so I'm told--maybe 10kms.

milkath, Jul 19, 9:32pm
If it was only a top up and has not got into the brake lines it should able to be drained at the master cylinder. Brake fluid is designed to handle lots of heat and is much more corrosive than engine oil.
You could force the calipers open, forcing oil back to the reservoir and suck out the oil from the reservoir, say with a syringe, thereby getting rid of most of the engine oil.

kingfisher21, Jul 19, 9:57pm
Yup as above, dont go bleeding them without getting the oil out of the master cylinder first.

scuba, Jul 19, 10:46pm
I have removed a master cylinder turned upside down drained , flushed and cleaned the reservoir then refitted and bled the system but i could see the oil sitiing in the top of the reservoir and was confident it hadn't gone down into the master cylinder itself.

strobo, Jul 19, 11:45pm
I don't want to be a pessimist but If you have bled the system through the damage has already started !.Contaminated dot brake fluid with mineral oil @ 10kms is no good at all ,i know this from right back as a teenager accidentally topping up dads car brake reservoir with even linseed oil! didnt show the immediate effects but it did on a trip to oamaru and back . ! Just precautionary , If in doubt biff it all out , cleanse the entire fluid lines of every residual and reseal every thing calipers /master /clutch system too if in same line . . .You have some vehicles fitted with silicon seals as opposed to rubber seals ,they are more forgiving with use of hydraulic system type mineral oil HMSO but not so with engine mineral oil. About putting HSMO or engine mineral oil in DOT systems: Don't ever do this.
Within 12 hours the seals/hoses will have swollen enough that the system barely works. Probably within 18 hours, it is dangerous. Over then next few days it gets worse and function is essentially ruined.

intrade, Jul 20, 7:45am
remove it as quick as possible. i had to fully remove the bowl on a 86 hiace . symptom was brakes stated to lock up there was red fluid turned out to be atf. the guy smokes so much weed every day so in his mind thats what belongs in there as that was what was put there before . I took one look at it and said that is no brake fluid .
Worst case scenario you have to replace the master also .
Suck it all out
wash bowl with hot water then disconnect master and bleed flush master . Then you got to flush 2 liter new fluid thru all lines after you refitted clean bowl with fresh fluid.
Remove it soonest . One time as it was just contaminated by some other person who got a car i managed to get it out by cleaning just the bowl as engine oil sits on top of brake fluid .
brake fluid should be exchanged every 24 month anyhow its hygroscopic why it dont matters if you wash the bowl with hot water and compress air dry it, rest will be absorbed with the flush.

intrade, Jul 20, 7:51am
driving it has nothing to do with the problem that first guy with atf driven for 6 month only when it failed the brakes on wof did he come and show me what he put in there 6 month before as that was a warning on wof sheet if its got abs you would disconnect lines from master as you dont want conterminated stuff going in to a abs unit.

kazbanz, Jul 20, 8:38am
I wouldn't even have her drive the car to you.
Not because of the danger to her so much as there's a small chance the oil is just sitting there in the master on top of the brake fluid. So sucking the master dry and washing it out with fresh brake fluid MIGHT save her brakes. --Personally I doubt it and reckon she's up for a replacement master then a flush as a minimum.

jaydeess, Jul 20, 9:38am
On my dirt bike once, in the middle of nowhere, i was forced to put auto trans fluid in my brake reservoir. it worked for the day, but within a week the seals were destroyed, and expanded soo much they popped out the side of the caliper. so be very careful, fixing the problem.

sr2, Jul 20, 4:52pm
I dealt with at least half a dozen similar instances of fluid contamination when I was in the industry. Sadly the outcome was always having to replace every seal in the entire braking system, there is no quick fix for this one.

frank1, Jul 20, 5:06pm
Update, used an old battery hydrometer to suck fluid out of m/cyl then bled brakes, all ok---but then found out she had put the engine oil in the power steering reservoir not the brake master cyl, FFS, anyway put very little in as it was full anyway and no leaks any where, so left it as it was.

kazbanz, Jul 20, 5:12pm
believe it or not water is a better option.

intrade, Jul 20, 5:21pm
yes because brake fluid is hygroscopic its why you got to change it every 24 month cause its ending up with to much water in the fluid lowering the boiling point. by flushing it you remove water if its in there temporarily for emergency as fluid.

intrade, Jul 20, 5:22pm
yea well power steer is most times ATF automatic trans fluid usually detron 3
you can flush that by remove of return hose and block the hole on bowl fill till its purged .

franc123, Jul 20, 5:23pm
No harm done putting a new belly full of brake fluid in it then. I remember the old Citroens that had the central hydraulic system that drove everything, they used two types of fluid depending on the age of the car and people still got it wrong.

strobo, Jul 20, 6:23pm
ya what now?The power steering! ,gee it gets worse. That's sabotage or oopsy she simply didn't know .Power steering is different from brakes ,the fluid in the reservoir is constantly circulating through the system as soon as the motor is started running!.It wont be sitting at the top I can tell you that now !

kazbanz, Jul 20, 6:29pm
yea but nahh--I'd be cleaning that sucker out.

kazbanz, Jul 20, 6:30pm
Yep exactly.--and in a trailbike its straight master to line to caliper so easy to flush out

strobo, Jul 20, 6:39pm
You have one of those fancy brake fluid condition tools made by whoflungdung or onehunglow have you not ?;-)Im still using the trusty ol eyeometer but considering one like your's ! Any brand tips ?

strobo, Jul 20, 6:44pm
Just a side note and a heads up , the wof people are getting particular about fluids ,they do check ,just saying make sure the reservoirs are looking scrupulously clean and no trace elements of the wrong stuff.

strobo, Jul 20, 6:52pm
Thanks intrade . so they are a bit like go or nogo guage, 70% is a fair indication either way .mostly to measure moisture content , For those who are unaware moisture has air in it as intrade stated hygroscopic meaning abilty to absorb moisture this means if air is in the lines it will compress too easily. When this happens, your brakes will feel too soft or even spongy and not entirely from a localized airlock it;s also within the fluid itself .A bleed through with new fluid helps eliminate compressible air.

intrade, Jul 20, 6:55pm
no theyx have 6 leds ok fair bad and real bad. i had it test medium when it was real bad on led. The accuracy is 70% and it takes 5 secounds to measure straight in bowl of car with the cheap resistance one.
also i do remove the battery partial so to not drain it in the tool as them cheap tools all drain the AAA battery dead fine since years push battery in when i use it pull it off contact when done.

intrade, Jul 20, 7:05pm
used my 300$ flashlight in right hand and phone in left hand to take that immage just few minutes ago.
http://www.iforce.co.nz/View.aspx?i=1r2tyxgo.cys.jpg

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