Hydraulic fluid overflowing

[JAK]

Hi there everyone,

I'm new to the forum and am in need of help.
Recently, my brother had mixed the hydraulic/steering fluid with something bad from canadian tire.

A few days later the old stuff + mixed with the new started overflowing from the reservoir. I thought maybe it was a reaction of the two fluid which caused it and the next day when i saw the reservoir tank i noticed it was kind of foamy and bubbly. By the following morning, when I had taken a second look the tank was completely empty.

So I went to BMW and bought the good stuff (Pentosin ch7.1) and put that in. A few days later, that, too, had overflown coming from the top of the reservoir. And there must have been some sort of pressure that it leaked from the top with the bolt/screw thing on.

What do you think my problem could be? Could it be the pump/rack? Or has anyone else come across this to suggest anything?


Thank you very much

JAK

[joshua43214]

What was put in it? does the label specify ch7.1? mine uses chf11s. What kind of car is it? I assume a BMW but they made alot of different cars. Really ned a little bit of help from you if you want help from us

[Bill R.]

hydroboost and you have a bad valve in it then it will overfill the reservoir if the car sits overnight for example.

Hi there everyone,

I'm new to the forum and am in need of help.
Recently, my brother had mixed the hydraulic/steering fluid with something bad from canadian tire.

A few days later the old stuff + mixed with the new started overflowing from the reservoir. I thought maybe it was a reaction of the two fluid which caused it and the next day when i saw the reservoir tank i noticed it was kind of foamy and bubbly. By the following morning, when I had taken a second look the tank was completely empty.

So I went to BMW and bought the good stuff (Pentosin ch7.1) and put that in. A few days later, that, too, had overflown coming from the top of the reservoir. And there must have been some sort of pressure that it leaked from the top with the bolt/screw thing on.

What do you think my problem could be? Could it be the pump/rack? Or has anyone else come across this to suggest anything?


Thank you very much

JAK

[rob101]

hydroboost and you have a bad valve in it then it will overfill the reservoir if the car sits overnight for example.

do you mean the brake booster that runs off the power steering, I have had this happen to me, the brake booster does weird things to the level of the hydraulic fluid

[Bill R.]

brake booster then the only accurate way to check the level is to have the car sitting cold and with the engine and key off, pump the brake pedal at least 20 times. Then check the fluid level in the hydraulic reservoir. When you pump the brake you bleed out all the pressure thats stored in the pressure accumulator and the fluid level will rise. So you fill it to the mark when all the pressure is bled out and then you start the car. The fluid level will go down quite a bit but you don't add any more to it, unless you always pump the pedal 20 times before checking.

do you mean the brake booster that runs off the power steering, I have had this happen to me, the brake booster does weird things to the level of the hydraulic fluid

[winfred]

yep, and sometimes it will lock the brakes while sitting in traffic if it's overfilled too if the reservoir cap seals good enough, the brakes won't release till you get off the pedal and the pump sucks the fluid down, i don't like to fill it more then about a inch from the top at it's highest point, usually to the bottom of the screen on the cars with the big metal reservoir

brake booster then the only accurate way to check the level is to have the car sitting cold and with the engine and key off, pump the brake pedal at least 20 times. Then check the fluid level in the hydraulic reservoir. When you pump the brake you bleed out all the pressure thats stored in the pressure accumulator and the fluid level will rise. So you fill it to the mark when all the pressure is bled out and then you start the car. The fluid level will go down quite a bit but you don't add any more to it, unless you always pump the pedal 20 times before checking.

[rob101]

yep, and sometimes it will lock the brakes while sitting in traffic if it's overfilled too if the reservoir cap seals good enough, the brakes won't release till you get off the pedal and the pump sucks the fluid down, i don't like to fill it more then about a inch from the top at it's highest point, usually to the bottom of the screen on the cars with the big metal reservoir

oooh sounds like fun not!
nah i had my e28 parked up on a slope in the car port one day and a far amount leaked out after changing the accumulator, anyway its all good now.

[genphreak]

oooh sounds like fun not!
nah i had my e28 parked up on a slope in the car port one day and a far amount leaked out after changing the accumulator, anyway its all good now.

A lot of the time the cap seal goes and no one thinks to replaces it. They it lets air in and your fluid goes off, you get rust in the system and everything (master cyl, calipers, etc) just screws up.

It's always worth making sure your cap seal is good for the sake of $2. nick

[rob101]

A lot of the time the cap seal goes and no one thinks to replaces it. They it lets air in and your fluid goes off, you get rust in the system and everything (master cyl, calipers, etc) just screws up.

It's always worth making sure your cap seal is good for the sake of $2. nick

well i did recently replace the Brake master cap but i think you are getting mixed up with the brake hydraulic system.
we're talking about the hydraulic oil in the powersteering circuit as some earlier bmws don't run vacuum brake boosters, they run the brake boost off the powersteering hydraulic circuit. it seeped out because the reserviour overflowed because when i opened it was full the brim (and its only meant to be up the metal mesh part).

[mamilapon]

Hi there everyone,

I'm new to the forum and am in need of help.
Recently, my brother had mixed the hydraulic/steering fluid with something bad from canadian tire.

A few days later the old stuff + mixed with the new started overflowing from the reservoir. I thought maybe it was a reaction of the two fluid which caused it and the next day when i saw the reservoir tank i noticed it was kind of foamy and bubbly. By the following morning, when I had taken a second look the tank was completely empty.

So I went to BMW and bought the good stuff (Pentosin ch7.1) and put that in. A few days later, that, too, had overflown coming from the top of the reservoir. And there must have been some sort of pressure that it leaked from the top with the bolt/screw thing on.

What do you think my problem could be? Could it be the pump/rack? Or has anyone else come across this to suggest anything?


Thank you very much

JAK

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