85 735i PS/Brakes

[MikeinLV]

Hello all,

My son just purchased an 85 735i, not having a manual (yet) his PS pump is making an awful noise when turning the wheel and pressing on the brake pedal. I have been reading thru this forum and I'm confused. I was under the impression that the PS and brakes used the same fluid, then I read use ATF for PS and DOT4 for brakes. Could someone set me straight?

Thanks in advance!
Mike

[Byron]

It is critical that these two fluids are not confused. ATF can be used for PS. Brake fluid must be used for the brake system. no substitution

[ROYinGA]

[MikeinLV]

Thanks for the replies!

I presume there are 2 different tanks for these fluids?

The reason I'm asking is my son told me that the PS pump runs both the brakes and the PS, I thought he was crazy but he said that's what the previous owner told him.

Thanks again!

Mike

[ROYinGA]

system that boosts the steering. There is a metal reservoir can for the ATF. The brake master cylinder is like other cars with a plastic reservoir on top of it for the normal DOT 3 or 4 brake fluid. The booster cylinder is between the master cylinder and the firewall. Do a search for "brake bomb" and it will tell you how to properly check the fluid level for the ATF reservoir.

[MikeinLV]

Hi Roy,

Thank you very much for this information. My son will be happy, cause I won't let him drive my '66 GTO, this way he can have his car.

Mike

[Ray7er6ers5er3er]

silver canister with the nurled nut on top, towards the front drivers side in the engine compartment. If you put brake fluid in there it's got to come out, be flushed and refilled. To test fluid level, pump the brakes (engine off) about 15-20 times, until the pedal gets real hard...THEN fill to 1/2" below rim.

The brake fluid resivoir is near the fire wall, similar to any cars, simply fill to level indicated with PS fluid.

The PS canister should have been better marked in my opinion, with a warning label.

[7er]

I have put in there "*****ton"- is that good for the system?