Huge steering fluid leak

[RossBMWZseries]

So yesterday, reversing into my parking space at work, I felt the steering become stiff, saw a bit of smoke coming from under the car in the passenger's side. I shut the car and back on, steered but wheel was as stiff as a dead dog. Looked under the car and noticed a big puddle of fluid on the concrete. I also noticed the fluid leak ran down the S pipe, which explains the smoke. I haven't gotten around to check if it's the steering reservoir that needs replacement or if it's a hose leak. Nonetheless, I plan on replacing it all.

I have 2 questions;

I understand we have to use ATF (automatic transmission fluid) in the steering reservoir. Is that ACTUAL transmission fluid used for "power" steering that I can find at my local auto parts store? I'd hate to pour ATF in there and mess things up even more.

Also, I read some threads from our dearly missed Ron Stygar regarding this issue. He was mentioning that the part number changed in Z4M's manufactured after June 2007, mine is 03/06. Part number is 32 41 2 283 893. I can't seem to find any other number for this hose. Does anyone know if this will fit a 03/06 Z4M?

[Our03z4]

Originally Posted by RossBMWZseries

So yesterday, reversing into my parking space at work, I felt the steering become stiff, saw a bit of smoke coming from under the car in the passenger's side. I shut the car and back on, steered but wheel was as stiff as a dead dog. Looked under the car and noticed a big puddle of fluid on the concrete. I also noticed the fluid leak ran down the S pipe, which explains the smoke. I haven't gotten around to check if it's the steering reservoir that needs replacement or if it's a hose leak. Nonetheless, I plan on replacing it all.

I have 2 questions;

I understand we have to use ATF (automatic transmission fluid) in the steering reservoir. Is that ACTUAL transmission fluid used for "power" steering that I can find at my local auto parts store? I'd hate to pour ATF in there and mess things up even more.

Also, I read some threads from our dearly missed Ron Stygar regarding this issue. He was mentioning that the part number changed in Z4M's manufactured after June 2007, mine is 03/06. Part number is 32 41 2 283 893. I can't seem to find any other number for this hose. Does anyone know if this will fit a 03/06 Z4M?

I know this isn't much help but I do know that my other non BMW vehicles due take plain nothing fancy ATF for their power steering. Yep, actual trans fluid. Hope you get it figured out!

[XMetal]

Yes, our power steering uses ATF fluid. I have had great success using Mobil1 Synthetic ATF in both our X5 and MC

[StickMon]

I had a "near miss" on a massive fluid leak.
If you don't do up the flare fittings on the pump and rack just right, it can set the expansion line hard against the oil pan.
Mine had a hole rubbed 3/4 of the way through the line.
They did change the part number on that line at some point after doing a better job of attaching the rubber part to the aluminum part.

Here's the part I put in.
Put some Firesleeve over it for extra protection. Can't remember what I.D.

[yousefnjr]

Yes to ATF, not sure about the PN off the top of my head. Once you do figure out which one you need though, I’d recommend checking out ECS for a non-OEM line, IIRC half the price for the same thing. I got one a while back and fit was perfect, no leaks

[RossBMWZseries]

Thank you all for the responses. I went ahead and ordered the non OEM line as you suggested yousefnjr as several reviews indicated it met standards and fit of the OEM one. Part number is 32412283893, OEM is $248 and non OEM is $112. ATF leaked all over, even down the S pipe and X pipe, I think it even reached the mufflers. Anything I should use to wipe that off?

[elerner61]

My hose isn't leaking any fluid yet, but it is "sweating" fluid through to the outside of the hose (was under the car this weekend). Where do these typically fail?

[StickMon]

I pretty sure they upgraded it, hence the part number change, because they would weep where the aluminum part was crimped onto the rubber hose.
Mine almost failed due to a big notch worn where it was tight up against the oil pan.
Some previous wrencher didn't hold it in place while tightening the banjo bolt(s) so it was forced up against the oil pan.
Not sure we know yet where RossBMWZseries' failed.

[RossBMWZseries]

Originally Posted by elerner61

My hose isn't leaking any fluid yet, but it is "sweating" fluid through to the outside of the hose (was under the car this weekend). Where do these typically fail?

Originally Posted by StickMon

I pretty sure they upgraded it, hence the part number change, because they would weep where the aluminum part was crimped onto the rubber hose.
Mine almost failed due to a big notch worn where it was tight up against the oil pan.
Some previous wrencher didn't hold it in place while tightening the banjo bolt(s) so it was forced up against the oil pan.
Not sure we know yet where RossBMWZseries' failed.

From what I've read, it fails where StickMon's failed; where the aluminum and rubber meet. I wasn't able to see mine exactly where because it was covered in oil. I poured more ATF in the reservoir and turned the wheel a few times. Based on the stains on the concrete, the leak was coming from the hose itself, and I'm almost certain it was from the rubber/aluminum section. Once I remove the old part to install the new one, I'll compare them side by side and take pictures. I can tell you that the faulty OEM part was hanging from the U end point when I got to it. It looks like it somehow broke off.

[StickMon]

Mine didn't fail, but it was close:



This can also happen:



See thread: https://www.zpost.com/forums/showthread.php?t=750022

[RossBMWZseries]

That helps Stick Mon. I see you replaced yours years ago. Any issues since?

[StickMon]

Nope. Many years and many miles. All's been fine since.

[RossBMWZseries]

So I replaced the power steering hose today. I cleaned all the ATF and oil build up as much as I could, scrubbed the engine and transmission, S-Pipe, subframe, suspension, for hours. The common CPV oil leak must’ve deteriorated the small piece of rubber under the nut right on the “U” end of the power steering hose. The rubber was covered in oil and cut right in half, separating the hose from the bracket it was attached to. The hose bent down in the middle section, allowing the section leading to the banjo bolts to come up. The end on banjo 2 was touching the oil pan, where it began creating a small hole. When I installed the new one, I put pieces of thick cardboard between the hose and the oil pan, then I torqued the banjo bolts, removed the cardboard, and there was a satisfying gap between the oil pan and hose. Here are some pics;

[elerner61]

So I picked up a new hose to replace mine that is "sweating" but not dripping fluid. Do you still have the torque spec for the banjo bolt handy? Also, where will fluid drain from (just reservoir, just rack, reservoir and rack) once I undo the banjo bolts? I'd like to drain it all while I'm under there. Thx.

[RossBMWZseries]

Originally Posted by elerner61

So I picked up a new hose to replace mine that is "sweating" but not dripping fluid. Do you still have the torque spec for the banjo bolt handy? Also, where will fluid drain from (just reservoir, just rack, reservoir and rack) once I undo the banjo bolts? I'd like to drain it all while I'm under there. Thx.

Hey elerner. I did save the torque specs on my phone; 25lb/ft on banjo #2, which is 35NM, and 29.5 lb/ft on banjo #1 which is 40NM. I used google to convert the specs, it all depends on the torque tool you're using.

Once you undo the banjo bolts, the fluid will only leak from those ends. Unless there's more of a leak where the "sweating" is coming from. I used rags to absorb it all but keep in mind mine had leaked it all on the street so there wasn't much to absorb. If you're not vacuuming out the ATF, my suggestion is you get 2 containers down there to be ready to catch it from each banjo.

[elerner61]

Originally Posted by RossBMWZseries

Hey elerner. I did save the torque specs on my phone; 25lb/ft on banjo #2, which is 35NM, and 29.5 lb/ft on banjo #1 which is 40NM. I used google to convert the specs, it all depends on the torque tool you're using.

Once you undo the banjo bolts, the fluid will only leak from those ends. Unless there's more of a leak where the "sweating" is coming from. I used rags to absorb it all but keep in mind mine had leaked it all on the street so there wasn't much to absorb. If you're not vacuuming out the ATF, my suggestion is you get 2 containers down there to be ready to catch it from each banjo.

Hi Ross. Thanks for the info. I happened to also find it in the TIS online (think I found it) and what I'm seeing is a little different than your values. I don't need to be right, just want the right values. I see 33NM and 35NM in the links below. Thoughts on this?

https://workshop-manuals.com/bmw/z_s...nd_oil_supply/

https://workshop-manuals.com/bmw/z_s...ply/page_3036/

[RossBMWZseries]

Originally Posted by elerner61

Hi Ross. Thanks for the info. I happened to also find it in the TIS online (think I found it) and what I'm seeing is a little different than your values. I don't need to be right, just want the right values. I see 33NM and 35NM in the links below. Thoughts on this?

https://workshop-manuals.com/bmw/z_s...nd_oil_supply/

https://workshop-manuals.com/bmw/z_s...ply/page_3036/

I got the specs from Post #1 on the thread below. I torqued mine down to the values listed there back when I did this on 11/11/2018 and just when I inspected it on the lift on 12/08/2018, there was still no leak AT ALL coming from the banjo bolts. My guess is they're holding on tight enough without breaking. However, I would say go with the TIS info. I know I would've had I had that info.

http://www.m3forum.net/m3forum/showt...power+steering