[ENINTY]

Originally Posted by Rotorocious

I'm a bit confused but think I know what you mean.
Could you elaborate a bit?

He is saying, instead of draining the system by removing one of the hydraulic lines, just suck the power steering fluid out of the reservoir and refill with fresh fluid. The do it once or twice more and the system will have all fresh fluid in it.

[AlanAZ]

do it once or twice more and the system will have all fresh fluid in it

Statistically it takes many flushes to get all the old fluid out this way.

Replacing the fluid in the reservoir only, and not the pump and rack, you're getting maybe 50% of the old fluid, so with the first flush, you get 50%, the second another 25%, third another 12.5%, etc. And with each subsequent flush you're taking out more and more new fluid, an expensive way to do it.

The ideal method is to combine the two. Replace the fluid in the res., and then open the hose and pump the fluid out, the second half of this would be new fluid from the reservoir. If I'd gone full term mileage on my fluid I'd do it this way, it would take buying another liter.

[Glim]

After replacing 1 quart using the bleeder bottle method the fluid is not 100% new looking but it looks much better than it did originally, yes I would say an 85% improvement. It was so easy to do, as such I plan to do this annually.

[skybox]

How do I fine the reservoir tank? Can some one post a pix or tell me the location of the tank. My Steering light keep coming on here and there. I'm not sure what to look for.
Thanks!

[cstmx_ryder]

How do you know when it's time to flush out the PS fluid? And what noises are you referring to when turning the steering wheel?

Does it make a 'gunk gunk' noise? Because I'm experiencing that now and couldn't figure out what's wrong....I only hear it on the driver side though.

TIA

[Multibimmer]

Very nice write-up, thanks. I plan to do the power steering flush on my wife's 07 328i (71,500 miles) tomorrow. I checked the reservoir today, and was shocked to find the level quite low. I'm not getting any warning lights, so hopefully I've caught it in time.

Just one question - should I replace the crush washers on the banjo bolt used to drain the fluid? I know these would be a dealer item, but the dealer is a very long drive for me. I'll definitely change them if it's recommended, but just want to hear the consensus first. Thanks.

Edit: Never mind - I read through this thread again, and saw that the Bentley manual recommends replacing the crush washers, so I'll go ahead and get some.

[Multibimmer]

OK, I did the flush and fill procedure, and everything went fine - a very easy job overall. However, once I've refilled the reservoir, turned the wheel to full lock positions about 8 times, and turned on the engine, there's a loud, god-awful noise coming from the steering, I assume the pump. When turned the engine off and checked the reservoir, there was still fluid in it, although it had gone down some, but the fluid in the reservoir is very frothy (i.e. it has lots of visible small bubbles). So, hoping the noise was just caused by air in the system, I topped up the reservoir, and turned the engine on again, but got the same noise.

I didn't see anyone else comment on this. Is this normal? I didn't have any issues with the job whatsoever - there are no leaks, the new crush washers went on just fine, etc. Any comments or ideas? I just topped it off again, and will try turning the engine on once more. Thanks.

[Multibimmer]

After topping it off again, and turning on the engine, it made the noise for just a few seconds, then quieted down. Whew! Must have just been some air trapped in the system. Took it for a spin around the block, and no noise, and the steering feels fine. The fluid did get very low, though - I measured 650 ml, and I drained the old fluid very thoroughly, turning it to one side, waiting until it stopped draining, turning it to the other side, etc., at least eight times. I didn't measure exactly how much of the new fluid I poured in, but there is very little left of the 1 liter can. I hope I didn't damage the pump by letting the fluid get so low. I like to pride myself on maintaining my cars very well, but I blew it on this one. Will pay closer attention from now on. I wonder how the fluid got so low... there are no signs of anything dripping on the garage floor, and the hoses look very dry. Maybe it was slightly under-filled at the factory, and it has just very slowly seeped out somehow. Anyone else experience this?

[AlanAZ]

However, once I've refilled the reservoir, turned the wheel to full lock positions about 8 times, and turned on the engine, there's a loud, god-awful noise coming from the steering, I assume the pump. When turned the engine off and checked the reservoir, there was still fluid in it, although it had gone down some, but the fluid in the reservoir is very frothy (i.e. it has lots of visible small bubbles).

Noise is air in the pump. Turning the wheel lock to lock on filling doesn't help. Only the pump can get fluid into the rack.

You want to bleed the air from the pump and lines by turning on the engine for just a few seconds (off before you hear a noise), then refill the reservoir, repeat.

[Multibimmer]

Thanks; you did say that in your DIY. I was swayed by another poster who quoted doing is different per the Bentley manual. Next time, I'll do it the way you describe. Other than the small scare from the cavitation noise, the job was very easy and painless.

[jacobsed]

So do we need 1L or 2L for this job?

[uno]

Can someone please confirm that this is the correct PS fluid. Thanks a lot.

http://www.amazon.com/Pentosin-CHF-1.../dp/B0006Q16YM

[jacobsed]

It will say on the power steering reservoir cap. It is either that fluid or ATF.

[duaux]

Can anyone confirm the part# of the crush washers please?
I would like to to go to the dealer and get the correct one's (2x).

I believe they are either #6 or #11 from the following diagram:
RealOEM
http://www.realoem.com/bmw/showparts...74&hg=32&fg=20

I have an E90 2006 325i.

#6
A14X20-CUSN 32411093596
OR
A14X18-CUSN 07119906464

#11
A16X22 SFCU F22 32416778543
OR
A16X20-CUSN 07119906463

Thanks.


UPDATE: A14X18-CUSN 07119906464 <-- Confirmed by forum members, later in this thread.

[AlanAZ]

Crush washer (corrected): If you are draining per instructions on first post, you want #6, part number 07119906464 x2.

Fluid: provided your reservoir cap reads CHF-11S, this fluid on Amazon is the right one, but expensive with shipping. I bought it for $25 at the dealer.

1 liter. Read the first post.

[PINeely]

I got 2L of Pentosin CHF-11S at Napa for about 16 bucks each, planning to change mine when it stops raining.

[duaux]

AlanAZ: Thank you for confirming.

PINeely: Thats good to know that NAPA has it cheaper... will check.

[ENINTY]

Originally Posted by jacobsed

So do we need 1L or 2L for this job?

I drained my system completely and refilled it with less than 1 L of new Pentosin. You only need 1 L.

[duaux]

ENINTY: Thanks for sharing that, should save some ppl from buying an extra can. Although that wouldn't be a bad idea.

Anyone: My power steering cap says ATF.
What is the recommended ATF fluid for E90's that require it for power steering?
I have read others using Castrol Multi Vehicle ATF and Mobil 1 Full Synthetic ATF.

For those with the cap that say CHF-11S, use Pentosin. What about ATF?

Please advise.

[AlanAZ]

What is the recommended ATF fluid for E90's that require it for power steering?

Mike Miller recommends Redline D4 ATF, and not their synthetic power steering fluid - squeals when cold start in cold weather. I would double check with Redline, now that they have D6 ATF, which would be best. They generally email back in a day.

[duaux]

AlanAZ: Good point.

I just recently bought some Redline D6 ATF as I was planning on changing my Manual Transmission fluid. Using the application guide on Redline's page, it noted that I required D6 ATF for my manual tranny.

However, since you gave me the pointer to email Redline, I thought I would try entering in Automatic transmission instead of Manual first... the result...

Redline Application Guide's Recommendation
"D4 ATF
For use in automatic transmission
This product also used as Power Steering Fluid in this vehicle"

Seems like I got my answer. For those searching and interested, here is a recap of ***possible power steering fluid for our E90's.

If your PS cap says:
1) CHF-11S, use Pentosin only
2) ATF, seems like we have some choices...
-Redline D4 ATF
-Mobil 1 Full Synthetic ATF
-Castrol Multi Vehicle ATF

[mthomas]

I modified the original approach as I could not envision how to do it without making a complete mess of the vehicle and garage floor. I think this is actually the e46 method referenced by the OP in his posting.

Less messy technique:

Lift front of vehicle. Please do this safely.

Remove plastic underbody, air box, and air intake duct from in front of engine to aid access.

Release the tension on the serpentine belt, and move it out of the way to improve access and prevent getting any oil on to it. This is a great time to do maintenance in this area as well.

Completely drain the reservoir with your suction device of choice. Get down behind the filter to minimize mess in the next step. I got about 250 ml out, it was a little bit low to start.

Remove the banjo bolt at the bottom of the PS pump. I removed by reaching in from above. This allowed me to place some aluminum foil, prior to opening the bolt, below and channel the fluid forward and into a container with a funnel on top, with minimal mess. It is also an easy bolt to access, and retighten.

Turning the steering wheel repeatedly from stop to stop for about five or ten minutes will pump fluid up to the reservoir, which will then drain down to the pump and out the bottom. I also used a small syringe to again fully empty the reservoir. I was able to get another 450 ml of fluid out.

Replace the banjo bolt and line, use new crush washers.

Degrease any pulleys that might have been contaminated, then replaced serpentine belt.

I refilled with 700 ml of fluid. This takes a little while, turn the steering wheel, start and stop the engine, etc. Ignored the horrible noises, got the air out and ran the engine for a while, then emptied the reservoir again and refilled with the remaining 300 ml in the can.

Assuming a 1 liter capacity (complete guess), this means the first flush left 30% old fluid, and the second, reservoir only, flush got it down to about 22% old fluid. Looks much better, but I wish there was a way to get all the fluid out. Using the easier drain reservoir and refill method, five cycles should get you to the same place, but would require 1.25 liters of fluid.Hope this helps someone. Sorry no pics, there are plenty of them above. The PS pump is right above the rack and to the front. Just trace the lines.