Jump to content
whiskychaser

Which power steering fluid?

Recommended Posts

Trying to establish if it is ATF or CHF 7.1 which of course you cannot mix. Local BMW say they used ATF up to 2001 but I've read they used ATF up to 92/93 then changed. There is no label on the reservoir and the cap just says 'ZF'. ATF is red and AFIK CHF 7.1 is green. The stuff in there is yellow. Anyone have a definitive answer or point of reference please?

Share this post


Link to post
Share on other sites

I pretty sure I topped mine up with CHF recently. Mine also says ZF on the cap, but I think the bottle said something about I could mix with other fluids. Not 100% as id need the bottle to look. What does the manual say? Im sure I checked that as well otherwise I wouldn't of put it in!

I believe ZF is the name of manufacture of the power steering system. Does it say anything in small print on the cap also? I can't remember if mine said SAE something or other.

Share this post


Link to post
Share on other sites

Thanks for the response :) The handbook says refer to BMW. Bentleys says ATF or CHF 7.1. The cap just says ZF.

I found sites that said Pentosin CHF 11S is good for 9/91 onwards (Pentosin's own site says 1990 on). In fact there is an item in TIS that says BMW went from 7.1 to 11S in 9/91 but that was the E32. I know you cant mix 7.1 and 11S but you probably cant get hold of 7.1 anymore. I've read if you put ATF into a CHF system it can wreck it but nothing the other way round. The old stuff isnt red so I think I will blast it all out and fill with 11S. Somebody shout if you know otherwise...

Share this post


Link to post
Share on other sites

When I get in il look at my bottle of fluid! The stuff I used is green. ATF is red and im not totally sure it would be used on a hydraulic system. Il let you know what I put in mine in a few hours.

Share this post


Link to post
Share on other sites
Yeah oils and hydraulic fluid is a mine field! Right I used CHF 11S and yes you can't mix it with ATF according to the bottle!

Sounds good to me. I plan to fix the weep then disconnect the return and let the pump do the work as per ZF's instructions. Hope nobody has been topping up with atf...

Share this post


Link to post
Share on other sites

DEXRON II is obsolete and may be quite hard to get hold of - DEXRON III is the replacement.

Metalhead: DEXRON III (which is a red coloured ATF) seems to be a common fluid to use in hydraulic systems for military vehicles amongst other mobile platforms requiring hydraulic power transmission.

Share this post


Link to post
Share on other sites

Oh right, mines got green stuff in it! Hence using CHF11s. Confusing or what! And cheers for the info on ATF. I wasn't aware it was used on hydraulic systems. They can't keep it simple these car manufactures can they!

Share this post


Link to post
Share on other sites

Reserection.....

Whiskychaser, Hayes states dexron II type ATF. What in my car already is red (1990 535i).

Did you get a conclusive answer on this question? ie the spec of fluid that should be used?

Edited by Hogie

Share this post


Link to post
Share on other sites

Reserection.....

Whiskychaser, Hayes states dexron II type ATF. What in my car already is red (1990 535i).

Did you get a conclusive answer on this question? ie the spec of fluid that should be used?

No, I didn't get a conclusive answer. It isn't quite as simple as 'it only takes CHF if the reservoir is metal' either. As ATF could possibly wreck the system but CHF wouldn't, I used the latter.

 

Dexron is red so unless you have leaks or problems, I'd stick with that.  

Share this post


Link to post
Share on other sites

Thanks, I'll stick to the dexron then.

My steering feels nice and light when I first start driving the car but when it's warmed up it gets a littler heavier. It's still assisted but just a little heavier......

Share this post


Link to post
Share on other sites

Hogie

Your ride definitely takes dexron ATF. It should obviously be a ruby red colour,but after all these years it likely a dull dark burnt brown/red, well worth changing IMO.

Its a messy job to get it all out though. You'll need to drain the reservoir and the box by disconnecting the required unions and turning the wheel lock to lock to empty as much as you can out of the box. Try not to let it run dry when refilling or you risk pump damage.

If your car has servotronic steering this could be why the feedback is changing once warm which could indicate a fault. You can easily tell if it is fitted with servotronic if there is a loom with plug coming out of the box. A lot of e32 carried the system but not quite as many e34 had it fitted.

I have heard that fresh fluid does improve a lot of e34 steering woes.

Share this post


Link to post
Share on other sites

Five-oh makes a good point about running the pump. There's a DIY around about replacing the fluid by putting the pump return into a bucket and running the engine. The idea is you keep topping up the reservoir with new fluid until it starts to come out clean in the bucket. I tried it and it didn't work. You cannot fill the reservoir fast enough to keep up and you can end up with cavitation in the pump. That doesn't do it a lot of good.  

Share this post


Link to post
Share on other sites

If you don't get all the old stuff out I don't think it is the end of the world. At least you've refreshed it.

Edited by Tuvoc

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×