power steering flush - reservoir hoses

[darmstrong]

I prefer to do a true fluid flush when possible - which means open a line in the system to expel all old fluid, instead of simply trying to dilute old fluid with new.

I'd like to 100% confirm which hose is the reservoir return hose, though, before I brake off the non-reusable hose clamp. Haven't found a definitive drawing illustration online, but I do see this from RealOEM:

RealOEM.png

No.	Description	Supp.	Qty	From	Up To	Part Number	Price		Notes
01	Intake manifold		1			32411095526	$32.68
02	Hose clamp	D=20,9-24,1	2			32111131345	$2.12
03	PRESSURE HOSE ASSY		1	10/1998		32411095952	$218.88		+core
04	Gasket ring	D=7,65MM	1			64508390601	$1.93
05	Hollow bolt	M14X1,5X26	1		02/2012	32416783886	$2.11
05	Hollow bolt	M14X1,5X26	1			32416852469
06	Gasket ring	A14X20-CUSN	2			32411093596	$0.31
07	Return pipe		1	10/1998		32411094811	$61.05
08	Hose clamp	D=16,6-20MM	3			16121180242	$1.08
09	COOLING LINE		1			32411093638	$86.44

The point here is, the hose clamp for 01 - Intake manifold - is a 20-24 mm diameter clamp, and the hose clamp for 07 - Return pipe - is a a 16-20 mm diameter clamp. So I'm assuming that this confirms that the return hose is the smaller diameter hose.

For additional reference, here's a clear picture of the part:
GrotonPart4.jpg

. . . which shows that a larger diameter hose goes on the outside edge.

And another with what I believe is showing the return hose removed:

ReturnHoseOff.jpg

If all this is accurate, it would mean that the smaller return hose connection enters under the screen inside the reservoir, and the filtered fluid exits near the outside edge of the reservoir through the larger hose; makes sense.

Just hoping someone can confirm.


Thanks,

David

[Vintage42]

With 47,500 miles, I was too lazy to drain the reservoir. I sucked it down, about 10 oz. and the fluid was still clear pink.

There was seepage from the cap, which would attract dust, and once a year I would wipe it clean. The hoses and bottom of the reservoir were clean, so I figured the O-ring gasket in the cap was not sealing perfectly. I ordered a new O-ring gasket, 32 41 1 128 333 for $4.00.

The old gasket could not be felt then tightening the cap. It could also barely be seen, shrunken in its groove, and was too rigid to get hold of to pry off, so I cut it. The new gasket had life, was easily stretched over the threads, bulged in its groove, and could be felt when tightening the cap.

This should end the seepage from the cap. And I will do a few more sequential fluid refills over the months, a serial dilution of old fluid with new.

[rf900rkw]

If you're not going to change the filter, why bother?

[gmushial]

If you're not going to change the filter, why bother?

Where is the filter?

[Dakar Ole]

A new o-ring did nothing for me. It must come out the breather hole on top. The fluid in my car is always left near the min. line and that seems to help with the dispersion.

[daven]

If you want to read a long discussion on PS caps with one of the Z3 guru's ........

http://www.bimmerfest.com/forums/sho...r+steering+cap

[rf900rkw]

The filter is part of the reservoir. Replace the whole thing, and the two hoses the st are surely leaking.

[Vintage42]

The filter is part of the reservoir. Replace the whole thing, and the two hoses the st are surely leaking.

I was curious about that. Looked and felt the hoses, blotted the bottom of the reservoir. Those areas were bone dry. Just an oily dusty coating on the reservoir top after a year. Nothing was leaking. Sucking and replacing was so easy. And the new O-ring was so different from the old one.
As for the breather hole, how does the fluid become misted into air and come out of that hole?

- - - Updated - - -

If you want to read a long discussion on PS caps with one of the Z3 guru's ........
http://www.bimmerfest.com/forums/sho...r+steering+cap

Wow, Ron S was on this.