Welcome to the forum. Look at RealOEM.com. Choose e46 with a 2.5 And go from there. Of course you can also put in the last 7 digits of your VIN and explore parts for your car.

 

Other suggestions- if you're looking for pressure hose options, look at the xi variant,
and also E39's, X3's, X5's and E60's, all of which got the M54. You may be able to
find parts that work in the Z4 from one of those.
And don't limit to the 2.5- 2.3, 2.8 and 3.0 blocks are all the same as far
as mounting bosses.
DO be careful as to pumps- there are variations, and the hoses
are (sometimes) specific to those.

BMW pleasantly reused a lot of development, so parts swapping
has lots of places to go looking.

Also, any competent hose place that can work with metric
fittings can make you a hose from 2 ends and a length dimension.

hth
t

 

My buddy did the conversion. There was no non-M steering rack cooler, so the front crash bar was never designed for it, and therefore you can't dig into the parts bin. He bought an aftermarket cooler with AN fittings and had to wrap around the frame rail like behind the headlight.

You'll need the E85 Z4M steering column to fit the E46 rack properly. You'll need to code out the electric steering to eliminate the cluster light. Best of luck.

 

Hani - many thanks for the suggestion, will certainly try that, I have heard of REalOEM.com but is it a UK Company ? Unfortunately using my VIN would not yield much as the car would not be recognised as having hydraulic steering.

 

Many thanks for all your replies, I have to humbly admit when registering for the forum I thought it was UK based so my requests for hose details would have been based upon RHD steering. However all your views have been extremely useful and any continued suggestions for the implementation of a hydraulic conversation from the failing Z4 electric are highly valued. One of my questions (for which I have yet to get a specific view point) is whether the implementation of a cooler pipe is strictly necessary in conjunction with either the LF-20 or LF-30 pump, I have heard it all depends upon how you use your car, for me my Z4 is a casual use car so is it really worth the effort to install ??

 

I wouldnt be concerned based on no evidence that i have other than the observation that heat is only generated if the steerings used alot say city driving.Just one more place to leak.

 

I am in the process of a power steering conversion from electric to hydraulic and have eventually acquired nearly all the required components to start the work.on my Z4 (E46 based chassis). I planned to use the LF-30 pump (120 bar) but have managed to acquire a pump from a 3.0 ltr X Series BMW in excellent condition. The pump physically is identical externally to the LF-30 so mounting should be the same but I am concerned as it is spec'd at a higher pressure (127 bar). I understand there is a method by adding additional shims to the flow control valve (there is a Youtube video showing the use of a kit for the pump on a Ford Mustang). Since the flow control valve design on the BMW pump is similar I assume this procedure would also work, but my question is by how much extra shimming. Has anyone had experience of such a procedure. I attach a picture of the valve from my pump, you can see where the shims would go between the hex nut (at the LH end) and valve body. I assume the extra shims reduce the spring pressure inside the vale thereby controlling the pressure.

 

You're right in that pump pressure does not directly set boost assist.

The metering valve that DOES might be an integral part of the steering shaft on
an E46- it was on earlier cars, and those are very similar.
This hasn't really come up much on any forums I frequent.

Were I to start adjusting steering boost, I'd pull apart a rack-
I recall that the metering is regulated by torsional deformation
of a valving body, rather than vertical displacement, as in the Fords and such.
And as such, the design of that body sets the amount of deflection it takes
to allow fluid displacement.
It may be possible to modify it, but it's not a simple preload spring...

Frustratingly, BMW does not consider many of the subassemblies
reparable, so parts and pictures are hard(ish) to come by

t

 

These ZF rack tech docs may help.

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Many thanks for the helpful suggestions and useful links to follow. Since my initial post I have looked into the way that the pump and the E46 rack interact. My understanding (and of course I may be wrong) is that the torsion bar inside the vertical shaft of the E46 steering rack control valve acts to control the direction of the HP fluid according to which way the steering wheel is turned by directing the fluid to either side of a double acting piston in the rack. The pressure/flow regulating component that I am referring to for the pump is a self-contained valve that screws into the output port of the body of the LF-30 pump and into which the HP hose to the rack is connected. I have seen U-Tube articles (mainly for GM and Ford pumps) where the design of this control valve is almost identical to that of the LF-30 style pump, GM and Ford make available kits that allow you to install shims onto the body of the flow control valve to reduce its working pressure. Although not supported or even discussed by BMW I assume the same procedure would do the same for the LF-30 pump, but that's only my limited knowledge assumption. For GM adding each shim (about 0.5mm thick) reduces the working pump pressure by about 150 psi per shim, this is probably the assumption I will experiment with and hopefully not blow the system apart.