Hi Folks - hoping someone can help please....

Just replaced the power steering pressure & return lines on my 2007 R52.



Also emptied the carbon dust out of the PS pump case.
Put everything back together - bled the system (CHF 11S) - but no power steering :-( :-(.

Looking at ISTA makes me think the pump is running - and that is backed-up by the screwdriver-stethescope to the pump case.


ISTA Live Reading - EHPS - Power Steering

ISTA Live Reading - EHPS - Power Steering

Monitored above values while driving & steering - PWM values didn't change at all, and RPM only very slightly. I would have thought that on full lock that pump would need to work harder, therefores spin faster and consume more power???

Slackened-off the return line banjo bolt very slightly - and it started to drip - suggesting that fluid is circulating. This is also backed-up by the PS reservoir being warm after a run.
I've turned the steering lock-to-lock 20+ times - wheels off the ground, engine running, engine not running - plus driven in tight circles in local car park (parking lot).
Fuse F39 is good.

I guess most likely causes are:

1. blockage in one or both of the new PS lines. (I didn't run oil through them before fitting them. New, but cheap, aftermarket parts - and pressure line had to be bent to fit.)
2. air lock?
3. possible to be fitted incorrectly?
4. coincidental pump malfunction / induced by the pump being 'jolted; during refitting of the case?

I replaced the lines with the subframe off. Not relishing the prospect of trying to take them off to inspect with the subframe in place - but if that;s what needs to be done. Spent a ton of hours on this already.

Any suggestions for next steps?

TIA.

 

The powersteering pump is very simple on these cars. If you hear it whine while turning and even harder when on full lock then the pump is working.

If you need a stethoscoop or ISTA to check if its running it means the pump is dead.

I am assuming the two plugs on the pump are connected.

 

According to ISTA the idle current of the pump should be 8 amp. Yours is 6.5. To me, this suggests the pump isn't getting enough fluid, so maybe check the supply line from the res to the pump.