PhilMGCollins
Member
So some of you may have seen I somewhat recently converted the steering power assistance from electric to hydraulic on my Z4, and all was fine in that respect of swapping/installing the parts etc. Now I'm no expert mechanic so you might read this and think I'm an idiot - and you'd be partially correct! - but I could do with some advice from anyone that's also done the conversion and or knows their stuff about hydraulic steering systems please!
The start of the story goes like this. After installation and first start up, there was no power assistance being provided by the hydraulic system and I just assumed that it was only when driving at parking speeds that this was the case - as the wheel was obviously too heavy when turning at slow speeds but fine when you're going - so I thought that must just be how it feels with the hydraulic assistance (but that's just the nature of unassisted steering lol).
Initially I swapped out some parts, new LF20 pump (as old one was whining), bought a second steering rack etc and nothing helped. Until I realised that I hadn't been bleeding the system before use... DUH! So yeah, I read that turning the steering from lock to opposite lock a few times would work, so tried that and nothing, no improvement.
Eventually I came across a video that suggested a lengthier bleeding process is necessary, where before you turn the rack lock to lock on start up, you jack the front end up, lock it out back and forth for about 5 minutes with the car off, then start it up and lock the steering back and forth again a few times when it's back down on the ground.
This helped the most, I now had hydraulic PAS... or at least, it was provding assistance throughout roughly 80% of the steering angle range. If I went to end of steering on either left or right turns, I'd be met with a lot of resistance (presumably from trapped air still) which would want to kick the steering back about 90 degrees if I were to let it go after trying to hold it at lock. And then immediately after this, I'd lose all power steering again for a few minutes on the drive until it would seemingly kick in again and I'd get the power assistance.
I thought at this point maybe there really is a need for proper ATF, so I drained the system of it's power steering fluid and refilled it with Dexron III ATF as is recommended on places like E46 fanatics/Bimmer Forums etc. I also here took the time to swap back to the first hydraulic rack I got in my kit (as the second one was misaligned horribly and has since buggered the steering angle sensor which is another issue in itself).
But something is still up, and I cannot for the life of me figure out what. It's got the correct fluid, there are no leaks, I've performed the same bleeding procedure as before and now I'm back to zero assistance from the hydaulic system. To me it seems like a bleeding issue, but I can't see any leaks anywhere, there are no bubbles coming up through the reservoir and I'm not losing fluid anywhere.
It's a real disappintment right now, as I have only heard good things about this conversion, yet I can't help but feel it's taken too much time and money and stress and PS fluid spills on my driveway to be worth it. Anyone got any advice before I give up and either go back to the factory electric setup or find a garage that would actually be willing to take on a job involving a modification like this?
The start of the story goes like this. After installation and first start up, there was no power assistance being provided by the hydraulic system and I just assumed that it was only when driving at parking speeds that this was the case - as the wheel was obviously too heavy when turning at slow speeds but fine when you're going - so I thought that must just be how it feels with the hydraulic assistance (but that's just the nature of unassisted steering lol).
Initially I swapped out some parts, new LF20 pump (as old one was whining), bought a second steering rack etc and nothing helped. Until I realised that I hadn't been bleeding the system before use... DUH! So yeah, I read that turning the steering from lock to opposite lock a few times would work, so tried that and nothing, no improvement.
Eventually I came across a video that suggested a lengthier bleeding process is necessary, where before you turn the rack lock to lock on start up, you jack the front end up, lock it out back and forth for about 5 minutes with the car off, then start it up and lock the steering back and forth again a few times when it's back down on the ground.
This helped the most, I now had hydraulic PAS... or at least, it was provding assistance throughout roughly 80% of the steering angle range. If I went to end of steering on either left or right turns, I'd be met with a lot of resistance (presumably from trapped air still) which would want to kick the steering back about 90 degrees if I were to let it go after trying to hold it at lock. And then immediately after this, I'd lose all power steering again for a few minutes on the drive until it would seemingly kick in again and I'd get the power assistance.
I thought at this point maybe there really is a need for proper ATF, so I drained the system of it's power steering fluid and refilled it with Dexron III ATF as is recommended on places like E46 fanatics/Bimmer Forums etc. I also here took the time to swap back to the first hydraulic rack I got in my kit (as the second one was misaligned horribly and has since buggered the steering angle sensor which is another issue in itself).
But something is still up, and I cannot for the life of me figure out what. It's got the correct fluid, there are no leaks, I've performed the same bleeding procedure as before and now I'm back to zero assistance from the hydaulic system. To me it seems like a bleeding issue, but I can't see any leaks anywhere, there are no bubbles coming up through the reservoir and I'm not losing fluid anywhere.
It's a real disappintment right now, as I have only heard good things about this conversion, yet I can't help but feel it's taken too much time and money and stress and PS fluid spills on my driveway to be worth it. Anyone got any advice before I give up and either go back to the factory electric setup or find a garage that would actually be willing to take on a job involving a modification like this?