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N62 Z3 Part 30: Power Steering & Other Upgrades

After sorting out the radiator and cooling system stuff I experienced my first notable failure of the car. I had observed the power steering high pressure line had a little flat spot rubbed into it from the sway bar. It hadn't been an issue before (it's been like that since pretty much my first drive with the power steering), but when I replaced the power steering pump with the recent cooling system work, the line must have settled into a different position.

I drove the car on about a 3 hour excursion and picked a friend up. He wanted to see what it could do so I flogged it on some closed private roads, and one of the times I hit a large bump at around 100mph. Steering immediately felt a little heavier and once I slowed back down I realized I had zero power steering.

I pulled over and topped it up with some p/s fluid I had in the car. Few seconds later I see a huge plume of smoke come out from under the hood... yikes. Immediate thought was the valve cover gasket from last time I did the valve stem seals must not have been seated properly. Power steering pump was whining, and a few seconds later it lost power steering again. Went to an autozone, got some p/s fluid, topped it up in the parking lot. Pump whined, had power steering for a few seconds. Then it went away... I figured either the pump failed, or the rack was completely shot at this point.

Took the highway home, slightly worried the car would burn down due to a crazy valve cover gasket leak, but oddly, there was no more smoke after the initial plume. Got it home and checked it out...

It ends up my high pressure power steering line has failed. There are signs of fluid on the headers too - so I think that plume was the ATF having shot out of the line to the headers. I think the large bump hit the sway bar into the line and craacked the line. I can wipe the line down, and immediately a few drips of ATF comes back out... ATF was everywhere

Decided to take this time to upgrade other components while I was in there and went with E30 M3 control arms. They look amazing and are very light. I'll weigh them vs the stock arms once I get the lollipop bushings off so it's a fair comparison. Plug and play upgrade for non-M Z3's if anyone is wondering...

E30 arms also have different balljoints, solid metal without a rubber isolator whereas E36 arms have a rubber isolator for the balljoints

I also decided to order solid E36 M3 lollipop bushings to pair with them. I didn't want to deviate too much from my "OE" style build, but wanted to tighten up the front just a smidge. I also decided to replace the steering rack "while I was in there"

Also decided to upgrade to an E36 M3 swaybar with HD endlinks, as the bar is a smaller diameter so I figured it would be less likely to rub the line

Stock Z3 control arms

10 lbs 5 oz compared to 4 lbs 2.5 oz for the aluminum arms, pretty significant difference!

Got the replacement steering rack installed as well as the control arms

I had to build a new line so had my box o' power steering stuff out and was poking around it, I found a Z3 power steering pump and started to think that maybe I could retrofit it to the N62 engine. I did so, using an N62 power steering pump pulley, and realized there was another significant benefit to this change which is that instead of the high pressure line exiting the bottom of the pump, on the Z3 pump it goes out the top. So swaybar clearance won't be an issue at all like it was before

It required some minor custom work to be installed on the N62 engine but nothing major. So now it has a new power steering pump, rack and a new high pressure line was fabricated as well

One of the main things to address was the pulley as the N62 pulley sat a bit inboard compared to the Z3 pump, I used some washers as shims under the pulley to get it positioned correctly as well as using longer bolts to mount the pulley to the hub

This is what the old setup looked like with the N62 power steering pump. The high pressure line comes out the bottom of the pump which is where my issue occurred as the sway bar hit the line

With the Z3 pump installed it's a bit tight around the lines, but enough space to get everything in and tightened and tons of clearance around the sway bar now with the high pressure line going out the top

Great news after about 200 miles of driving is that this system seems to work perfect. No more weird steering behavior, no P/S system leaks, everything feels really tight up front with the solid balljoint controls arms :)

I also decided to ditch the foam intake filters and went with paper cone filters, I did not realize how thick and restrictive these foam ones were before. Feels a little peppier at initial throttle tip-in and a more lively at the top of the RPM band too

Think now it's time to start focusing on cosmetics!

Although, maybe that can wait until I put in a 4.8... the saga continues



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