[Serf27]

Here is a DIY on the steering rack replacement.
I did this job today and couldn’t find a DIY, so here we go. Everything pictured is dirty, as steering fluid sprayed all over the place last time I drove it and the car sat outside collecting dust.

You do need to know what you are doing and what you’re looking at to do this.

This was done on a N54 XI. It should be the same for n51/2.
The intercooler was also removed prior to this(for other reasons) so unsure if it has to be removed or not.

This took me about 2.5 hours.

Tools needed:
Jack with block of wood or engine support bar
Ratchet.
10mm socket(maybe a T25 socket if some fasteners are different on your car)
13mm socket
16 mm socket
17mm socket
18 mm socket
19mm socket
22mm socket
16mm wrench
17mm wrench
E10 socket
E12 socket

The only way to remove the rack is to drop the subframe.

With the car jacked up and the front wheels removed…

Step 1: Not pictured- There is a steel plate bolted the subframe with 6 16mm bolts, remove the bolts and plate.

Step 2: There is a small shield on the passenger side of the subframe, near the left dust boot on the rack. It’s held on with 2 10mm bolts, remove the bolts and the shield.

Step 3: Remove the sway bar from the sway bar end links using a 16mm and 17mm wrench.

Step 4: Remove the sway bar from the subframe. The sway bar brackets have 2 13mm bolts on each end.

Step 5: Remove the tie rod ends from the knuckle, the nuts are a size 22mm.
The passenger side came out fine, the driver side needed some…Persuasion.

Step 6: With the sway bar removed, you can remove the rack and pinion bolts.
T12 bolts hold the rack in place, easily accessible and visible on the subframe.
There is just enough room between the engine and subframe to slide a 16mm wrench through and grip the nut holding onto the T12 bolts.

Step 7: Remove the 4 T12 engine mount bolts. The bolts that hold the mounts to the subframe.

Step 8: Remove 1 T10 bolt holding the steering shaft on the rack and pinion.
Straighten your wheels before fully before lifting the shaft off the rack. It will make the install less complicated.

Step 9: Not pictured- There is a plastic coolant line bolted to the subframe. It is held on with 2 T20 bolts and one 10mm bolt. My rack had an odd 10mm bolt, but I believe it should be 3 T20 bolts. Remove all 3 bolts so the line doesn’t break when the subframe is dropped down.

Step 10: Not pictured- The power steering lines are bolted to the subframe with some little rubber mounts/10mm nuts. Remove the 10mm nuts to let the lines hang freely.

Step 11: if you have space, remove the 2 lines that are bolted to the rack and pinion. 1 bolt is a 22mm or 21mm and the smaller bolt is a 19mm.
If you do not have space to remove the lines, remove them when you drop the subframe a few inches.

Step 12: Jack up the engine with a block of wood between the engine/jack. Lift the engine up about 2 inches. You can also use an engine support bar from the top. The jack did not get in my way.

Step 13: Not pictured Remove 6 18mm bolts holding the subframe on. The subframe will be left hanging on suspension components.
You can lower the subframe by hand while removing the bolts, or use another jack to ease it down or use a helper.(WITH the engine already supported on its own)

While lowering the subframe/removing the bolts, make sure the steering shaft comes off freely from the rack. DO NOT rotate the shaft once it’s comes off the splines on the rack.

If not done yet, remove power steering lines from the rack before dropping it too far(it will put stress in the lines) and make sure nothing is getting snagged on the subframe.

Step 14: With the subframe dropped, slide the rack back out of its bracket and slide it out towards the passenger side. You could probably slide it out on either end, I did it from the passenger side.

Some installation tips:
Try to get your new rack centered or positioned in the same way your old one came out. This will avoid any major alignment issues with the steering shaft and steering wheel.

With the new rack on the subframe, insert the rack mounting bolts and nuts while you have access to screw the nuts on by hand.

Raise the subframe up slowly and try to get the power steering line bolts back on before the subframe is all the way up.
The washers on the power steering line banjo bolts DO have a chance of leaking if they are re used. It would be difficult and make a mess if they leaked and had to be replaced. I took the risk and re used mine, they did not leak. It’s up to you to decide whether to change them or not.

If you are re using your tie rods, transfer those over to the new rack.

The steering shaft gave me some trouble. I had to have the subframe almost entirely bolted down before I could slide the shaft half way onto the splines on the rack. Once it was on halfway, I just wiggled it until it was fully seated on the rack.

With all 6 subframe bolts fully installed, slowly lower the engine and line up the engine mounts.
Tighten the rack mounting bolts if they haven’t been tightened yet.
Install the rest of the parts that were removed.

Fill the system with fluid and turn the wheels side to side to bleed any air out of the system.

[e90yyc]

Seriously impressive that you did this in under three hours!

Thanks for posting this too. Looking at doing this job again, and your method is infinitely more appealing to me than fully dropping the subframe.

[Serf27]

Thanks, the car sat for a year because I was dreading doing this job. I was trying to get in and out as fast as possible to be done with it. + the tension on the suspension bushings with the subframe dangling at the bottom added some sense of urgency.

Not the worst job, but not something to look forward to.
Revised the post a bit. Mainly the washers on the banjo bolts. They can leak if they’re re used.