This is a repost of LAWLence's Z3 Steering Rack Retrofit:
Hi All,
I'm putting this DIY together as there is quite a bit of misinformation out there regarding what steering racks work in the E46. he most prevalent route that E46 M3 owners take is installing a ZHP/330i steering rack. BMW 3 series racks have had the same fitment for over 20 years from the E30 to the E46 model.
My favorite rack out of all the BMW racks is the Z3 rack which features a linear, fast ratio. All other compatible racks that are worth putting into our cars have a progressive ratio; slower in the middle and faster as you turn more. BMW decided to put these on all the M cars for high speed straight line stability, but for those of us who want more just-off-center response (read: track and auto-x goers), a linear rack with a low ratio is the way to go. While the Z4 M Coupe rack has a lower overall ratio than the Z3 rack, it still exhibits the same lazy just-off-center feel due to being a progressive ratio rack. Not to mention the Z3 rack is commonly available at 1/3-1/4 the price of a Z4MC rack.
First, lets examine the differences between the Z3 rack and a stock M3 rack.
The Z3 rack features a plated steel body that is fitted to an aluminum gear housing. There are some subtle differences in ancillary mounting locations, but the rack itself bolts onto the front subframe without any modification. The hose and banjo bolt locations and sizes are exactly the same, so you can reuse all the stock plumbing. When purchasing a Z3 rack, look for one that came out of a non-M from 1996-2002. The Z3M racks are just E36 M3 racks and are not what you're looking for.
The E46 rack has a full aluminum body. As a result, the steel bodied Z3 rack is 3lbs heavier, although the weight is so down low that you will not feel the difference. The last difference is that the E46 achieves pressure equalization in the boots through the tie rods. There is a groove cut in the threads which leads to a hole in the rack all the way to the other side. The Z3 rack has a rubber crossover tube that achieves the same purpose. It fits in with a simple o-ring press fit, so make sure it is secure before installation to avoid any unwanted dirt or fluids entering the rack.
I believe the overall length of the Z3 rack is longer than stock as my car ended up with more toe out after it was installed, but the adjustment to bring it back to spec was well within the adjustment range of the stock tie rods.
On to the swap.
Parts needed:
(1) 32131095575 - Z3 Steering Rack
(2) 32411093596 - 14mmx20mm (IDxOD) washer
(2) 32411093597 - 16mmx22mm (IDxOD) washer
(2) 32211139786 - E36 Steering rack boots
(2) E36 rubber boot donuts
(2) Quart/Liter Dexron III ATF
(1) 2.5" Hose clamp
A few zip ties
Red threadlock (if you didn't get new coupler bolts)
Optional parts:
(1) 32112228785 - Left tie rod
(1) 32112228786 - Right tie rod
(1) 32306752957 - Steering coupler - up to 04/2001; 32301094703 from 04/2001 onward
(1) 32416852470 - M16 x 28 Hollow Bolt
(1) 32416781261 - M14 x 1.5 x 27.4 Banjo Bolt with check valve
(2) 32306778609 - M8 x 33 E10 Steering Coupler bolts
Tools needed:
Jack
(2) Jack stands
22mm socket
19mm socket
15mm socket
10mm socket
Large adjustable wrench
16mm wrench
13mm wrench
E10 External Torx Socket
Various wobble extensions
Ratchet
Flat head screw driver
Wire cutters
Funnel
Fluid drain pain
Beer
Torque Specs:
Steering rack to subframe - 38 ft-lbs
E10 coupler bolt - 16 ft-lbs (hand tight)
Tie rod to steering rack - 74 ft-lbs
Aluminum subframe brace/underplate: 43.5 ft-lbs plus 45-90 degree turn, torque to yield
22/16mm banjo bolt - 30 ft-lbs - enough to compress the crush washers and no more. Bolts are hollow and can snap.
19/14mm banjo bolt - 23?? ft-lbs - enough to compress the crush washers and no more. Bolts are hollow and can snap.
Tie rod lock nut - 33 ft-lbs
Outer tie rod - 48 ft-lbs
I don't have photos for every step as some of them are self explanatory.
You will also retain your stock tie rods. If yours are worn or have more than 100k miles, now would be a good time to replace them.
The first step will be to safely lift your car. Remove the plastic splash panel. Remove the aluminum belly pan/reinforcement plate. Remove both front wheels.
Make sure your steering wheel is centered and locked in position (very important).
Remove the crimp clamps on the boots with a center punch or flat head screw driver. Just stick it through the opening and pry/twist, and the clamps should come apart once you've released the tension this way. Discard these as they are not reusable.
Next, loosen the toe adjustment nut on the tie rod. Slide the boot off the steering rack. Separate the inner tie rod from the steering rack with the adjustable wrench. Separate inner tie rod from the outer tie rod, and remove the boot completely.
You will be replacing this boot with the E36/Z3 component as well as the rubber donut that the boot clamps to. The E46 boots will not fit the new rack as they are too large in diameter. The boot should slide over the inner tie rod down the line. Swing the tie rods out of the way for more room to work.
(E46 boot still attached)
Open up the engine bay and locate your power steering reservoir. It is located under the intake elbow. You may need somebody with skinny arms to reach down or remove the airbox and intake elbow to unscrew the cap. Drain the fluid inside with a turkey baster or suction pump.
I used a MityVac for this. If you can't drain it from the top, follow the next steps and let it drain from the bottom (it will take longer).
Next, remove the upper and lower banjo bolts retaining the pressure lines. They are 22mm and 19mm respectively. Use a wobble extension or u-joint to make sure the socket is square on the bolts--you do NOT want to strip these! Make sure you have something under the car to catch all of the remaining power steering fluid in the lines.
Here are the banjo bolts removed with new copper washers. The washers go on each side of the banjo fitting.
Take a beer break. All German all the time for me!
The next step is to remove the steering guibo. The E10 torx bolts here sit at an odd angle, so you'll need a couple of wobble extensions to get the socket square on the bolts. Remember, we locked the steering wheel in the center position, so you do not want to disturb that by rotating the column just to gain better access to these bolts. The bolts need to come out completely as they go through a groove in the lower steering column as well as the steering rack spline. You will not be able to remove the coupler until the bolts are fully removed.
Coupler removed. If you have difficulty removing it from the splines, try some PB blaster and a small pry bar. Make sure not to damage the housing or the splines if you want to keep or sell your rack! I think I used the subframe as a fulcrum point. It doesn't take much to get the splines moving, although my car is a California car. You will want to use thread locker when you reinstall the torx bolts down the line.
New guibo. I highly recommend a new unit if your car has more than 80k miles. It reduces the on-center dead spot significantly. This did as much to help steering response as the rack itself. Mine showed some minor cracking but a significant amount of flex compared to the new unit with 125k on the clock.
Next, unbolt the two long bolts that go through the subframe. The nuts on top are 16mm, the bolts are 15mm. Make sure you also remove the 10mm M6 bolt holding the power steering line to the housing. I forgot to do this before pulling the rack forward, and this happened! Oops, at least the line was okay and did not suffer any damage.
Back to the bench. We will not be reusing the spline dust cap from the E46 rack. The spline shafts are different between the two units. The E46 spline is longer and accommodates the dust cap with a bevel on the top. Your Z3 rack should have come with a dust cap already which we will reuse.
I suggest using a 3-jaw puller to remove the dust cap. We need the E46 cap as a reference to center the steering rack. There is a notch molded in the E46 cap that indicates the rack is centered, and the "shark fin" portion of it locates the coupler/guibo in relation to that point. We will need to mark the Z3 dust cap where the "shark fin" is on the E46 cap as a reference.
Z3 rack no bevel. The Z3 rack is about 1/2" shorter, but the lower steering column is telescopic and has enough slack to make up for the difference.
Z3 rack, molded mark to indicate center. Measure the rack on both ends to center it, and then put the dust cap on with the mark corresponding to the mark on the housing
Mark the Z3 dust cap
Orient the guibo with the gap/slot facing the angle at which you marked where the "shark fin" is supposed to be. Put thread locker on the E10 torx bolt, and torque coupler to spline shaft to spec.
Next, fit the steering rack onto the car. Your best bet will be to first put in the passenger side bolt and loosely put the nut back on top. This will allow the rack to "swing" into position such that there is some play for the lower steering column to go back into the coupler. The steering column is retractable, to take advantage of that for extra clearance. Bolt everything back up as installation is the reverse of removal. Make sure to secure the boots with the zip ties--use some pliers to pull them taught.
The Z3 rack as I mentioned is missing the M6 tapped hole for the "U" hose. I just zip tied the bracket to the steering rack. This has worked fine for me for years on my old Z3 M Coupe, but you can use a hose clamp for a more secure mount. If someone can chime in with a better solution, please do so.
Stick the funnel in the reservoir (a skinny funnel works best). Fill up the reservoir, and turn the car on (remember to take car out of gear). Turn the steering all the way left and right several times to bleed air in the system. Top off reservoir as necessary. You may hear some squealing/groaning noises which is normal until all of the air is bled. I used Castrol ATF to fill up my rack, but any Dextron III will work. I did not need the 2nd bottle at all, but some members have reported that they did. My rack was full of ATF when I received it, so that may account for the discrepancy.
Align the car to your liking, and enjoy your faster and better steering rack!
I took the car to the track the very next day after installing this, and it was a night and day difference. I never had to take my hands off the steering wheel even through tight chicanes. There are a lot of naysayers that say the car will be darty on the freeway. This is nonsense and is attributed to a worn guibo or alignment issues. My car tracks straighter than ever with the Z3 rack and new guibo!
As a side note, I did also install the TMS rack stop kit for the E36 since I am planning on routing brake duct hoses behind the wheels. This greatly increases the turning radius and is not recommended for a street car at all as you will be making 3 point turns to do a simple parking maneuver. It reduces the Z3 rack to about 2.1 turns instead of 2.5. If you want to use the rack stops, make sure you press fit them prior to putting the rack back on the car. It's 10000x easier with the rack out of the car and no other components blocking a hammer swing!
Hope this DIY is helpful. I welcome your input, and I will make updates and adjustments as necessary. If you guys find a better method for a particular step or have any tips, please share!
Hi All,
I'm putting this DIY together as there is quite a bit of misinformation out there regarding what steering racks work in the E46. he most prevalent route that E46 M3 owners take is installing a ZHP/330i steering rack. BMW 3 series racks have had the same fitment for over 20 years from the E30 to the E46 model.
My favorite rack out of all the BMW racks is the Z3 rack which features a linear, fast ratio. All other compatible racks that are worth putting into our cars have a progressive ratio; slower in the middle and faster as you turn more. BMW decided to put these on all the M cars for high speed straight line stability, but for those of us who want more just-off-center response (read: track and auto-x goers), a linear rack with a low ratio is the way to go. While the Z4 M Coupe rack has a lower overall ratio than the Z3 rack, it still exhibits the same lazy just-off-center feel due to being a progressive ratio rack. Not to mention the Z3 rack is commonly available at 1/3-1/4 the price of a Z4MC rack.
First, lets examine the differences between the Z3 rack and a stock M3 rack.
The Z3 rack features a plated steel body that is fitted to an aluminum gear housing. There are some subtle differences in ancillary mounting locations, but the rack itself bolts onto the front subframe without any modification. The hose and banjo bolt locations and sizes are exactly the same, so you can reuse all the stock plumbing. When purchasing a Z3 rack, look for one that came out of a non-M from 1996-2002. The Z3M racks are just E36 M3 racks and are not what you're looking for.
The E46 rack has a full aluminum body. As a result, the steel bodied Z3 rack is 3lbs heavier, although the weight is so down low that you will not feel the difference. The last difference is that the E46 achieves pressure equalization in the boots through the tie rods. There is a groove cut in the threads which leads to a hole in the rack all the way to the other side. The Z3 rack has a rubber crossover tube that achieves the same purpose. It fits in with a simple o-ring press fit, so make sure it is secure before installation to avoid any unwanted dirt or fluids entering the rack.
I believe the overall length of the Z3 rack is longer than stock as my car ended up with more toe out after it was installed, but the adjustment to bring it back to spec was well within the adjustment range of the stock tie rods.
On to the swap.
Parts needed:
(1) 32131095575 - Z3 Steering Rack
(2) 32411093596 - 14mmx20mm (IDxOD) washer
(2) 32411093597 - 16mmx22mm (IDxOD) washer
(2) 32211139786 - E36 Steering rack boots
(2) E36 rubber boot donuts
(2) Quart/Liter Dexron III ATF
(1) 2.5" Hose clamp
A few zip ties
Red threadlock (if you didn't get new coupler bolts)
Optional parts:
(1) 32112228785 - Left tie rod
(1) 32112228786 - Right tie rod
(1) 32306752957 - Steering coupler - up to 04/2001; 32301094703 from 04/2001 onward
(1) 32416852470 - M16 x 28 Hollow Bolt
(1) 32416781261 - M14 x 1.5 x 27.4 Banjo Bolt with check valve
(2) 32306778609 - M8 x 33 E10 Steering Coupler bolts
Tools needed:
Jack
(2) Jack stands
22mm socket
19mm socket
15mm socket
10mm socket
Large adjustable wrench
16mm wrench
13mm wrench
E10 External Torx Socket
Various wobble extensions
Ratchet
Flat head screw driver
Wire cutters
Funnel
Fluid drain pain
Beer
Torque Specs:
Steering rack to subframe - 38 ft-lbs
E10 coupler bolt - 16 ft-lbs (hand tight)
Tie rod to steering rack - 74 ft-lbs
Aluminum subframe brace/underplate: 43.5 ft-lbs plus 45-90 degree turn, torque to yield
22/16mm banjo bolt - 30 ft-lbs - enough to compress the crush washers and no more. Bolts are hollow and can snap.
19/14mm banjo bolt - 23?? ft-lbs - enough to compress the crush washers and no more. Bolts are hollow and can snap.
Tie rod lock nut - 33 ft-lbs
Outer tie rod - 48 ft-lbs
I don't have photos for every step as some of them are self explanatory.
You will also retain your stock tie rods. If yours are worn or have more than 100k miles, now would be a good time to replace them.
The first step will be to safely lift your car. Remove the plastic splash panel. Remove the aluminum belly pan/reinforcement plate. Remove both front wheels.
Make sure your steering wheel is centered and locked in position (very important).
Remove the crimp clamps on the boots with a center punch or flat head screw driver. Just stick it through the opening and pry/twist, and the clamps should come apart once you've released the tension this way. Discard these as they are not reusable.
Next, loosen the toe adjustment nut on the tie rod. Slide the boot off the steering rack. Separate the inner tie rod from the steering rack with the adjustable wrench. Separate inner tie rod from the outer tie rod, and remove the boot completely.
You will be replacing this boot with the E36/Z3 component as well as the rubber donut that the boot clamps to. The E46 boots will not fit the new rack as they are too large in diameter. The boot should slide over the inner tie rod down the line. Swing the tie rods out of the way for more room to work.
(E46 boot still attached)
Open up the engine bay and locate your power steering reservoir. It is located under the intake elbow. You may need somebody with skinny arms to reach down or remove the airbox and intake elbow to unscrew the cap. Drain the fluid inside with a turkey baster or suction pump.
I used a MityVac for this. If you can't drain it from the top, follow the next steps and let it drain from the bottom (it will take longer).
Next, remove the upper and lower banjo bolts retaining the pressure lines. They are 22mm and 19mm respectively. Use a wobble extension or u-joint to make sure the socket is square on the bolts--you do NOT want to strip these! Make sure you have something under the car to catch all of the remaining power steering fluid in the lines.
Here are the banjo bolts removed with new copper washers. The washers go on each side of the banjo fitting.
Take a beer break. All German all the time for me!
The next step is to remove the steering guibo. The E10 torx bolts here sit at an odd angle, so you'll need a couple of wobble extensions to get the socket square on the bolts. Remember, we locked the steering wheel in the center position, so you do not want to disturb that by rotating the column just to gain better access to these bolts. The bolts need to come out completely as they go through a groove in the lower steering column as well as the steering rack spline. You will not be able to remove the coupler until the bolts are fully removed.
Coupler removed. If you have difficulty removing it from the splines, try some PB blaster and a small pry bar. Make sure not to damage the housing or the splines if you want to keep or sell your rack! I think I used the subframe as a fulcrum point. It doesn't take much to get the splines moving, although my car is a California car. You will want to use thread locker when you reinstall the torx bolts down the line.
New guibo. I highly recommend a new unit if your car has more than 80k miles. It reduces the on-center dead spot significantly. This did as much to help steering response as the rack itself. Mine showed some minor cracking but a significant amount of flex compared to the new unit with 125k on the clock.
Next, unbolt the two long bolts that go through the subframe. The nuts on top are 16mm, the bolts are 15mm. Make sure you also remove the 10mm M6 bolt holding the power steering line to the housing. I forgot to do this before pulling the rack forward, and this happened! Oops, at least the line was okay and did not suffer any damage.
Back to the bench. We will not be reusing the spline dust cap from the E46 rack. The spline shafts are different between the two units. The E46 spline is longer and accommodates the dust cap with a bevel on the top. Your Z3 rack should have come with a dust cap already which we will reuse.
I suggest using a 3-jaw puller to remove the dust cap. We need the E46 cap as a reference to center the steering rack. There is a notch molded in the E46 cap that indicates the rack is centered, and the "shark fin" portion of it locates the coupler/guibo in relation to that point. We will need to mark the Z3 dust cap where the "shark fin" is on the E46 cap as a reference.
Z3 rack no bevel. The Z3 rack is about 1/2" shorter, but the lower steering column is telescopic and has enough slack to make up for the difference.
Z3 rack, molded mark to indicate center. Measure the rack on both ends to center it, and then put the dust cap on with the mark corresponding to the mark on the housing
Mark the Z3 dust cap
Orient the guibo with the gap/slot facing the angle at which you marked where the "shark fin" is supposed to be. Put thread locker on the E10 torx bolt, and torque coupler to spline shaft to spec.
Next, fit the steering rack onto the car. Your best bet will be to first put in the passenger side bolt and loosely put the nut back on top. This will allow the rack to "swing" into position such that there is some play for the lower steering column to go back into the coupler. The steering column is retractable, to take advantage of that for extra clearance. Bolt everything back up as installation is the reverse of removal. Make sure to secure the boots with the zip ties--use some pliers to pull them taught.
The Z3 rack as I mentioned is missing the M6 tapped hole for the "U" hose. I just zip tied the bracket to the steering rack. This has worked fine for me for years on my old Z3 M Coupe, but you can use a hose clamp for a more secure mount. If someone can chime in with a better solution, please do so.
Stick the funnel in the reservoir (a skinny funnel works best). Fill up the reservoir, and turn the car on (remember to take car out of gear). Turn the steering all the way left and right several times to bleed air in the system. Top off reservoir as necessary. You may hear some squealing/groaning noises which is normal until all of the air is bled. I used Castrol ATF to fill up my rack, but any Dextron III will work. I did not need the 2nd bottle at all, but some members have reported that they did. My rack was full of ATF when I received it, so that may account for the discrepancy.
Align the car to your liking, and enjoy your faster and better steering rack!
I took the car to the track the very next day after installing this, and it was a night and day difference. I never had to take my hands off the steering wheel even through tight chicanes. There are a lot of naysayers that say the car will be darty on the freeway. This is nonsense and is attributed to a worn guibo or alignment issues. My car tracks straighter than ever with the Z3 rack and new guibo!
As a side note, I did also install the TMS rack stop kit for the E36 since I am planning on routing brake duct hoses behind the wheels. This greatly increases the turning radius and is not recommended for a street car at all as you will be making 3 point turns to do a simple parking maneuver. It reduces the Z3 rack to about 2.1 turns instead of 2.5. If you want to use the rack stops, make sure you press fit them prior to putting the rack back on the car. It's 10000x easier with the rack out of the car and no other components blocking a hammer swing!
Hope this DIY is helpful. I welcome your input, and I will make updates and adjustments as necessary. If you guys find a better method for a particular step or have any tips, please share!
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