TL;DR
- What: Replacing the E36’s steering rack with a quicker rack from an E46 (“purple tag”) or a Z3.
- Why: Fewer turns lock-to-lock and a more direct feel.
- The trap: tie-rod venting. Fit the wrong inner tie rods and the rack boots blow off at full lock.
- Difficulty: 3/5
The racks compared
| Rack | Turns lock to lock |
|---|---|
| E36 (non-M) | 3.4 |
| E46 “purple tag” (BMW 6 755 067) | 3.0 |
| Z3 1.9 | 2.7 |
The purple-tag rack is identified by its purple label ending in 067. Confirm the number on the rack itself before buying: E46 racks came with several different ratios.
A quicker rack also makes the car react more sharply to bumps and ruts. That suits a sporty car, but it isn’t free comfort.
Tie rods: the venting trap
When you turn the wheel, one rack boot compresses and the other expands, so air has to pass between them. On the E46 rack, that air passes through vent grooves in the threads of the E46 inner tie rods. Fit non-vented E36 inner tie rods to an E46 rack and the boots are sealed. Turn to full lock, and the compressed boot pops off and exposes the rack seals to dirt.
The usual solutions:
- E46 inner tie rods with E36 outer tie-rod ends (the common combination), or
- E36 inner tie rods with vent grooves added to their threads, as some builders do.
Fit new boots while the rack is out. Use part numbers for the exact combination you choose: look them up by model on RealOEM.
Power steering lines and fluid
- The pressure and return lines from the E36 have to reach the new rack’s ports. Builders commonly report that the E36 pressure line needs careful re-bending to clear the E46 rack. The alternative is a made-to-fit hose kit for this swap. Bend metal lines gently in a vice, so they don’t kink.
- New sealing washers on every banjo bolt: old ones leak.
- Fluid: Bentley specifies Dexron III ATF for the E36 power steering. Check the label on your reservoir and don’t mix fluid types.
Torque values (Bentley)
| Fastener | Torque |
|---|---|
| Steering gear to subframe crossmember (M10) | 42 Nm |
| Steering column universal joint to steering gear (M8, self-locking nut) | 19 Nm |
| Inner tie rod to steering gear | 71 Nm |
| Outer tie rod end to steering arm | 45 Nm |
| Outer tie rod end lock nut | 35 Nm |
| Power steering banjo bolts, M10 / M14 / M16 | 12 / 35 / 40 Nm |
Installation notes
- Centre the rack before connecting the steering column, so the steering wheel ends up straight.
- Check the steering column joint while it’s disconnected: replace a worn flex disc or joint now.
- Bleed the system: fill the reservoir and turn the steering slowly from lock to lock with the front wheels off the ground, topping up as the level drops. Then run the engine and repeat until no more air comes out. Check every banjo joint for weeping.
- Alignment: a new rack and tie rods change the toe. Have the car aligned before driving it hard. See the suspension geometry guide.
