This fitting guide assumes that you check a few things before you remove the old steering rack.
Confirm Speed-Sensitive Steering Is Not Fitted
This requires a rack with a dedicated sensor port. If no speed sensor is listed against your car’s VIN number or in the build stickers, then the portless version of the rack is the correct part for a direct replacement.
There is more on Audi A4 steering rack at https://westernpowersteering.co.uk/vehicles/audi/audi-a4-b7-steering-rack-without-speed-sensor-port.
Check Hydraulic Line Unions Before Removal
It’s also a good idea to check the thread size of the high pressure line unions and return line unions before you remove them from the old rack. It’s surprising how different some racks can be even within similar production dates, and it’s easy to find out that the ones you have are not quite right when it’s too late.
Inspect the Subframe While Access Is Good
When you remove the steering rack, check the subframe mounting points for signs of corrosion as well as the front subframe bushes for any signs of wear. This is far easier to repair when the steering rack has been removed than after it has been installed and torqued down.
Centre the Rack Before Sliding It In
It is worth counting the number of lock-to-lock turns on the new rack, and setting it to halfway, so that when you centre the steering column spline over it, it will be straight.
Bleed the System Carefully After Fitting
Fill the reservoir with fluid and then slowly turn the steering from lock to lock several times while the engine is switched off. Then start the engine and once again top up the fluid and slowly turn the steering from lock to lock several times until the steering feels smooth and there is no air noise any more.
As mentioned earlier, a simple check at each stage will mean a clean job in the end.
