The brief
The 520i's steering wheel had gone loose, with a clunking noise when you turned or went over bumps, and free play at the wheel before the front wheels responded. He brought it in. That kind of slack in the steering is a real safety issue, so it wants checking and fixing. The steering rack is what turns your wheel input into the front wheels turning, a rack-and-pinion gear with the tie rods coming off each end. As it wears, the internal mesh and the inner ball joints develop play, so you get the free play at the wheel, the vague feel, and the clunk as the slack takes up over bumps. A worn rack doesn't recover, and the play affects how the car steers and how the tyres wear, so it needs replacing, with the alignment reset afterwards.
The diagnosis
On the lift the steering was checked with the wheel rocked and the front wheels watched. The play traced into the rack itself, worn internally with slack in the inner joints, not the tie rod ends or the column. The rest of the front suspension checked out. That's a rack replacement, you don't rebuild it on the car, so the call was a complete steering rack, fitted, then a four-wheel alignment to set the geometry right.
The work
The old steering rack was unbolted and removed, and a new genuine BMW-spec rack fitted with new tie rod ends, the steering connected up, every fastener torqued to the manual figures, and the system bled if the power steering called for it. The car went on the alignment rig and the front geometry set to specification so the steering tracks true and the tyres wear evenly. A road test confirmed the steering was tight and precise, no free play, no clunk, the car tracking straight.
The outcome
Tight, precise steering with no free play at the wheel, no clunk over bumps, the car tracking straight, and the alignment set so the front tyres wear evenly. The 520i went home with the steering sorted. A worn rack only gets sloppier and they take handling and tyre life down with them, so changing it and resetting the alignment put the steering back where it should be.
