The brief
The Jetta came in with a noise from one wheel that started as a hum and grew into a grind as the speed picked up. There was a vibration through the steering, a slight pull to one side, and then the ABS warning light came on. All of it pointing at a wheel bearing on its way out.
A wheel bearing lets the wheel spin freely while taking the weight of the car at that corner. As it wears, the rolling surfaces go rough, which is the hum turning into a grind, and play creeps in, which is the vibration and the pull. The ABS light is the giveaway: the wheel speed sensor reads off a toothed ring built into the bearing, and once the bearing is loose or that ring is damaged the signal goes haywire and the ABS bows out. A bearing doing all of that has run its course.
The diagnosis
Up on the lift, the wheel on the noisy side spun with a gritty feel and rocked a touch when you pulled it top and bottom, the play you don't want to feel. The toothed sensor ring on the bearing was chewed up, which explained the ABS light. The other side felt fine.
That's a replacement, not an adjustment. A worn wheel bearing only loosens further, and the failure at the end is the wheel binding or the hub going slack at speed, so this one was getting changed now while it was still just a noise.
The work
The brake calliper and disc came off to get at the hub, the axle bolt was taken out, and the worn hub bearing assembly was unbolted and lifted away. A new VAG-spec hub bearing unit went on in its place, the axle bolt torqued to spec, and the brakes reassembled.
Then the ABS fault was cleared from the module and the system checked, with the new toothed ring giving a clean signal again.
A road test confirmed the grind was gone, the steering sat still, the pull was gone, and the ABS light stayed off.
The outcome
No hum, no grind, steering steady, no pull, and the ABS light out for good.
The Jetta went home with that corner quiet and the brakes working as they should. A wheel bearing gives you plenty of warning before it lets go, so acting on the noise meant a straightforward swap rather than a wheel problem at speed.