How long poly bushings take to break in
Polyurethane bushings can feel stiff and noisy for days to a few weeks of normal driving. A clunk that gets worse is not break-in. It is a loose bolt or a dry bushing.
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Grease what the kit told you to grease
Many poly bushings need the supplied grease on the barrel and the faces before the arm goes back. Installed dry, they squeak until someone takes them apart again. A zerk fitting only helps if the bushing was designed for it.
Torque at ride height
Control-arm bolts tightened with the wheels hanging wind the bushing. Then every driveway is a twist. The usual method is to set the bolts with the car sitting on its wheels, at the torque in the manual.
Give it ordinary miles
A weekend of mixed driving is a fair break-in for a correctly greased, correctly torqued set. They will not become rubber. If you wanted the old quiet, poly was the wrong material.
Chase a growing noise immediately
Squeak: grease. Clunk: something is loose, or the bushing is moving in the shell. Recheck torque after the first heat cycles. Do not wait a month on a wandering car.
Watch for this
- Suspension work changes alignment. Get it checked after the arms are settled.
When to get help
A shop should take over if the car pulls, clunks, or the bolts will not hold torque.