Increasingly vague steering

Getting a lot of vague slack on steering wheel. All the wheel bearings OK and new drop arm last year. Opened bonnet and grasped the knuckle joint of the steering rod. With engine off I can turn this either way to make steering wheel move about 20 degree each way, with no wheel movement. Guess it is a worn steering box? Is there any adjustment or is is replace>

There is adjustment available on the steering box but I would check the nut that secures the drop arm to the steering box output shaft as you have just recently had some work done there. I had a recon box fitted as part of a chassis replacement and the locking washed had not been hammered over. The steering got progressively worse (really quite scary). I had a look an found the drop arm had slipped down the shaft. Once fully tightened the steering returned to normal (ie only a bit vague).

Good advice above..There is adjustment on the top of the box, locknut with allen key bolt inside. Adjustment must be made with wheels straight ahead. It is important not to turn the allen bolt down tight, only until it makes contact inside and then back off a tad.

Thanks both, will take a look when it stops raining..................