The amount of free play (lash) in the steering of a car is a measure of how much slack there is in the steering before the road wheels start to turn. As with so many aspects of car maintenance, there is a small amount that is acceptable, but any amount greater than this can cause problems as the car becomes more and more vague and starts to wander all over the road.
What Counts as Excessive
Sit in the driver’s seat with the engine switched off. Gently move the steering from side to side. More than 25mm to 30mm of rim movement before the wheels start to rotate is excessive.
Check the Lock-to-Lock Count
Turn steering from full lock to full opposite lock slowly and count. Make a note of the result, then check again. If the result is inconsistent or the steering becomes stiff in the middle of the turn, then there is uneven wear within the steering box.
Feel for Tight Spots
Any tight or rough resistance felt as you work through the full lock-to-lock sweep is evidence of worn internal steering box components. The check for free play should not be a means to mask any stiffness felt in the steering mid-way through lock-to-lock turns.
Using the Adjuster Screw
Check the play using the adjuster screw. The screw is located on top of the steering box and is secured with a locknut. Loosen the locknut and turn the screw in a clockwise direction in small increments until the play at the centre of the wheel is reduced to the specified amount. Check the rim movement after each quarter of a turn and stop before any tight spots are felt. A useful reference for Steering Box is https://westernpowersteering.co.uk/steering-parts/box/.
These simple checks will give you an insight into the workings of your steering and can be carried out in a few minutes, prior to an MOT test or a visit to a specialist garage.
