A failed seal within a recirculating-ball or worm-and-sector steering gear is often overlooked until it has caused enough damage to warrant a full replacement instead of a simple repair.
Oil Weeping Beneath the Casing
As the Steering Box drains out any excess lubrication oil, it will leak out from beneath the casing, typically near the input shaft and output shaft ends, where the seals meet with the rotating shafts. The oil may appear as a damp oily patch or even a small puddle.
Hardened or Cracked Seal Lips
Using the external seal of the Steering Box, for example, look for signs of cracking, or signs of hardening. These signs of wear can be seen by looking close at the rubber lip of the seal, or by removing the seal from the Steering Box casing. Dried out rubber loses its ability to hold pressure.
Stiff or Notchy Steering Feel
This increased friction results in a very hard and unresponsive steering effort – typically worst when performing slow turns at low speeds. Often felt as ‘stiff’ or with ‘notches’ in the return-to-centre action.
Excess Free Play at the Steering Wheel
However once internal pressure drops then there is often increased free play. A useful reference for Steering Box is https://westernpowersteering.co.uk/steering-parts/box/.
Discoloured or Contaminated Fluid
Early signs of internal wear can be ascertained by draining and analysing the internal lubricant. If the fluid is milky, looks to have got grit in it or has gone dark and thixotropic then it is likely that the seal(s) are starting to fail.
By detecting seal failure in time, you can avoid having to go for a full rebuild of the steering box.
