Any assessment of wear to a recirculating-ball or worm-and-sector Steering Box is worth doing after a check of the lubrication condition of the Steering Box, as it is a straightforward job and the Gear Box cannot function properly without clean gear oil being present within the casing.
Find the Filler Plug
The filler plug is on the side of the steering box casing, usually a square-drive or hex bolt type. Pull it and, using a clean finger or wire, check for oil in the cavity below the plug hole. If it feels dry, then low oil levels are probably causing any wear or stiffness noticed.
Check the Correct Oil Type
The majority of older Steering Boxes will require EP90 gear oil, with a few exceptions that will require a different viscosity lubricant or even grease. Always check the Vehicle’s Service Data to confirm what lubricant is required, and make sure that you are topping up with the correct Oil, and not Power Steering Fluid, as this can also cause severe damage to the internal components of the Steering Box.
For Steering Box, see https://westernpowersteering.co.uk/steering-parts/box/.
Inspect Oil Colour and Consistency
Fresh EP90 gear oil is amber in colour and has a freely flowing consistency. The oil that you drain from the Steering Box should be of a similar colour and consistency. Dark brown oil, oil that has a milky consistency or is even gritty in texture is degraded and may contain moisture. Milky oil in particular suggests that a seal has been compromised allowing water to enter the box. A full drain and refill with fresh EP90 gear oil would be appropriate in this case.
Look for Seepage Around Seals
Oil weeping from the input shaft seal or output shaft seal indicates lubrication loss over time. A light film of oil needs to be monitored but any visible drip or even a crust of dried oil on the surface needs to be addressed with a seal replacement prior to refilling the steering box with lubricant. This is also a point to bring up when going over the older mechanical parts of a vehicle for general inspection and maintenance.
After completing the checks above, you should now have an idea of the work that needs completing to get the Steering Box ready for reassembly and return to use on the road.
