Servicing a Steering Box

Greasing/Oiling your Kingpins/Trunnions

Vague steering, finding your cars wanders left or right when trying to travel in a straight line? Well your steering box needs to be adjusted and/or lubricated. Unusually heaving steering? Then your kingpins/trunnions need lubricating.

You will need the correct size spanners to unlock the lock nut on the adjusting screw and to open the top up bolt. A flat-head/slot screwdriver and the correct grease/oil. A grease/oil gun.

With the wheels pointing straight ahead and standing outside the car move the steering wheel from left to right and watch the movement of the front wheels. If the steering wheel moves and the wheels do not then adjustment is needed.

Check for oil leaks and if necessary replace seals. If will entail the removal of the steering box.

Clean any dirt on the steering box with WD40, a soft wire or old clean paint brush and clean lint-free cloth.

Undo the lock nut and turn the adjusting screw clockwise until you feel the slack has just been eliminated then rock the steering wheel from right to left. The front wheels should turn in unison. Do not over tighten the adjusting screw.

Retighten the lock nut while holding the adjusting screw with the screwdriver.

Check the steering box for oil and top up if necessary.As a rule the level should be about 12mm (1⁄2 in.) below the filler hole.

If it is possible to push or pull the (input) shaft then the bearings need adjusting. Either tighten the end screw cap and the end of the steering box or take off the endplate and remove a shim or two (beware of oil loss) until the movement has stopped. Do not overtighten.

With the wheels removed and the car safely up on axle stands (I always leave my trolley jack raised under a cross member for added safety) turn the steering wheel from side to side if there is resistance then your kingpins/trunnions may be seizing up.

Clean the area around the grease nipple with WD40 etc. and using the correct grease/oil squirt in enough grease oil until it oozes out of the seals. Do not clean off this overspill as it helps to protect the seals from dirt etc.

If no grease or oil will go in then your nipples may be seized (very painful!). Using a pin gently press in the little ball bearing in the nipple and clean the tip and try again. If unsuccessful remove the nipple (ouch) and soak overnight in WD40 (safer than petrol or paraffin). If still no luck replace the nipple. Then grease/oil as mentioned above.

Rock the steering wheel from side to side it should be freer. You may need to re-grease/oil again to make sure it has filled the kingpin/trunnion completely.

If there has been no noticeable ease in the steering then you may have to replace your kingpins/trunnions.

Tip: If you are using oil and have not got an oil gun use an oil can (leaver activated) instead a bit messy but it does work.

Useless information: Did you know that the letters EP as in EP80 on your gear oil can stands for Extreme Pressure? Or that SAE stands for Society of Automobile Engineers? Not a lot of people know that! Barry Burke