How do tell if the rack and pinion is bad?

Answer 1

You can take the car up to 100 miles per hour and see if it steers OK or needs constant tiny adjustments. A good car should run as straight as an arrow without the need to constantly tweak the steering wheel.

Finding a suitable road is not that easy so there are now other ways of doing the job. One way is to use the shaker plates which are now becoming popular for European vehicle checks. The vehicle is driven onto the motorized plates which move back and forth applying the sort of forces that the vehicle would experience on a twisty road. Any wear or play should become apparent. Note however that on some brands of car the bottom ball joints are under a great deal of tension and can only be checked for wear when the load imposed by the road spring is removed.

As to the rack, there will usually be a screw that adjusts rack to pinion mesh but in the writers opinion this is never a problem. What is often a problem is leaks from the Power Steering which in Europe means a failure at the annual safety test. The most common problem with a steering rack (Citroen 2CVs excepted) is wear on the rack ends. The rack ends incorporate a ball and socket joint which can wear especially if the car has been run for a long time with unbalanced wheels. To check for wear needs two people. One person wiggles the steering wheel from side to side whilst the other looks at the steering linkages looking for play and listening for clicks. If a rack end is worn the play can be adjusted out but it is a big job as the rack will have to be removed from the car. A service exchange rack is the best bet but the old one can be fixed by an engineer. Before disconnecting the steering it is a good idea to rope the steering wheel to limit its movement. The reason is that nowadays carbon brushes and slip rings tend not to be used to send commands down the steering column. Instead there is a ribbon cable wound like a clock spring and if it breaks its a lot of trouble as the horn will not sound. If the horn does not work the car is guaranteed to fail its annual test.

Reclaiming a rack with a worn end:- There will be a cap nut screwed on and fixed with a steel pin. Where the pin is will have to be discovered by careful inspection. Once found the pin can be drilled out using a drill press. The cap nut can then be unscrewed. After screwing-up (tightening) the cap nut a new hole is drilled and a new steel pin is installed. To stop the pin from falling out, the hole in the cap nut is peened over using a ball-pane hammer. This is really engineering shop work but it is worth doing if a new rack is unobtainable or horribly expensive. If the wheels are balanced properly the repaired rack should last for many years.