1. Steering Columns

2. Steering column components
Steering wheel
Air bag
Clock Spring
Steering lock plate
Steering angle sensor
Cancel cam
Lock cylinder
Ignition switch
Turn signal switch
Headlight switch
Wiper washer switch
Cruise control switch
Upper steering shaft
Lower steering shaft
Shaft bearings [3]
Tilt housing
Constant velocity joint
Steering coupler

3. Steering columns and crash survivability
The modern steering column is the result of thousands of crash tests.
The information learned from each test has helped thousands of people survive accidents that would have been fatal in older vehicles.
In a crash the steering has to be capable of collapsing from both ends.
This prevents the steering column and shaft impaling the driver’s chest and helps to absorb the kinetic energy of the drivers body.

4. Steering shafts and couplings
The connection between the steering wheel and pinion shaft/worm shaft is normally in three parts.
Upper steering shaft
Spline for steering wheel
Intermediate shaft
Upper steering shaft
Intermediate steering shaft
Steering coupler
Steering coupler
Pinion shaft

5. Steering wheel
The steering wheel is connected to the upper steering shaft via a tapered spline.
Once the steering wheel retaining nut has been torqued the steering wheel can only be removed from the steering shaft by a steering wheel puller.
Two threaded holes on either side of the spline are provided for the puller tool.
Index marks
Steering shaft spline
8mm x 1.25 tapped holes
A pass through hole in the hub allows the electrical connector for the air bag, horn switch and steering wheel mounted switches to connect to the clock spring.

6. Steering shaft constant velocity joint
Intermediate shaft
Upper steering shaft
Nearly all modern cars have tilt wheel type steering columns.
A constant velocity type joint is needed to allow the steering effort to pass through a 0o to 20o angle without the steering being jerky.
The constant velocity joint connects the upper shaft to the intermediate shaft.

7. Intermediate shaft The intermediate shaft is collapsible.
Outer shaft
Upper steering shaft
Inner shaft
The intermediate shaft is collapsible.
The outer shaft is hollow allowing the solid inner shaft to telescope into the outer shaft tube.
Whenever working on a steering column you must be careful to not tap on the ends of the shafts or exert any pressure that might shorten the assembly.

8. Shaft support bearings
Sealed ball bearings
The intermediate shaft and the upper shaft are supported by sealed ball bearings.

9. Steering Coupler
The coupler connects the intermediate shaft to the pinion shaft or worm shaft.
Like the intermediate shaft the coupler also telescopes.
This allows the sub-frame and rack to move on their rubber mounts without passing shock and vibration into the intermediate shaft.

10. Frontal impact forces coupler downward
Steering Coupler
The steering coupler is normally located on the engine compartment side of the firewall.
Frontal impact forces coupler downward
The coupler is mounted at an angle relative to the steering column so that in a severe frontal impact the sub-frame and rack will be pushed downward and under the firewall.

11. Center of joint is ‘D’ shaped to match spline on shaft
Pinch bolt joints
Center of joint is ‘D’ shaped to match spline on shaft
‘D’ shaped spline
Notch in shaft
Steering couplers are normally attached to shafts via a pinch bolt joint.
The joint and shaft are connected by ‘D’ shaped splines.
The pinch bolt passes through the notch in the shaft as a safety mechanism – if the bolt loosens the joint will not separate from the shaft.

12. Outer column
The shafts and bearings are supported by a collapsible steel housing.
Breakaway bracket
Firewall
The housing connects to brackets on the body that can breakaway and slide inward in a crash

13. Outer column
A rubber grommet mounted in the firewall prevents dirt and water from entering the passenger compartment
Plastic boot
A plastic boot located between the steering rack and firewall helps to keep dirt and water away from the grommet.
Grommet

14. Upper column
Upper column tilt bearing
Clock spring
Combination Switch[s]
The clock spring connects the air bag, horn and electrical switches mounted on the steering wheel cover to the vehicles electrical system.
It is mounted to the tilt assembly directly below the steering wheel.

15. Inner sleeve keyed to steering wheel
Clock Spring
The clock spring is a spool of ribbon cable that winds and unwinds as the steering wheel is turned.
Most clock springs can turn about 4 to 5 turns from fully unwound to fully wound.
Inner sleeve keyed to steering wheel
Index marks
To prevent damage to the clock spring it must be centered and removed whenever the steering gear is serviced.
To center the clock spring turn the wheels to straight ahead with the steering wheel at 12 o’clock.

16. Upper column
Upper column tilt bearing
Clock spring
Combination Switch[s]
The combination switch assembly is mounted to the outer face of the tilting assembly.
The combination switch is operated by the stalks on the outside of the steering column.
Some manufactures integrated all the switches into one assembly.
Otherwise there are two switches on either side.

17. Upper column tilt bearing
Tilt assembly
Housing
Upper column tilt bearing
Tilt up spring
The tilt mechanism is spring loaded so that the steering wheel will rise if the lock lever is released by accident.
The lock lever clamps the sides of the tilt assembly to the housing.

18. Plate type steering lock
Lock plate
The steering lock plate is a stamped steel plate that is splined to the steering shaft.
When the ignition key is turned to the lock position the actuating rod pushes a spring loaded locking pint into a notch in the lock plate.
Spring loaded locking pin
Lock plate splined to steering shaft
Actuating rod
Lock cylinder

19. Pawl type steering lock
Pawl gear
Lock cylinder
Steering shaft
Cam
In this type of lock mechanism a pawl gear is machined directly on the intermediate steering shaft.
The locking pin is actuated directly off of a cam on the back of the lock cylinder.

20. Steering locks for keyless ignition
Spring loaded lock pin
Electric motor
Worm gear
Keyless ignition systems use a radio transmitter to actuate the door locks and ignition system and do not have a conventional lock cylinder on the steering column.
To lock the steering system a small electric motor moves the locking pin into and out of the pawl gear when commanded by the BCM or security system control module.

21. Lock cylinder
Mechanical lock cylinders are mounted to the lower section [stationary] of the steering column housing.
The lock cylinder is retained in its bore in the housing by a spring loaded pin.
Inserting a pin punch into a small hole in the housing will depress the lock pin so that the entire lock cylinder can be removed.
The lock cylinder must be in the accessory position to allow the pin to be depressed.

22. Ignition switch
Ignition switches are actuated directly by the lock cylinder or remotely by an actuating rod.
Most modern cars have a direct acting ignition switch bolted the lock cylinder housing.
Remote ignition switches are located on the base of the steering column housing and are actuated by a rod that connects to the lock cylinder at the top of the column.
Remote ignition switches have slotted screw holes that allow the switch to be adjusted.

23. Turn signal cancel cam
Cancel pin on turn signal switch
Combination switch assembly
Cancel cam splined to steering shaft
The cancel cam triggers the turn signal switch to turn off after the turn has been completed.
If the cancel cam is not positioned properly on the steering shaft the turn signals will not cancel correctly.