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Rack & Pinion repair can either assist your bottom line or steer your customers away. Many rack & pinions are replaced due to symptoms or obvious failures instead of eliminating the real problem or the root cause of failure. Here are some examples of situations needing special attention to assist your efforts.

Before replacing a rack & pinion due to a fluid leak at the pinion shaft seal always diagnose why. (See figure 1) A pinion shaft seal is not designed to have more than residual pressure. If there is more than residual pressure in the seal area it will allow fluid to leak. Pressure will always find the least amount of resistance and escape. We need to look further than just the obvious to prevent a reoccurrence. The root cause of this problem is usually caused by a restriction in the return line allowing pressure to build up in an area not designed to handle it. Replacing the return line will eliminate the root cause of failure and not allow the replacement unit to leak. Restriction in the return line can also cause noise binding hard steering leakage and/or poor returnability.

1982-1993 General Motors J L & N body vehicles came equipped with center-take-off style rack & pinions. (See figure 2) These applications have a unique difference on how the tie-rods are secured to the unit. During replacement don't forget to re-use the washers use the correct attaching bolts and lock plate. Failing to use all components could cause noise binding or damage to the replacement rack & pinion housing resulting in a very costly mistake or even dangerous situation when driving the vehicle. Following instructions will prevent you from running into this problem.

Figure 2

Here's an issue that will always come back to bite you. After taking the correct measures to replace a rack & pinion unit including flushing and bleeding the vehicle is then sent out for an alignment. The alignment process to set correct toe adjustment usually requires turning the inner tie rod(s) on the rack & pinion. This is when the problem starts. While turning the tie rod(s) the protective boot (bellows) twists and is not seated correctly allowing for expansion and compression of the boot. After several weeks of driving the boot tears allowing water and road debris to enter the rack rusting the rack shaft and damaging the rack shaft seal. Your customer returns with a leaking rack & pinion and you loose the profits that you made on the job.

After replacing a rack & pinion (especially on Ford's applications) you may run into the inherent noise (whining) problems. If you properly flush & bleed the system you should eliminate the possibility of running into this situation. If you are having trouble ridding the system of air you may want to fabricate a De-Vac tool. (See figure 3) Simply purchase a stopper plug the size of the reservoir opening at your local hardware store. Drill a 5/15" hole through the center of the plug. Insert a 5/16" tube about 4-5" long into the stopper plug. Using a hand held vacuum pump apply 15 inches Hg. to the pump reservoir with the engine idling. Cycle the wheel from lock to lock every 30 seconds for approximately 5 minutes while maintaining 15" of vacuum. After 5 minutes shut off the engine and check the fluid level topping it off if necessary. Repeat these steps until air is depleted from the system and the whining noise is eliminated. If air continues to enter the system you may have a defective pressure hose or connection. It is possible for pressure hoses to allow air to be sucked into the system because of the amount of power steering pressure (some applications as high as 2 000 PSI) but not have external leakage. When in doubt always change the hoses. It is impossible to inspect the internal condition of hoses so be safe and replace if suspected or if the vehicle has high mileage.

TIP:Power steering hoses transmit high pressure to the system which may cause the hose to vibrate. If the hose rests against the engine oil pan or vehicle frame it can transmit the vibration resulting in the same whining noise. Carefully move the hose to see if the noise changes. If so route the hose to prevent contact.

Figure 3

Take care when removing the original rack & pinion hoses. Some applications have the same size pressure and return port. Example: 1986-1994 Ford Taurus and Mercury Sables. When installing the replacement unit make sure you don't cross the lines or the steering will turn right to left by itself or turn to one side and lock under pressure possibly damaging the rack & pinion. The same application requires a check valve to be reinstalled in the pressure port of the replacement unit. So don't send it back with the core. (See figure 4) Most rack housings are made of aluminum. Make sure you do not over torque the fittings damaging the threads on the rack and voiding the warranty. On some applications (mostly Ford) the power steering lines are designed to have some flexibility in the connections. If you attempt to stop a leak or overtighten the line to eliminate the movement you will end up stripping the threads. NEVER use teflon tape to try and seal the fittings. Teflon has a tendency to cover the ports or enter the spool valve in the rack causing the unit to fail.

Figure 4

· Always install a power steering filter to protect your investment.

· Always flush the entire steering system.

· Always bleed the system correctly.

· Always torque fittings and attaching bolts to proper specifications.

· Always recommend replacing hoses and belts to complete the job.

· Always follow installation instructions.

A little extra effort to prevent warranties will pump up sales assist your bottom line and seal your future as a professional automotive technician or shop owner in this competitive industry.