The two reasons why steering racks fail are fluid contamination and steering pump wear. Your steering rack plays a very important role in your vehicle and is an essential part of allowing you to control it safely. With pressures ranging from 200 to 1200 PSI, it is necessary to know when your steering rack is no longer functioning properly. All it takes is a small leak or contaminated fluid and your rack or steering pump will start to deteriorate leading to reduced steering ability and a possible failure leading to no steering at all. Lack of proper control can prove to be dangerous, especially at higher speeds.
Fluid contamination is the biggest culprit of steering rack failure. We recommend that the installer look at the oil in the old rack they are replacing no matter the reason for replacing the rack. If there is any contamination in the oil, they must replace the pump and hoses as well. If these parts are not replaced, the rack is very likely to fail again. With a few precautions taken, you can ensure a proper steering rack install and avoid potentially dangerous situations. Here is an explanation of the process to ensure you properly install your new steering rack.
Flushing the System
1. When a steering rack fails and is replaced the system must be flushed. Begin by running a gallon of fluid through the pump with the car running and with the hoses hanging in a catch can. The hoses are attached to the new rack and the system is filled with fluid.
- When the car is started the system goes to operating pressure at approximately 200 PSI on the pressure side and 100 PSI on the return side. The hoses, although steel braided, are in fact rubber.
- When the wheel is turned, the system is further pressurized. There is some compressing of the hoses on the inside by this pressure.
- Power steering hoses are made of closed cell rubber. Over time, heat inside of the hoses deteriorate and the closed cells begin to open on the inside surface. As the system pressurizes and depressurizes with each turn of the wheel, the cells of the hose absorb oil and expel oil.
- Power steering fluid is a detergent, as is transmission fluid. Therefore the fluid scrubs and breaks down the hose cells and begins contaminating the "flushed" system. This is similar to a dirty sponge repeatedly squeezed in clean soapy water.
2. Turn the wheel lock to lock repeatedly to check for leaks.
- The system will fluctuate from 1200 PSI to 200 PSI, squeezing the inside of the hose over and over again. The hoses start breaking down immediately if they are the least bit worn out (the closed cells of the rubber being open.
Power Steering Pump
As stated before, there are other variables to take into consideration when installing a new steering rack. Was there debris in fluids when the first steering rack failed? If so, you must replace the steering pump and hoses or risk the likelihood of another failure.
The steering pump should be evaluated for wear. Like the power steering rack, the steering pump runs at a high pressure from 400-900 PSI. When the rack is failing or has failed, the steering pump is still running with little to no oil. The rotor bushing is now wearing faster than it would. There is debris from a failed seal in the rack that will contaminate the fluids and cause more wear. If you only change the steering rack, the steering pump is still worn out and will eventually cause further damage to your new steering rack. Even if the system has been flushed 100%, metal debris will still accumulate as the rotor starts to rub against the sides of the pump housing due to a worn bushing.
Even the slightest amount of contaminations will cause a new steering rack to fail. You can ensure your next power steering rack will last by checking for contamination, flushing your system and replacing your pump and hoses if worn. Avoid spending more time and money on another rack by doing it properly the first time.
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