1. Flush power steering pump before connecting hoses. When flushing pump, crank engine only (Do not start engine).
2. Fill pump reservoir with proper power steering fluid. Crank engine and continue to replenish fluid until fluid coming from hose runs clear. Do not allow pump to run without fluid.
3. If possible, have someone turn steering wheel from full left to full right (avoid hitting stops). This helps purge system of dirt and metal particles.
4. Reconnect return hose and fill reservoir to correct level. The system is self-bleeding, and a few turns from left to right should purge all air.
5. Some applications may require vacuum bleeding to purge all air.
6. Proper steering flushing method.
Some Ford pumps are difficult to purge. Result is a “growling” type of noise. Verify that all fittings are airtight by loosening slightly and retightening.
Hoses deteriorate from inside out. Bad hoses can be difficult/impossible to detect from outside inspection, and one rotted hose probably means all are rotted. Even one bad hose can recontaminate the system.
Any one system component can retain contamination from old unit and contaminate replacement unit.
Filters increase life of all components by filtering out particles not removed by flushing procedure and particles caused by every day system wear.
Use only manufacturer-recommended power steering fluid specific to your vehicle.
Refer to manufacturer’s specifications.
Follow the step-by-step, fully-illustrated instructions included with every unit. ALSO follow any specific instructions provided by vehicle manufacturer.
If unit has never been on car, return to store inventory (do not return to manufacturer). Signs to look for:
1. No steering fluid in unit
2. Installation kits unused
3. Unit very clean
4. Paint on or around the cap plugs is unbroken
Signs of improper installation, mishandling and tampering by the installer include:
1. Broken port
2. Cut/torn boots
3. Stripped threads (mounting and/or ports)
4. Rusted rack
5. Broken housing
6. Missing parts
To qualify for possible warranty coverage, the unit must:
1. Have CARDONE date code visible
2. Show no signs of abuse
3. Appear to have been on car
4. Have mounting marks
5. Have all parts returned
1. Warranty void if unit disassembled
2. Remind customer to always return cores in replacement part original packaging
Do not accept unit for warranty if:
1. No CARDONE color code visible
2. No CARDONE paint
3. Unit has missing parts.
The #1 steering problem CARDONE encounters during analysis of customer returns is failure related to contamination in the system. Failure to flush the system correctly can lead to several premature issues such as binding, poor turnability, leaking, hard steering or noise.
The processes below will greatly minimize steering system contamination while also preventing excessive air from entering the system. During the flushing process, the engine is not running at high RPMs. This does not allow air to enter easily into the system, but bleeding must still be performed.
Use this process to properly flush the steering system when replacing any steering component. Remember that skipping a step in the process usually results in a comeback.
NOTE: Some vehicles require minimal bleeding, while others require patience and persistence. Refer to the article titled “Vacuum Bleeding”. Allowing the vehicle to sit for a few hours may allow the air bubble to rise. If unsuccessful, there may be additional O.E. procedures available
Before replacing a rack & pinion due to a fluid leak at the input (pinion) shaft seal, always diagnose why. An input shaft seal is not designed to have more than residual pressure. The pressure and flow is retained within the spool valve, unless higher pressure within the system is causing fluid to push beyond the spool valve and into the input shaft sealing area. It's a simple statement, but pressure will always follow the path of least resistance and eventually escape. In this case, please examine the steering system, in order to find and prevent a recurrence.
One potential root cause of residual high pressure can be a restriction in the return line due to rubber breakdown or internal collapse. This causes back-pressure to build up in the rack & pinion and an input seal leak. Replacing the return line will eliminate this problem. Also remember that restrictions in the return line can also cause noise, binding, hard steering, leakage and/or poor returnability.
Another root cause of input shaft leaks could be line reversal during installation. Many Ford applications have the same fitting size for both the pressure line and return line, so there is a chance that the pressure line was threaded into the return port and vice-versa. If this is done, and the vehicle started, the pressure will be directed through the top of the spool valve and out the input shaft seal. Once this mistake is made, the damage is already done and the unit must be replaced. In order to prevent this, clearly mark the original unit and lines, before removing the unit from the car. Use tags or differently colored paint pens, then transfer the tags or markings onto the replacement unit. 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 below).
A common mistake when a leak occurs is to tighten the lines. However, over-tightening will actually compound the problem by stripping the threads. Since most rack housings are made of aluminum, the soft housing threads will strip away against the steel threads of a fitting. CARDONE supplies new o-rings or Teflon rings with each unit, in order to provide new sealing materials versus using the old and distressed ones. So take the first step to avoid leaks, and always replace the o-rings or Teflon rings. Last, never use Teflon tape as an attempt to seal the fittings. Teflon has a tendency to cover the ports or unwind into the rack spool valve, causing the unit to fail.
Twisted boots on Rack & Pinion systems are an avoidable comeback failure. To keep this from happening the following steps should be taken.
After proper installation of a rack & pinion unit, including flushing and bleeding, the vehicle is then sent for an alignment. In order to set the correct toe adjustment, the inner tie rod(s) on the rack & pinion typically must be turned, and this is when the problem starts.
If the boot clamps are not loosened, the tie rods are unable to turn freely inside the boots (bellows), and the boots will become twisted. Once twisted they no longer move freely with the rack preventing them from expanding and contracting. The boots continue to twist tighter while the vehicle is driven, eventually causing the boots to tear. Water and road debris are then able to enter the rack causing internal rust and damage the rack shaft seal leading to a leak and premature failure.
A rack & pinion, once completely sealed and operating perfectly, is now defective and the vehicle comes back for an avoidable replacement. Therefore, always check the rack & pinion after the car is returned from alignment to make sure the boots are not twisted.
Electronically variable orifice (EVO) steering varies the amount of power steering assist based on electrical inputs to provide the driver with improved road feel at higher speeds, and at the same time providing power assist at lower speeds and during parking maneuvers.
EVO systems utilize information such as vehicle speed, steering wheel position, and steering-wheel turn rate to calculate and deliver optimum assist to match road conditions.
The EVO system uses a solenoid valve attached directly to the PS system pump’s output fitting or the rack and pinion housing. It is electrically controlled by a digital control signal using pulse width modulation (PWM). By varying the amount of "on-time," or duty cycle of the control signal to the solenoid, variable levels of fluid flow and resulting effort levels can be obtained.
Depending on the year and model, the solenoid could be directed by various control modules. A "dedicated" EVO module was used in the earliest versions of this system. Since that time, however, the electronic-brake and traction-control module (EBTCM) has taken over the responsibilities of VES in most GM products.
Vehicle weight, steering design and suspension geometry vary greatly from platform to platform. Seemingly identical cars, with different tire or handling/suspension options, may require slightly different VES behavior. The EVO software is altered to provide ideal assist levels at each speed for this wide variety of vehicles, tailoring the vehicle’s handling "feel" to the car and its intended customer’s preferences. Four or five EVO-module part numbers for the exact same year and model of car are not uncommon.
An enhancement to EVO-VES systems that began to appear in 1992 included a steering-wheel position sensor (SWPS) or handwheel speed sensor (HWSS), depending on the vehicle platform. This sensor has the ability to input steering-wheel position, direction and turn-velocity data into the EVO controller. Using this data, the EVO control module can quickly react to emergency evasive maneuvers. If the driver were to suddenly swerve or change lanes to steer around an object on the highway, the EVO module provides an immediate boost in assist levels, maximizing steering control.
One of the renditions of GM VES systems is known as magnetic speed variable assist (MSVA), or MagnaSteer. MSVA was designed specifically to minimize one of the few negative aspects of EVO type steering systems. EVO systems, at highway speeds, restrict the flow from the power steering pump. This restriction raises internal pump pressures as well as the pump’s belt load on the engine. This additional engine load will have a negative impact on fuel consumption, and will increase exhaust emissions as well.
The first GM MVSA system, dubbed MagnaSteer, was initially used in 1995 on the G-body platform, the Olds Aurora and Buick Riviera. Cadillac also enveloped this MVSA system into their Integrated Chassis Control System in 1996. MVSA became even more popular with its release in GM’s 1997/98 versions of the Pontiac Grand Prix, Olds Intrigue, and Buick Regal W-body platform.
While the EVO-VES systems were a "bolt-on" addition to an existing power-steering system, MSVA requires a specially designed rack and pinion assembly. An electromagnetic coil within the steering rack’s spool valve has the ability to alter the assist/effort levels by varying the strength and direction of a magnetic field.
To simplify the process, the MVSA module directs the current flow to the electromagnet coil in one direction to increase the amount of assist. Reversing the direction of current flow has the opposite effect.
When no current is flowing through the electromagnetic poles, there is a fixed moderate amount of power steering assist, which is the default should trouble arise. This default (zero coil current) will approximately equate to the amount of power assist at 30-40 km-h.
After replacing a rack & pinion or power steering pump, and proper flushing & bleeding processes are performed, air may remain trapped in the system; this is particularly true on Chrysler Minivan and Ford applications. Hydraulic noise, groaning or whining, will plague the installer until the trapped air is purged from the system, and using vacuum is the best and easiest way to pull these small air bubbles out.
Vacuum Bleeder Tools (Special Service Tools), specific to O.E. applications can be found through Tech Service Bulletins on Alldata or Mitchells. However, many aftermarket products are available (see Figure 1 and Figure 2) for a reasonable price. Some models use a reservoir to trap fluid, but this is not necessary to complete the job.
A rubber stopper or plug will be needed to seal off the fill hole of the reservoir. Simply purchase the correctly-sized stopper at your local hardware store. Drill a hole through the center of the stopper and Insert the tubing from the vacuum tool into the stopper (see Figure 3).
Figure 3For large Ford (C2) pumps, use # 2 or # 3 stopper. For small (C3) Ford pumps, use # 10 ½. For Saginaw pumps, use # 7.
Using the vacuum tool, 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 as necessary. Repeat these steps until air has been removed from the system and the whining or groaning 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.
1993 - 2004 Chrysler Group and 1982-1993 General Motors J, L & N body vehicles came equipped with center-take-off (CTO) style rack & pinions. (See figure 2) These applications are unique in the way the tie-rods are secured to the unit. During replacement, don’t forget to re-use the washers, bolts and lock plate. Pay extra attention to the washers, as years of road grime, heat and material breakdown can cause the washers to bond with the boot. If the washers are not used, the bolts will cause extensive damage internally to the housing. If the fasteners listed above, are either lost or damaged, CARDONE has completely new CTO installation kits available for both GM and Chrysler applications, part numbers 22K100 & 22K300, respectively.
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 the instructions above will prevent you from running into this problem.
When a service dealer called his CARDONE sales representative with a concern about his 20-25% steering warranty rate, CARDONE's quality team contacted him to learn more and find the root cause.
They learned that the technician uses a reliable, national brand of power steering fluid that meets CARDONE criteria (see article “Not All Power Steering Fluids Are Created Equal”), while also flushing with new fluid and bleeding the system every time. However, the technician also mentioned that he uses brake cleaner to wash out all the debris and build-up from the inside of the power steering lines/hoses.
This off-the-cuff statement led to further investigation into common automotive cleaning chemicals and the potential effects they could have on the steering system
Brake cleaner was specifically mentioned above, but carburetor cleaner and engine degreaser were additionally explored, as all three are common cleaning chemicals.
Rubber components in a steering system are either Viton or BUNA material; therefore seals of both compositions were spray tested with all three chemicals at 100% concentration. Both the brake cleaner and carburetor cleaner samples began to swell 15 minutes after exposure, however, the engine degreaser had no visual change. The seals were then soak-tested for 24 hours in 100% concentration, and further degradation occurred (see picture). The results of the brake cleaner and carburetor cleaner are both undeniable, but the engine degreaser did not cause significant damage to the rubber.
Testing continued with the presumption that the chemicals would not remain at full strength when power steering fluid was added to the system, as in the case where the hoses are sprayed out. Therefore, new seals were soak-tested for 72 hours in a 10% chemical to 90% power steering fluid mixture. Results were not as dramatic as shown in the photo, but the rubber hardness did degrade. In a power steering system, where dynamic function is key during all ranges of heat, flow and pressure, even small changes in the rubber integrity can cause leaking and premature failure.
The seals seemed to react well against the engine degreaser, but visual appearance is not a viable analysis method, so additional testing will be performed to analyze if any long-term effects occur.
It is understandable that technicians would use brake cleaner and/or carburetor cleaner as a method to clean the system, as both are sold in every parts store across the country, and are known to remove grease and grime better than anything else. However, the attempt to “do some good” can result in the exact opposite.
Therefore, the best advice is to avoid all chemicals completely and simply use the old-fashioned power steering flush method to remove contaminants from the system, as it will avoid introducing foreign elements into the system.