Subaru Power Steering Systems
It goes without saying that steering, along with brakes, is the most critical system in your Subaru, affecting both safety and driveability. Makers of quality cars mostly use the rack-and-pinion system, which provides the most direct and accurate steering and the most "road feel". This is naturally the system used by Subaru on all their models. As with all Subaru systems, Subaru steering is designed and manufactured to provide maximum safety and control. Subaru steering is direct and accurate, and provides excellent road "feel" to the driver.
Steering systems in early Subaru models, such as the Brumby, were primitive and mechanical, with a direct connection between the steering wheel and the road. These older systems were imprecise, and heavy to operate. Then more sophisticated systems evolved among car makers, using power assistance, via a belt-driven hydraulic pump. A high level of power assistance gives very light steering, but reduces the sensation of contact with the road. Subaru have struck the perfect balance. Just how good Subaru systems are can be measured in the success Subaru vehicles have enjoyed in all kinds of motorsport.
More recently steering systems have evolved from hydraulic to electric power assist. The electric power assist system is simpler, with fewer moving components, meaning lower maintenance costs, and draws less power from the engine, meaning better performance and lower fuel consumption.
Warning: Avoid Second Hand!
Second hand components of any kind are always to some degree an unknown quantity. Flaws often are not evident until the parts are in service. With vital safety systems like steering and brakes, you don't want to discover defects in operation. Steering components might have stress fractures in the metals that are not detectable, and the level of wear is difficult to judge accurately. Never compromise with safety.
Two types of power steering assistance
Type 1—Subaru hydraulic steering As with most modern motor cars until recently Subaru employed a hydraulic steering system, whereby input from the steering wheel was transmitted via the power steering pump, through hydraulic hoses, to the rack, thence by direct tie rod connection to the front wheels. More recently, Subaru, in line with modern developments, has been moving to an electrical system.
Type 2 Subaru electric steering This system incorporates a variable output electric motor directly coupled to the steering rack. This motor is controlled by a computer, which acts on a signal from a torque sensor in the steering column to increase or decrease current to the electric motor providing varying degrees of assistance. This system is fitted to most current Subaru models and will eventually be used across the whole range. While some drivers complain that road feel is diminished, the electric system is inherently more reliable and efficient.
Both power assist systems are integrated into Subaru's Vehicle Dynamics Control system, (VDC) on selected models. The VDC is a computer based system that automatically adjusts suspension brakes, and steering to suit road conditions and driving style.
Subaru Steering System Components
Subaru's steering systems comprise several components. These components are all interrelated in that failure of one component will lead to cascading failure of other components.
Power steering pump
Driven by a belt from the engine, the power steering pump pushes hydraulic fluid into a cylinder within the steering rack to assist steering. There are two types of power steering pump:
Type 1: 1991 – 2001 The type 1 pump uses an integrated power steering fluid reservoir and does not use a suction hose. These pumps have been very reliable with few reported problems, or internal construction issues other than fluid leaks after 5-7 years of service. These pumps are easily serviceable and parts are readily available. The common reported problems with this model are leaking top lids. These lids have a large rubber O-ring which is difficult to replace. Once leakage sets in, many owners choose to replace the pump. These pumps were larger and bulkier than the type 2 pumps and were incompatible with new slimline body designs.
Type 2: 2001 - Current The type 2 pump has a separate remote fluid reservoir and utilises a suction hose at the low pressure end of the system to return fluid to the pump. These pumps are designed by Subaru as non-serviceable items but because of their high replacement cost, after market suppliers have entered the market with new replacement parts. Because the fluid reservoir is remote from the pump, Subaru incorporated a filter at the base of the reservoir. This filter is difficult to access and is often neglected during services. The most common cause of pump failure is blockage of this filter leading to eventual catastrophic pump failure. Damage is cumulative over time and there is little warning of impending failure.
Steering Rack and Pinion
The steering rack is mounted across the engine bay bulkhead and is connected to the front road wheels via tie rods with flexible links. Racks on Subaru models from 1991- 2006 used a four-bolt mounting system with the rack fastened by two bolts at each end of the rack. Later models used a two-bolt system with one end hooked into the bulkhead and the driver's side bolted down. Both systems have proven to be highly durable and reliable, and have provided a positive driving experience for Subaru owners.
Suction hose (Low pressure power steering return hose)
This is the largest hose in the power steering system. It is fitted at the low pressure end of the system and returns fluid to the power steering pump. With age, this hose becomes brittle and porous, causing air to leak into the system. This may produce symptoms that indicate a failing pump. Many unwary owners have been caught out replacing pumps when only the suction hose was required.
Hydraulic hoses ADS replacements
These are the two high pressure hoses that run from the pump to the rack and back to the pump again. With age these become brittle and start to leak around the crimped joints and O-rings. OEM replacements are expensive and usually not in stock and we do not advise fitting second hand replacements. ADS has engineered a solution. We have sourced high quality generic hydraulic hoses, and we crimp these ourselves to suit Subaru power steering applications for a fraction of the price of new OEM replacement hoses.
Diagnosis and repair—tell-tale signs of steering issues
Signs of impending steering failure include:
- Excessive free play in the steering
- "tram-tracking" over uneven surfaces
- Steering pulling to one side or the other
- Inconsistent steering effort from hard to easy
- Unusually heaving steering
- Knocking noises when turning the wheel from one direction then another
- Groaning or squealing noises from under the bonnet while turning the wheel
- Steering rack fluid leaks or smells of hot fluid
Prevention is always better than cure
Because 99 percent of the time, the power steering system does its job quietly and efficiently, owners tend to forget about it and it tends to be neglected. Some of these pumps have filters that are difficult to access and that must be changed. All systems need to be drained and flushed at proper intervals. Properly serviced, your power steering system will give long life and reliability. Neglect will result in premature failure and expensive repair. At ADS we take care of all power steering service requirements at the correct intervals.
"We have all Subaru model power steering parts, new and reconditioned in stock and ready to fit."
All Drive Subaroo Exchange Power Steering Pumps The pump is the heart of the power steering system. It's a complex piece of hydraulic engineering and is very expensive to replace. A failing pump will sometimes make a low, groaning noise or leak fluid. The noise will be louder under load, as when parking. A high pitched sound indicates low hydraulic fluid.
When the power steering pump fails, owners have hitherto been faced with two options: pay around $1200 plus $400 labour for a new OEM Subaru replacement, or buy a second hand unit for $180 that might be as bad as the one it's replacing. This is because no auto parts manufacturer will manufacture or rebuild Type 2 power steering pumps because of their complexity, and the difficulty of obtaining parts. However, we at ADS have developed a rebuilding technique that restores pumps to OEM specifications for around half the price of a new unit. We are able to do this because, as an independent manufacturer and service provider, we have cultivated a reliable network of suppliers in Europe, the United States, and Japan. We are able to find parts when the others give up and direct you to the nearest dealer.
Better than new racks The rack-and-pinion assembly is the most expensive component of the steering system. Once it wears out and starts to leak fluid, owners are usually faced with the choice of either paying $2000 plus $500 labour for an OEM new replacement, or buying a second hand unit that might be little better than the old unit. At All Drive Subaroo we offer remanufactured racks, priced from $595, that that are in effect superior to the OEM new replacement. This is because the factory new racks suffer from pitting in the rack shaft, which tends to abrade the seals, leading to premature failure. In our remanufacturing process these shafts are ground and polished to remove this pitting and ensure consistent diameter from end to end. The process takes two to four hours and results in a mirror-like finish which eliminates pitting and prevents recurrence. After machining, our racks are reassembled with new, improved seals pressed into place and bench tested for quality assurance. An ADS remanufactured rack will perform better and last longer than an OEM Subaru replacement.
there are many parts distributors using after-market Chinese sourced steering components. While these are much cheaper, the quality is poor and they are known to fail prematurely, and perform poorly, affecting driveability. May Subaru drivers have reported poor steering performance after fitting Chinese parts, and have reverted to OEM. Don't take a chance with steering. At ADS we use only genuine Subaru power steering pump and rack components.
"Our Friendly staff at All Drive Subaru are happy to talk to you over the phone, face to face in our facility in Peakhurst or via email or live chat at your convenience"