Last update: Dec 26 2016
The electric power steering pump is a from a Toyota MR2, 3rd generation. The part number is 4431017060. I got information for using this pump at honda-tech.com, diyelectriccar.com, and simonfamily.us/FocusEV/.
The electric connectors are expensive at about $55, so try to get them with the pump.
|90980-12068||Large connector housing||1|
|90980-10897||Middle connector housing||1|
|90980-10942||Small connector housing||1|
|82998-12500||Large connector pigtail||2|
|82998-12440||Middle and small connector pigtail||3|
The pump shares the bridge with the motor controller. One of the pump's three mounting holes is at a bit of an angle. A small clip converts from Subaru flatland to Toyota slantyville. It is 1/8in aluminum bar bent into a U shape, then subjected to power sanding.
The Toyota MR2 steering pump specifies right on the cap to use Toyota Power Steering Fluid EH, part number 08886-01206. So that's what I used.
Draining the fluid is simple. Remove the jack up plate (aka support arm), unhook the exposed hose at the LH end, turn the steering wheel slowly. To replace the fluid, fill the tank half way, turn the steering wheel, run the pump, wait a half hour and repeat until no bubbles appear in the tank.
Replacing the jack-up plate presented a bit of a puzzle. The service manual specifies a preposterous torque value of 52 ft·lb (T9) for the middle four M8 bolts. By contrast, the specification for the outer M10 bolts is 22 ft·lb (T3). The 2002 service manual specifies 14.5 ft·lb (T1), for the corresponding middle four bolts, which seems reasonable.
The new Toyota pump is in a different location and has a different thread size output than the Subaru pump. PIRTEK fabricated new lines. They cut the fittings from the bottom end of the existing lines and brazed them to some fittings that attach to new soft lines. The high pressure line has a new banjo fitting sized M16x1.5 for the Toyota pump. The Subaru pump is M14x1.5.
Rotating the plastic tank on the pump 90° counterclockwise routed the hoses a little better.
Power for the pump comes directly from the 12V battery through a 50A self resetting circuit breaker then through a 50A relay that is energized when the ignition is switched on. These components are mounted between the battery and pump, to keep the wires short.
I measured the pump current draw using a 100A ammeter.
|Idle less than 1 minute||6.2A|
|Idle 1-2 minutes||3.9A|
|Idle more than 2 minutes||2.3A|
The steering pump normally receives the vehicle speed sensor (VSS) signal on connector P7 pin 2. I left the VSS pin unconnected. I think the pump uses the VSS primarily for deciding when to put the pump into a lower power mode for saving energy. The steering feels normal without the VSS connection.