How a Power Steering Pump Works

#1
I thought I'd share my teardown of a power steering pump. Its quite interesting what's inside and how it works!


Here are a few photos of the pump teardown. This is the high pressure line and pump removed:



This is the pressure port union. The two small holes are what fluid travels through:



The flow control valve reroutes excess fluid from the high pressure side to the low pressure side. This controls how much steering boost you get through the steering rack. Mine popped out and flew away before I could get a pic, but here's a diagram:



Removing the pulley:


This is the low pressure inlet:


This is the pump separated into two halves. On the left side is where the action happens, there's a rotor that spins in ecentric cam. The rotor has vanes on it that push the fluid causing the flow.



Here's the rotor removed with the vanes. The vanes are free to move along the slots of the rotor, and therefore are pushed outward against the eccentric cam's shape by centrifugal force.



What's left is the eccentric cam and the main part of the housing, that contains the pockets directing fluid into and out of the rotor:



And that's pretty much all the components inside a Toyota power steering pump:



Enjoy!
 
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