After smelling my power steering fluid and almost throwing up from the horrible smell (2002 4Runner had 63000 miles on it with original PS fluid), I decided to flush the power steering system.
I found that the best way to flush the system was by doing most of the flush with the truck not running, because with the truck running, I found that the fluid comes out way too fast to do a nice controlled flush without running the PS pump dry. Here is the method I used (sorry I didn't get any pictures. We were in a rush. Stated volumes of fluid are in liters - pretty much the same as quarts anyways.)
Jack the truck up to get front wheels off the ground (raise front and rear to keep truck level.) Start with the front wheels centered. Cover your PS pump drive belt with a rag to keep any fluid spills off the belt (just remember to remove it before starting the truck). Remove PS reservoir cap, and use a Turkey baster with a short piece of rubber tubing attached to it to remove as much old fluid from the PS reservoir as possible (approx 1/4L.) Be careful not to damage the fine mesh filter screen located at the bottom of the reservoir.
Locate the return hose on the PS reservoir (it comes in approximately at the middle [vertically] of the reservoir on the passenger side of the truck, and is held on by a spring clamp.) Disconnect the PS return hose from the reservoir (wrap hose in paper towel when you're removing it from the reservoir to catch any leakage.) Cap the stub that the return hose was connected to on the reservoir (I just used a rubber cap that I had laying aroung the garage that fit snugly on the stub.)
Top up the reservoir with new ATF (approx 1/4L), and make sure the cap you installed is not leaking. Wrap end of hose in paper towel again to catch leakage, and tip end of hose down. I pulled the end of the hose down as low as I could without kinking the hose, and it went down just past the bottom of the engine, which allowed me to put the end of it into a drain bucket (my drain bucket was a clear plastic ice cream container that I had marked off in 1/2 liter increments to make it easier to see how much fluid was going into it.)
Get somebody else to start the truck (without turning the steering wheel) while you're watching the return hose in the drain bucket. When an additional 1/4L comes out (really quick - only approx 4 or 5 seconds), turn the truck off quickly (new fluid was coming out of hose by then.) Top up reservoir with new ATF (approx 1/4L.)
With the truck not running, turn the steering wheel to full lock towards passenger's side and hold it there for a few seconds to allow fluid to fill driver's side of steering rack (approx 1/8L of old fluid will come out of return hose.)
Turn the steering wheel to full lock towards driver's side and hold it there for a few seconds to allow fluid to fill passenger's side of steering rack (approx 1/8L of old fluid will come out of return hose.) Top up reservoir with new ATF (approx 1/4L.)
Turn the steering wheel to full lock towards passenger's side and hold it there for a few seconds to allow fluid to fill driver's side of steering rack (approx 1/8L of mostly new fluid will come out of return hose.)
Turn the steering wheel to full lock towards driver's side and hold it there for a few seconds to allow fluid to fill passenger's side of steering rack (approx 1/8L of mostly new fluid will come out of return hose.)
Ensure that the level in the reservoir is below the level of the return stub (if not, turn steering wheel a bit more to drain more fluid until it is). Remove cap from return stub (wrap it in a paper towel as you remove it because there will be some ATF trapped in the stub), and re-install return hose to reservoir with spring clamp. Top up reservoir with new ATF (approx 1/4L.)
Bleed system by starting car and slowly turning from lock to lock five or six times (hold steering wheel tight against lock for 1 or 2 seconds each time) while somebody watches inside the PS reservoir (air bubbles will come out in reservoir, and reservoir level will fluctuate up and down. When most of the air is out, shut off truck, remove it from the jackstands, and lower it to the ground.
Repeat bleed procedure with wheels on the ground by starting car and slowly turning from lock to lock five or six times (hold steering wheel tight against lock for 1 or 2 seconds each time) while somebody watches inside the PS reservoir (air bubbles may still come out in reservoir, and reservoir level may still fluctuate up and down. When all of the air is out, PS system bleeding is complete.
Shut off truck, re-install PS reservoir cap, and check PS level. Add or remove fluid as necessary. Whole job took approximately 45 minutes, and was quite easy.
I found that the best way to flush the system was by doing most of the flush with the truck not running, because with the truck running, I found that the fluid comes out way too fast to do a nice controlled flush without running the PS pump dry. Here is the method I used (sorry I didn't get any pictures. We were in a rush. Stated volumes of fluid are in liters - pretty much the same as quarts anyways.)
Jack the truck up to get front wheels off the ground (raise front and rear to keep truck level.) Start with the front wheels centered. Cover your PS pump drive belt with a rag to keep any fluid spills off the belt (just remember to remove it before starting the truck). Remove PS reservoir cap, and use a Turkey baster with a short piece of rubber tubing attached to it to remove as much old fluid from the PS reservoir as possible (approx 1/4L.) Be careful not to damage the fine mesh filter screen located at the bottom of the reservoir.
Locate the return hose on the PS reservoir (it comes in approximately at the middle [vertically] of the reservoir on the passenger side of the truck, and is held on by a spring clamp.) Disconnect the PS return hose from the reservoir (wrap hose in paper towel when you're removing it from the reservoir to catch any leakage.) Cap the stub that the return hose was connected to on the reservoir (I just used a rubber cap that I had laying aroung the garage that fit snugly on the stub.)
Top up the reservoir with new ATF (approx 1/4L), and make sure the cap you installed is not leaking. Wrap end of hose in paper towel again to catch leakage, and tip end of hose down. I pulled the end of the hose down as low as I could without kinking the hose, and it went down just past the bottom of the engine, which allowed me to put the end of it into a drain bucket (my drain bucket was a clear plastic ice cream container that I had marked off in 1/2 liter increments to make it easier to see how much fluid was going into it.)
Get somebody else to start the truck (without turning the steering wheel) while you're watching the return hose in the drain bucket. When an additional 1/4L comes out (really quick - only approx 4 or 5 seconds), turn the truck off quickly (new fluid was coming out of hose by then.) Top up reservoir with new ATF (approx 1/4L.)
With the truck not running, turn the steering wheel to full lock towards passenger's side and hold it there for a few seconds to allow fluid to fill driver's side of steering rack (approx 1/8L of old fluid will come out of return hose.)
Turn the steering wheel to full lock towards driver's side and hold it there for a few seconds to allow fluid to fill passenger's side of steering rack (approx 1/8L of old fluid will come out of return hose.) Top up reservoir with new ATF (approx 1/4L.)
Turn the steering wheel to full lock towards passenger's side and hold it there for a few seconds to allow fluid to fill driver's side of steering rack (approx 1/8L of mostly new fluid will come out of return hose.)
Turn the steering wheel to full lock towards driver's side and hold it there for a few seconds to allow fluid to fill passenger's side of steering rack (approx 1/8L of mostly new fluid will come out of return hose.)
Ensure that the level in the reservoir is below the level of the return stub (if not, turn steering wheel a bit more to drain more fluid until it is). Remove cap from return stub (wrap it in a paper towel as you remove it because there will be some ATF trapped in the stub), and re-install return hose to reservoir with spring clamp. Top up reservoir with new ATF (approx 1/4L.)
Bleed system by starting car and slowly turning from lock to lock five or six times (hold steering wheel tight against lock for 1 or 2 seconds each time) while somebody watches inside the PS reservoir (air bubbles will come out in reservoir, and reservoir level will fluctuate up and down. When most of the air is out, shut off truck, remove it from the jackstands, and lower it to the ground.
Repeat bleed procedure with wheels on the ground by starting car and slowly turning from lock to lock five or six times (hold steering wheel tight against lock for 1 or 2 seconds each time) while somebody watches inside the PS reservoir (air bubbles may still come out in reservoir, and reservoir level may still fluctuate up and down. When all of the air is out, PS system bleeding is complete.
Shut off truck, re-install PS reservoir cap, and check PS level. Add or remove fluid as necessary. Whole job took approximately 45 minutes, and was quite easy.
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