The most often neglected fluid and filter on the W123 cars is the power steering fluid and power steering filter.

Learn to change yours today, and extend the life of your pump and steering gear box.

  1. Jack up the front of the car so you can turn the steering wheel while the car is stationary.

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  2. To start the process of changing your power steering fluid, you'll need to remove the lid on the pump reservoir.

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    • With the lid removed you can see that this fluid is a bit low, and is also very dark/dirty.

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    • Remove the nut holding down the spring and plastic retainer, if present. On some cars, there is just a spring as shown in the second picture which should be removed.

    • The nut on this car is a 10mm.

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  3. Spread Fixmas Cheer
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    • Now use your fluid extractor, or turkey baster (never use it in the kitchen again!) to remove enough fluid to get easy access to the filter.

    • Dispose of the fluid in your drain pan.

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    • Remove the filter using a pair of needle nose pliers.

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    • See how nasty this is? This may be the original filter, almost 30 years old...

    • Nice fresh filter picture, ready for install.

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    • With the filter out, you can remove the remainder of the fluid in the reservoir.

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    • Install your new filter. Install it with the holes facing upwards, as shown.

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    • Replace the spring, retainer and nut over the filter and tighten down. The spring should still have some room to expand and contract but should be snug.

    • Fill the reservoir to the bottom of the metal rim around the top of the pump housing.

    • This car is getting power steering fluid, instead of automatic transmission fluid. Both are OK. The power steering fluid is clear.

    • Now, turn on the engine. Be sure the car is in park or neutral first. Turn the steering wheel left and right, as far as it will go, a few times to get out any air.

    • Top off the fluid as needed. Never let the pump run dry.

    • If your fluid is very dirty, simply repeat the process of sucking out fluid, putting the filter back in, filling the reservoir, and then running the engine and turning the wheel until it looks clean.

    Great job keep up the good work!

    cbelle1 - Reply


Finish by re-installing the cap and taking it for a test drive.

16 other people completed this guide.

Nicolas Siemsen

Member since: 12/06/2013

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I find this tutorial so simple to follow. I prefer images and text to video. Well done!!!

Holden Belmont - Reply

Holden, I am glad it was helpful! I agree, I usually prefer good pictures and text to a video - no need to rewind when you miss something.

Nicolas Siemsen -

Agreed. Very well done !

susan vernon - Reply

Thank you so much for your detailed guides! What sort of symptoms could we expect if the power steering fluid or filter need replacing?

Angel Jon Camama - Reply

This was so professional; technical writers take notice!

Brian Graham - Reply

Good job plain and simple thank you

Mike - Reply

Question: Why do I need to jack up the car? Can't I just turn the wheels with the tires on the ground?

David Ballard - Reply

You could. However, turning the wheels while the car is on the ground and not moving puts substantial strain on the pump. If the front wheels are hanging freely in the air that is not an issue. Your pump, your car, your choice :) I would jack it up.

Nicolas Siemsen -

Beautifully explained and illustrated.

Thank You for helping our old cars on the road.

Terry Harris

thar1914 - Reply

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