For the bounce test, push down as hard as you can at each corner of the car, let it come back up, repeat again and again until the car is bouncing up and down as much as possible. Then, let the car go and if it continues to cycle up and down three times or more, the struts are worn out and should be replaced.
To check for blown seals on the struts, (oil leaks), look at the part of the strut where the chrome shaft in the middle of the strut is protruding out of the strut body itself. Now look on the strut tube/body below that for areas that are darker than the strut tube, indicating an oil leak. These oil leaks typically also attract road grime and dirt, which covers the oil in caked on blob of dirt.
Most MacPherson struts are worn out by 100,000 miles or so. If they need replacing, a four wheel alignment must also be completed, or the tires will wear out at an accelerated pace.
Advance Auto Parts offers the Monroe Quick-Struts and you can pick them up at your local store-
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