I have a 2001 S40 with 160,000 miles. Recently I have noticed a random clunking noise coming from the front right side of the car, as if coming from inside the glove compartment. It happens randomly, without any patterns. It doesn't seem to be related to engine speed or road obstacles (bumps, etc.) either.

When I push down on all four corners of the car, the front right seems MUCH stiffer than the other three. I jacked up the front right corner and noticed that the strut didn't extend smoothly as I raised up the car. The tire come about 3 inches off the ground then suddenly extend. I continue cranking the jack then the same thing, the strut pushes down then stops.

Could I have a hung strut? What else could make the front right strut seem stiffer than it's mate?

 

Sounds like you found the problem. How long since it's been replaced?

The one time I had a noise like yours it was a broken bushing for the anti-sway bar. The difference was that the noise occurred over bumps as the anti-sway bar hit the frame.

When the strut mounts wear out you will notice the top of the strut is not centered in the strut tower. This can cause noise too. It's also a perfect time to replace the struts as you have to take the strut assembly apart to repair the mount.

 

what efforts did u choose to solve up the problem of yours? could u explain to it clearly here

 

Me? The anti-sway bar mounts are aluminum and held to the frame by one 10mm bolt. Secure the car on jackstands, remove the front wheel, lift the front hub to lower the anti-sway bar, remove any remaining bits of the broken mount and replace with new mount. It's very tight getting to the 10mm bolt but it is doable.

The strut mount: Secure car up on jackstands, remove wheel, remove front caliper and secure it (do not remove brake hose), remove support clamp holding brake hose to strut. Remove brake rotor if desired for more room. Remove 2 large nuts/bolts holding strut to the knuckle. Up top remove 3 nuts holding strut mount to strut tower (do not remove large center nut on strut yet). Wiggle strut free of wheel well. Secure strut in vice. Using a strut spring compressor you compress the spring until it's loose. Now use an impact (electric or air, both work fine) to remove the large nut on the top of the strut. Pay close attention to the order and orientation of the strut mount and bearing. Remove it all in order and set it to the side. Now grab your new strut, secure it in the vice, and place the compressed spring in place followed by the new parts for the strut mount and bearing. Now partially tighten the large center nut on the strut, release the strut spring, then completely tighten the large center strut nut with the impact. Installation is reverse of removal. Get the alignment of the wheel as close as possible. For perfect alignment you will need a front end alignment.