How would I know if I needed new shock absorbers ? I am getting a strange wear pattern on my tires, even though alignment is good.... could this be the shocks ? Vehicle is a 98 Explorer.

Quoted: How would I know if I needed new shock absorbers ? I am getting a strange wear pattern on my tires, even though alignment is good.... could this be the shocks ? Vehicle is a 98 Explorer.

Tire wear patterns will indicate certain problems, it depends on what kind of pattern you have though.  Cupping(described as a series of dips on one side of the wheel) is a common problem that is caused by worn shocks/struts or other suspension parts such as ball joints. On Explorers I would probably bet you need ball joints if they haven't been replaced. Unfortunately, 90% of the Explorers that I see need ball joints, many even at low mileage.

Because the front ball joints are not under sprung tension like many other trucks, you can check them just like you would check a loose wheel bearing, only with a little more force from top to bottom. IIRC the ball joint spec is .6mm of play before they fail a safety inspection.  Definitely check them, or have them checked!

If your shocks are bad it is sometimes easier to just take a test drive to find out. There are some physical symptoms you can look for too that may present themselves when shocks go bad. The first thing to look for is oil leaking from the shaft seal. If you look at the spot where the shaft comes out of the shock body, and it appears to be wet or oily your shock is leaking. Normally it looks like dark road grime because the oil attracts everything, but it will be on the top of the shock body. But keep in mind that not all bad shocks will leak. You can also check for worn or broken bushings on the top and bottom.

On a test drive, if your car leans too much in a corner, or sinks down low over dips, or dances around/flutters over a series of bumps, then you probably need new shocks.


Hope this helps.

push down on each of the corners of the car.  If it bounces more than once they are going bad.

push down on each of the corners of the car.  If it bounces more than once they are going bad.

Quoted: push down on each of the corners of the car.  If it bounces more than once they are going bad.

That's a good one too.

Quoted: push down on each of the corners of the car.  If it bounces more than once they are going bad.

Yes I tried this, but with the stiffness of the suspension on such a heavy truck, its difficult to get enough movement to draw a definitive conclusion. Maybe I should find someone who weighs more than 300lbs to do this test... should be able to find a few volunteers here .

Quoted: Quoted: push down on each of the corners of the car.  If it bounces more than once they are going bad. Yes I tried this, but with the stiffness of the suspension on such a heavy truck, its difficult to get enough movement to draw a definitive conclusion. Maybe I should find someone who weighs more than 300lbs to do this test... should be able to find a few volunteers here .

Hahaha, I have the same problem getting trucks to bounce like that too.

IF you're not sure, put some new ones on it anyways, if you can afford to.  

When you take the old ones off...look at what the piston does when you compress it with your hand.  
If it pushes down, but wont come up...they are bad.  If you can push them down and they come right back up...they're fine.  

It'll take some weight to push the piston down...
Grab a block of wood or something and place it overtop of it.  Use your body weight to help push it down.

If they're bad, it'll be obvious once you have them off and do what I just typed above.

I guess I am more concerned about whether the ball joints are bad, as this would be more of a safety issue than just a comfort issue. I took the vehicle to Sears to get the alignment checked, and they said it was already good and they claimed to find no problems with the ball joints, but that they couldn't vouch for the shocks. I'm not sure if they are BSing me, but I would have expected them to suggest new parts if they were needed.

ETA: and yes, I think I am getting pretty severe "cupping". The outside edge of the tires is wearing more quickly, and the wear is not even... almost like someone has filed off a series of flats, making the worn area of the tire feel like a polygon, if this makes sense.