Checking balljoints


#1

HOW DO CHECK BALL JOINTS ON A 1994 GMC JIMMY S15,. SHOP TOLD ME I NEED ALL 4 JOINTS ON A FREE INSPECTION I CHECKED FOR MOVEMENT IN THE FRONT END BUT FIND VERY LITTLE TRUCK DRIVES FINE NO WEAR ON TIRES I THINK JUST TRYING TO GET AN EXTRA SALE THANKS


#2

The upper ball joint should have ZERO movement, if there is any radial movement(in and out) they need to be replaced.

The lower ball joints can be checked for movement but there is a spec for allowable movement. The shop that told you they were bad should have told you how much axial and radial movement there was and what the spec was.

The lower ball joint could also be a wear indicator style of ball joint. If the shoulder of the grease fitting is flush or sucked into the ball joint it is worn out and needs to be replaced.

Did the shop give you any of this information?

By law I have to include the specs and actual dial indicator readings of the ball joints on my repair orders.

You should find out if your state requires repair shops to include this information on the customers repair orders.


#3

There are several ways to check them. On GM, there is the shoulder to check, or used to be anyway.

One of my favorite ways of checking the whole front end is to have someone move the steering wheel back and forth, 1/4th turn every second or so. Lay on the ground in front of the vehicle and watch each part. You will see anything that needs to be replaced.

You can also jack up the vehicle until the tire just clears the ground, then stick a shovel under the tire and move the tire up and down while watching the ball joint.

You can also take off the tire, squeeze the ball joint top to bottom with a large pair of Channel lock pliers. Measure the uncompressed and compressed height with a pair of calipers and check the difference against the service manual.


#4

On your vehicle, the upper ball joints are “unloaded” and you can check them by simply trying to move the top of the tire in and out. To “unload” the lower joint, lift the wheel off the ground by jacking up the lower control arm or “A” frame. Now BOTH joints are unloaded and any slop will be easy to detect.

The suspension spring or torsion bar “loads” one of the joints and makes checking it impossible unless this spring pressure is removed first…By supporting the lower control arm with a jack, the pressure is removed from the ball joint…