Q: How to check and replace ball joints in Chevrolet Avalanche,Silverado,Suburban,Tahoe,GMC Sierra,Yukon,Yukon Denali and Yukon XL's suspension system?
A: To test the upper ball joint, detach it from the Steering Knuckle and check for looseness or use a dial indicator to measure deflection. The upper arm should be replaced if the reading is above 0.079 inches. Examine the lower ball joint for any looseness, or use a dial indicator to measure its deflection. Replace the ball joint if your measurement exceeds 0.079 inches. Demounting of lower ball joint requires Control Arm removal and knocking back crimped areas with a hammer and chisel. To attach it, shove the new ball joint into position within control arm and stake or crimp it down tightly. The whole upper control usually goes with an upper ball joints hence should be replaced as such because they are inseparable from one another by design. Check front-end alignment and adjust accordingly as required.