17-09-2023, 11:21 PM
Simple things to diagnose worn CV's (which can cause a knocking noise)
Jack the van up and give the wheel a spin. If badly worn, you will here/feel the knocking when turning.
While jacked up (use a fixed stand in addition to jack for safety), grab the axle. It should be free to push left/right (towards/away from the wheel) freely and smoothly.
If you hold the wheel, there should be no movement turning the axle (forwards/back). Checking this on the gear box side is a bit harder as even if it's in gear, the output shaft is not fixed. You can hold the outer of the CV and try for movement (rotating)
While hte wheel is in the air, grab the top and bottom of hte wheel and try to rock the wheel (push the top towards the van, the bottom away) and alternate to feel for movement in the bearings. Also spin the wheel, it should turn soothly with no vibration.
This will not always pick up issues. While driving, the best way to check CV's is in a corner when there is more articulation in the axle. Go around a corner fast enough for the van to lean a bit (doesn't need to be excessive) and accelerate lightly. You need to try this turn left and right. The inside wheel/CV's will knock if you have wear (pitting) in your CV's.
If it's wheel bearings, it's more a vibration rather than knocking and it will be the on the outside wheel.
So it's good to have a helper who can listen closer to the wheel you are testing.
Jack the van up and give the wheel a spin. If badly worn, you will here/feel the knocking when turning.
While jacked up (use a fixed stand in addition to jack for safety), grab the axle. It should be free to push left/right (towards/away from the wheel) freely and smoothly.
If you hold the wheel, there should be no movement turning the axle (forwards/back). Checking this on the gear box side is a bit harder as even if it's in gear, the output shaft is not fixed. You can hold the outer of the CV and try for movement (rotating)
While hte wheel is in the air, grab the top and bottom of hte wheel and try to rock the wheel (push the top towards the van, the bottom away) and alternate to feel for movement in the bearings. Also spin the wheel, it should turn soothly with no vibration.
This will not always pick up issues. While driving, the best way to check CV's is in a corner when there is more articulation in the axle. Go around a corner fast enough for the van to lean a bit (doesn't need to be excessive) and accelerate lightly. You need to try this turn left and right. The inside wheel/CV's will knock if you have wear (pitting) in your CV's.
If it's wheel bearings, it's more a vibration rather than knocking and it will be the on the outside wheel.
So it's good to have a helper who can listen closer to the wheel you are testing.