Fault diagnostics

[Dave Adams]

When diagnosing some faults some mechanics have well tried methods that for the most part work very well.

take wheel bearings....recently my truck had a wheel bearing failure, i noticed it while driving and noticed that when turning left the bearing noise went quiet and when turning right it got noisier......therefore the N/S (front axle in this case) bearing was suspect, and on checking it it was warm to the touch...sorted.

And so it was on my sierra just recently, both bearings were replaced a few thousand miles ago but i started to get a noisy bearing (as above, N/S/F again) it was replaced and the noise for the most part disappeared, but there was still a noisy bearing (slight) the noise quickly developed and the fault diagnosing indicated N/S/F  again.....

I could not see it being the new bearing so i did the O/S one... and noise gone! weird.....

[Dave Adams]

The bearings i have fitted recently were sealed to the outer side but not fully sealed to the inner edge.

[Dave Adams]

Oil from the diff

[Paul Sheridan]

Talking of wheel bearings,  what lubricates the wheel bearings on an English axle, are they greased or should there be enough oil in the diff to travel along the axle tubes to lube the bearings?