2400 miles driven and one of the two rear axle wheel bearings has failed on a sub 2500lb car. Sad shape of affairs this is indeed.
Fist off, the wheel bearing in question has the SKF name all over it; made in of all places, China. I have a problem with offshoring and a bigger problem when the offshored goods are defective. QA was definitely not in the picture when this bearing was made. And no, this is not the first one to fail. My cousin Jim Thompson’s TR4 had the exact same thing happen on an identical rear axle as used on bowtie6.
So what is all this fuss about? Let me show you. After lifting the rear of my TR6 up in the air, we were able to determine the driver’s side axle bearing was at fault. I took the caliper off, then the rotor and the retainer plate off the rear housing. A couple of strikes with a deadblow hammer and the axle was out. This is what it looks like:
The picture above shows the bearing and on top of it the retaining ring. In order to minimize damage to the axle, the bearing is cut as follows:
And once the outside race “pops” (it is under tension and cutting the outside race eventually makes a muffled “pop”), we get a chance to see inside. This is where things get very interesting:
In the picture above we have the outside race cut showing the ball bearing retainer. It is what lies below the ball bearings what is of interest!
Here we start to see the root cause of the problem. The inside race should be slick, polished and accurately ground. Look at the photo above: the lower half is indeed properly hardened and finished. However, see the top half? It looks very rough indeed. That is where the racket was coming from. Another couple of pictures:
Further inspection revealed the outside race was in good shape. No case-hardening issues there. However, the inner race was very poorly made – somehow the case-hardening process was not properly applied and the surface of the inside race pitted severely after only 2400 miles. This cannot be blamed on poor lubrication because these are sealed bearings.
A new bearing has been sourced – unfortunately it is SKF. I just hope I’m not here in another 2500 miles talking about another bad apple. Here is a photo of the new bearing being pressed in:
Once I got the axle back in the housing and bolted it all back together we were set to go. I put about 50 miles this afternoon and all is good. I just keep my fingers crossed the new bearing lasts a little longer.