The services of a machine shop will usually be need to mount the half shafts in a lathe and machine away the old bearing retaining collar. Access to a press bed of at least 25 ton capacity is required to remove the old bearing and then press into place the new bearing and retaining collar. The highest load will normally be experienced when pressing off the old bearing which tend to come loose with a bang around 16 ton rather than a steady push. Except that after fitting all the parts a final load of 20 tons should be applied.

Due to the high loads that the component parts will experience it is vital that the bearing housing is supported well to avoid damage. It is of no use changing the bearings or even an axle assembly if the bearing housing has been warped during the procedure. Fig 5, Fig 6, Fig 7 and Fig 8 show details of the tool, which I use to hold the housing. This is a very heavy tool because it is used continually. Fig 8 shows the tool on a half shaft with the encircling ring in position this stops the tool sliding off the housing when under load. Normally a tool could be made which would support the housing directly under the threaded bosses of the housing, as long as the situation is monitored.

Removal of the old bearing

After removal of the half shaft from the axle it is necessary to mount the shaft in a lathe and turn down the bearing retaining collar until about 0.010 inch remains when it is easy to split and remove the remaining collar with a chisel, without damage to the shaft surface. It is important that the integrity of the shaft surface at this point is protected because eventually a new retaining collar will have to be pressed on to the shaft and it is only the interference fit between the collar and shaft plus the bearing fit, which retains the road wheel and bearing assembly. An alternative would be to use an angle grinder or cutter and remove the collar without damaging the shaft. Using a lathe does enable the straightness of the shaft to be checked as any out of truth will wear both axle and wheel bearings and take its toll on the half shaft splines.

At this point it is necessary to mount the shaft in a hollow hydraulic press bed and provide a suitable support for the bearing housing whilst the shaft is pressed through, and therefore off the bearing. My own support blocks have been discussed under Tools. It is very important that the flange of the bearing housing, which is about 0.125 inch thick, is not used to support the housing during pressing operations. The bearing housing lower end must take the load and if any load is applied to the flange, distortion and subsequent water entry will result. There is also a very serious possibility of the flange breaking away at some time in the future.

By this time the wise owner will no doubt realise the wisdom of replacing these bearings whilst the car is in his / her own garage or with a specialist of their choice and that bearing renewal is not risking a distress purchase out on the open road.

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