Monday, 30 July 2012

Donor Rebuild Part 3

Chassis collection is now less than a week away, so I have been concentrating on the donor component rebuild in preparation. The lower rear wishbone has two pairs of needle roller bearings for the inner pivot and these are a light press-fit into the respective bores. The gap between each pair is to allow for a grease fitting on the outside to be used during servicing and a sleeve is used to provide the running surface.

The final job on the rear uprights is the installation of the wheel bearings. As per other parts of the original car, the bearing clearance is controlled with spacers. In this case, the bearing has to be pressed into place with a known thickness spacer and the clearance measured. The target clearance can then be achieved by selecting a slightly thinner spacer of the correct thickness. The final bearing clearance is achieved by installing the driveshaft through the middle with the correct spacer in place and fully tightening the hub nut. Before this can be carried out though, the inner seal needs to be pressed in place.

Monday, 16 July 2012

Donor Rebuild Part 2 - pivots

The big new is that I finally have a completion date of the chassis which will be ready by the end of this month. The donor brakes and differential are back from reconditioning and I am progressing the rebuild of the suspension components. To this end, I have been working on the lower front wishbones and fitted the replacement bushes

In addition, I have assembled the lower pivots on the rear uprights. This is a particularly involved process as there are two taper roller bearings which must be shimmed to achieve the required endfloat. This involves a dry build with a known thickness of shim pack in place and then the float of the bearings measured. Shims can then be removed to achieve the required clearance on the bearings. It then has to be dismantled to allow final assembly with the bearings packed with grease and the outer seals to be fitted. These are very ‘old school’ where a ring of felt material is used – this has to be soaked in engine oil for at least 24 hours to ‘load’ it with lubrication before a very messy installation. Still, this is now completed and it is all held together with a temporary retainer because the lower pivot shaft does the job in the final assembly, but this can only be fitted on the car.

One last job remains on the rear uprights with setting the bearing clearances for the output flange. This has required a specific bit of tooling to be manufactured, but fortunately, I have access to a lathe to allow this. There is still some assembly, checking and shimming required on the differential which centres the brake discs in the callipers and sets the rear suspension geometry (camber and toe) however, this is more easily carried out as the parts are assembled to the chassis. Bring on the end of the month!