02-03-2022, 10:25 AM
Hi Bellini
If I understand it correctly, you are fitting an Austin cross shaft and Austin brakes to a later chassis that originally had Semi-Girling brakes. The Semi-Girling setup was introduced in mid 1936 with the ARR Ruby, and differs in several ways including the cross shaft and its bearings.
Fortunately, the chassis holes for the centre bearing bolts and outer bearing rivets stayed the same. I think your best bet would be to source some of the earlier spherical bearings/brackets and refurbish them. All three are different. The bearing bracket rivets can be drilled out and replaced with 1/4 inch BSF high tensile bolts and nyloc nuts. The centre bearing is a bolt-in affair, with slot holes in both the plate and the chassis so that fore-aft and up-down alignment can be achieved before tightening.
You are probably aware that the spherical inserts should be held quite firmly between the bevelled plates,with just enough movement to allow the shaft to align. The shaft rotates within thin zinc "top hat" liners. You don't want too much bearing play at the offside (driver's) end, or it will spoil the balance of forces between the rear brakes and the offside rear will be too enthusiastic.
An alternative would be to make custom bearings to adapt an Austin cross shaft to the semi-girling bearing brackets. Some people have used Delrin or similar for this .
In the recent past I have fully refurbished and fitted a semi-girling cross shaft. It's not a job for the faint hearted, and I spent a long time drawing up the various bits in order to work out where it all went. An unbelievable number of felt rings and washers ! My conclusion is that sourcing and refurbishing a semi-girling shaft to fit your chassis would be a much bigger job than sourcing the earlier Austin bearings/brackets or making custom bearings.
If I understand it correctly, you are fitting an Austin cross shaft and Austin brakes to a later chassis that originally had Semi-Girling brakes. The Semi-Girling setup was introduced in mid 1936 with the ARR Ruby, and differs in several ways including the cross shaft and its bearings.
Fortunately, the chassis holes for the centre bearing bolts and outer bearing rivets stayed the same. I think your best bet would be to source some of the earlier spherical bearings/brackets and refurbish them. All three are different. The bearing bracket rivets can be drilled out and replaced with 1/4 inch BSF high tensile bolts and nyloc nuts. The centre bearing is a bolt-in affair, with slot holes in both the plate and the chassis so that fore-aft and up-down alignment can be achieved before tightening.
You are probably aware that the spherical inserts should be held quite firmly between the bevelled plates,with just enough movement to allow the shaft to align. The shaft rotates within thin zinc "top hat" liners. You don't want too much bearing play at the offside (driver's) end, or it will spoil the balance of forces between the rear brakes and the offside rear will be too enthusiastic.
An alternative would be to make custom bearings to adapt an Austin cross shaft to the semi-girling bearing brackets. Some people have used Delrin or similar for this .
In the recent past I have fully refurbished and fitted a semi-girling cross shaft. It's not a job for the faint hearted, and I spent a long time drawing up the various bits in order to work out where it all went. An unbelievable number of felt rings and washers ! My conclusion is that sourcing and refurbishing a semi-girling shaft to fit your chassis would be a much bigger job than sourcing the earlier Austin bearings/brackets or making custom bearings.