22-07-2024, 07:13 PM
Hi
The standard Girling arrangement with rollers and an expander wedge pulled by a rod has the actuator housing free to slide sideways (very slightly) to accommodate any mismatch in the shoes. The housing is fixed to the backplate with studs, thackray washers and castellated nuts with split pins. The backplate holes are slightly slotted and the nuts are not done up fully tight.
The Austin version with rotating cams has to have the actuator housing rigidly mounted on the backplate. The same washers and nuts etc are used (presumably because the cost of re-tooling wasn't justified) but the backplate holes are round and the nuts are done up tight.
As far as I can see, the shoes are free to float "up and down" but you could still get the situation where one was being activated slightly before the other. I suspect that in practice once there is some wear in the cam bushes and the more active shoe wears down a bit, everything more or less equalises itself.
The standard Girling arrangement with rollers and an expander wedge pulled by a rod has the actuator housing free to slide sideways (very slightly) to accommodate any mismatch in the shoes. The housing is fixed to the backplate with studs, thackray washers and castellated nuts with split pins. The backplate holes are slightly slotted and the nuts are not done up fully tight.
The Austin version with rotating cams has to have the actuator housing rigidly mounted on the backplate. The same washers and nuts etc are used (presumably because the cost of re-tooling wasn't justified) but the backplate holes are round and the nuts are done up tight.
As far as I can see, the shoes are free to float "up and down" but you could still get the situation where one was being activated slightly before the other. I suspect that in practice once there is some wear in the cam bushes and the more active shoe wears down a bit, everything more or less equalises itself.