Hi Diablo,

The Scott Bonnar Model 590 was first introduced in 1976 and was manufactured in the Thebarton factory in South Australia. Both the Model 430 and 590 were a radical design departure from the cylinder mowers that were popular at the time...eg. the Model 45. wink
In some quarters, they are considered an abject failure, and most spare parts are now like hens teeth, some almost impossible to come by. cry

If you could post the model, type and code numbers stamped into the metal air cowling of the Briggs engine, we can give you an approximate age of your machine.
The numbers are in the location usually near the intake manifold...please post the whole string of numbers. wink
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There is a good thread here on the Model 590 drive problems that may prove of interest to you....Click HERE

If you are chasing a metal crown drive wheel for this machine, I will send you a PM with the details, just look for a flashing envelope in the toolbar above next to 'My Stuff'.
Hoping this is of help,
cheers

Please do not PM me asking for support. Please post your questions in the appropriate forums, as the replies it may receive may help all members, not just the individual member.
Kindest Regards, Darryl grin