leyland 154 where to buy parts and how to fix pto speed selector

[bigdaddy9185]

I have a leyland 154 , first problem is where to locate parts in the united states and second problem is on the pto it has a selector lever that has a 1000 rpm , nuteral, and 540 rpm positions. it works in nuetral and 1000 rpm but does not want to stay engaged in the 540 position what is the cause and how to fix , as long as there is aplace to buy nessesary parts.