By 1983, most Coach Manufacturers  had converted to 
the new full integral power steering system similar to the one you have in your car .
The old truck power assisted steering system is very out dated now.
 
"Some consider it dangerous if  maintenance has not been kept up to date  ..."

This is where we updated an older coach to the new Ross system 

Converting old slave cylinder power-assist steering 
into the new full integral steering...