Green’s Dictionary of Slang

a broken-down old vehicle.

1906		Bulletin (Sydney) 3 May 14/2: Waiting [...] for the ramshackle shanghai at Port Pooncarie.
1912		Bulletin (Sydney) 10 Oct. 48/2: As we got off the ramshackle bone-bruising shanghai at Jumping Sandhills the burly publican came out of the bar. / ‘Any of yous bloques for dinner?’ he asked. / ‘Yes,’ said I, ‘we two and the driver.’ [Ibid.] 21 Nov. 16/4: When you have sampled many ways and means of getting elsewhere in the great spaces of the interior, including rides on donkey-back and camel-back, in shanghais, sulkies and waggonettes [...] you can appreciate a railway car much more than when you come off a sea voyage, or have been used to motoring on civilised roads.