I need to torque eight nuts to fasten a axle hub to a brake drum, I wonder if is there a multi spindle torque machine to do this simultaneously

thanks for your help

There is! You need fixtured, inline, electric nutrunners. Depending on the size of the wheel, you should be able to get all eight linked together. Certainly, you can get four. In addition, you will be able to program the system to tighten the nuts in a particular sequence, which is critical for wheel assemblies.

There are a couple of companies that can help you out.

Ingersoll-Rand
http://www.irtools.com/tools/fastening/dcelectric/
Spain and Portugual
Tel: +34 91 6277405
Fax: +34 91 6277406

Atlas Copco S.A.E. CMT
José Gárate, 3
Polígono Ind.
28820 Coslada (Madrid)
www.atlascopco.es
+34 91 627 91 00
+34 91 627 92 39
cmt@es.atlascopco.com

Stanley Assembly Technologies can also help, but I don't think they have an office in Spain. They do have offices in France, Germany and Italy, however.
http://www.stanleyassembly.com/contacts/Locations.aspx

Finally, check out the Tightening System 300 from Bosch Rexroth. Bosch has many locations in Spain:
http://www.boschrexroth.com/various/utilities/location/ViewAddrOverview.jsp

Buena suerte! And tell them Assembly magazine sent you!