Do Panda subdomain penalties impact main site?

[teokolo]

My main website is about 10 years old, it was hit by penguin (negative seo) in 2013, then partially recovered.
www is the main website (italian), then I have two subdomains (russian and spanish version) which may suffer a Panda penalty because of thin content and poor written pages.

My question is: can subdomains influence main website rankings? Can a subdomain hit by Panda (or Penguin or other penalties) cause some effects to the main website and to other subdomains?

[Rob_Banks]

Keeping in mind that I really do not know the answer, my belief is subdomains probably will not influence the main domain if the main domain is reasonably healthy. There are many sites such as WordPress offering users free subdomains. In many cases, those subdomains will be spam sites or have a lot of spam links pointed at those subdomains.
But, it does not seem to affect the main domain. There is always the argument that WordPress is a pretty strong site, but there are quite a few sites offering the same kind of service which also do not seem to be impacted.

If you were concerned about it, make sure all links from the main domain to any subdomain are "nofollowed". I wouldn't be too concerned about links going from a subdomain to the main domain.

All my opinion, I have no facts to back it up.

[Johan007]

Ask some one with the data like Glenn. Send him a tweet. Failing that get onto a webmaster central hangout with John M.