* Grammer and Ningbo Jifeng plan strategic partnership
* Ningbo to buy 60 mln mandatory convertible bond
* Carmakers welcome Ningbo investment (Adds detail)
FRANKFURT, Feb 14 (Reuters) - Germany's Grammer AG said on Tuesday it plans to sell a 9.2 percent stake to China's Ningbo Jifeng Auto Parts Co Ltd as the automotive interiors maker looks to counter activist shareholders the Hastor family.
Grammer's management has sought to rebuff the Hastors, who own a 20 percent stake in the company and have campaigned for seats on the supervisory board.
Carmakers have grown concerned about attempts by Bosnia's Hastor family to expand their influence over Grammer since a dispute between two other companies controlled by the family and Volkswagen escalated last year, resulting in stoppages of VW's Golf assembly line.
Grammer said Ningbo Jifeng had subscribed to a 60 million euro mandatory convertible bond representing approximately 9.2 percent of Grammer's share capital. This will make it harder for the Hastor family to push through their demands.
Grammer counts Germany's big automakers among its major customers, with Volkswagen alone accounting for 35 percent of sales at its automotive business.
This month, the Hastors demanded that Grammer replace nearly half of its supervisory board.
Grammer's management rejected the request, but the Hastor family demanded an extraordinary shareholder meeting to force a vote.
The family's investment vehicle, Cascade International, Investment GmbH, holds about half the Hastors' stake in Grammer. The other half is owned by Halog, another investment vehicle. Both are controlled by Damir and Kenan Hastor, who are listed by Forbes as the richest Bosnians.
Reuters reported on Monday that Ningbo Jifeng was preparing to buy a 10 percent stake in Grammer at a cost of up to 60 million euros.
$1 = 0.9437 euros Reporting by Alexander Huebner; additional reporting by Arno Schuetze, Edward Taylor and Sangameswaran S; editing by Jason Neely