I need to replace the front auxiliary idler on my 2.4 JTD 156 10v, 2001 vintage, but it seems to be digging its heels in. It loosens easily but the whole thing turns with the bolt head and after 1/2 a turn it gets tight to point where the bolt feels it will snap.I assume the eccentric adjustment has seized, will this stop the bolt coming out with the adjuster on it? If I can stop the tensioner body turning will it make a difference? When putting the new one on, how do I set the eccentric adjustment? I understand I have to lower the engine to withdraw the bolt fully. Thanks for any advice or experiences!