Smokydiesel Posted June 23, 2009 Share Posted June 23, 2009 Because my engine is making funny grinding noises up front and after having replaced the viscous fan bearing without any improvement, I have now decided to replace the belt tensioner. (300 tdi example shown below, but mine is a TD5 !) But how do I get the thing off ? It is held against the engine block with what looks to be a bolt straight through the middle, but I can't get any socket to slide on the bolt. The bolt looks to be size 14 or 15 but there's not enough room sideways to fit a socket. Or am I missing something here Thanks ! Quote Link to comment Share on other sites More sharing options...
cipx2 Posted June 23, 2009 Share Posted June 23, 2009 I don't know what size the bolt is but is a LH thread. The other bolt fixing the roller to the body is 15 mm so you can make a visual comparison and asses what size socket you need. Use a hexagonal (6 sides) socket, not a bi-hex (12 sides) one. The first are thinner on the outside. Also, if you have an old or amateur socket set they are a bit thicker on the outside. The sockets on a newish professional good quality set are a bit thinner. Quote Link to comment Share on other sites More sharing options...
jbs Posted June 23, 2009 Share Posted June 23, 2009 If you look on Ebay you can find the bearing for about £4.99 i did my girlfriends disco's tensioner bearing after we found it was making a horrible noise there's a circlip on the rear of the bearing and as rightly said it is indeed a left hand thread with a 15 mm head on the bolt HTH John Quote Link to comment Share on other sites More sharing options...
landy andy. Posted June 23, 2009 Share Posted June 23, 2009 It's a multi headed point bolt not a normal one. Andy Quote Link to comment Share on other sites More sharing options...
crwoody Posted June 23, 2009 Share Posted June 23, 2009 As Andy says, the main fixing bolt which holds the tensioner assy to the block is a multi (12) point head. A 14mm 12 point socket fits perfectly, this bolt is a normal RH thread, the other bolt which fixes the tensioner bearing to the arm is a LH thread with a conventional 15mm head. Clive Quote Link to comment Share on other sites More sharing options...
cipx2 Posted June 23, 2009 Share Posted June 23, 2009 Oops .... That's correct, the bolt is 12 point headed. It's the other way round I previously wrote. 1 Quote Link to comment Share on other sites More sharing options...
calle-fas Posted June 23, 2009 Share Posted June 23, 2009 If you buy a cheap 14mm 12 point socket and grind it down a little it will do the job. At least on my car the bolt was easy to loosen so no great power is needed. Quote Link to comment Share on other sites More sharing options...
crwoody Posted June 23, 2009 Share Posted June 23, 2009 ... a cheap 14mm 12 point socket and grind it down a little ..... I found a standard one works fine for me, but a thick walled socket may not fit into the recess. Quote Link to comment Share on other sites More sharing options...
M&S Posted January 29, 2010 Share Posted January 29, 2010 Having just done this on the TD5 Discovery today I found a 1/4" drive, 14mm, 12 point socket fits perfectly. I was struggling (you can't see it in situ on the Disco) so did a quick search before starting and found this thread. I have a 1/2" drive but that wouldn't fit (depsite the thin, tapered wall). Hope this helps someone maybe needing to buy a socket for the job Turns out the chirping wasn't the tensioner, or the idler, it was the new Britpart belt. Put the old LR belt back on and all is well Quote Link to comment Share on other sites More sharing options...
JC_DJ Posted June 7, 2017 Share Posted June 7, 2017 Hi Guys, I've just joined the forum on the back of this thread as I found it very useful... So thanks to all the guys on here, especially cipx2 for the picture. Using the information you provided it took me only 20 minutes to replace the tensioner & belt... bobbling tensioner and associated squeak problem solved. Thanks again! 1 Quote Link to comment Share on other sites More sharing options...
paulw60 Posted January 6, 2020 Share Posted January 6, 2020 Thanks guys, this thread is a great help. Probably got a 12 point socket but at 3 quid I bought another off ebay just to make sure Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.