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AndrewMac85

Serpentine Tensioner pulley bolt stripped

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hey guys,

 

I decided to change the whole tensioner assembly as it looked pretty knackered. I read that I should use a torx 50, with a breaker bar, lefty loosy. This thing is hard on, and my attempts to take it off have damaged the thread of the bolt.

 

Do you think I should:

 

1. Attempt to hammer in a larger 55 bolt and keep at it.

2. Attempt to cut apart the pulley to expose the bolt.

3. Attempt to pad the inside of the bolt for resistance?

 

I'm worried about causing too much damage as this goes into the chain cover, and I really wont want to have to replace that. What do you guys think?

 

 

Andy

84263b26-84f0-42a5-84be-dc76fac5205d.jpg

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you've damaged the head, not the thread.

 

I would try a T55 in it, difficult to tell with the angle of it, but a Nut-grip may work if it has a square socket head.

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What about using a dremmel or angle grinder to cut a slot into it and see if you can get a flat headed bit or screw driver into it?

 

Not a lot of room I know, just another idea

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never found that approach to work ever, not enough purchase, smashing it round with a chisel in the groove you've cut can work though.

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 If you've got the room, grind the head off the bolt, pop the tensioner off and then the rest of it will probably wind out by hand as there is no longer any resistance on it. If not, get a set of grips on it....

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On 06/10/2017 at 11:57 AM, welshpug said:

smashing it round with a chisel in the groove you've cut can work though.

 

+ 1 even without grinding a slot in it, knocking it round with a punch or drift can break it loose. I'd go in where the writing is with a sharp nosed punch, once you've got a nice indent start canting the punch over and driving the bolt round. The torque/shock should hopefully break it loose.

 

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Sorry to ressurect a zombie post. But I've come back round to this after leaving as it was.

 

I've tried punching in a larger bit, which gave it some turning force. However the breaker bar eventually just tore up the thread more. I did try alternating between tightening and loosening to help.

 

I'm now using a cold chisel and a hammer to try and budge it, no dice so far. Just to be sure this isn't reverse thread is it?

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I was thinking that the tensioner pulley assembly is held by two bolts which you expose when you press the tensioner down.

 

I assume you can remove the whole tensioning mechanism without faffing with removing just  the tensioner pulley. Once removed the whole thing then you may be able to remove the bolt and replace the pulley.

 

https://www.pelicanparts.com/BMW/techarticles/BMW-5-Series-E39/106-ENGINE-Tensioners_And_Pulleys_Removal/106-ENGINE-Tensioners_And_Pulleys_Removal.htm

 

 

Edited by amazighman

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2 hours ago, AndrewMac85 said:

 

I'm now using a cold chisel and a hammer to try and budge it, no dice so far. Just to be sure this isn't reverse thread is it?

If you cant detention the belt anymore you can cut it off , be careful  while doing it

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Fixed! Just closing this up for anyone who stumbles onto this thread. After attempting heat / hammering in a larger bit / JB Welding a bit in / Cold chisel on the bolt .. I finally gave up and cut the pulley off. It was a truly horrible job, hours of dremel work to cut through the bearings and the bolt to free it. Eventually after removing most of the pulley and using a chisel I was able to turn it a few turns and back it off.

 

Here is the aftermath..

 

 

bolt.png

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