graham.hassall
Well-known member
- Joined
- 29 May 2009
- Messages
- 182
Hi All
Last night after I accelerated hard a strange screeching sound started at the rear of the car. I stopped and the engine seemed fine and gears were OK so I returned home (1mile away) thinking the alternator was giving up. On closer inspection I discovered that the lower idler pulley was loose. Very loose in fact as the M8 screw holding it to the block had sheared off at the block and the belt was holding the pulley in position. The remnants of the bolt and coverplate (washer) had disappeared.
Gloom and doom how do I get the remnants of the stud out, as it was flush with the block apart from a small burr. Well as luck would have it by placing my finger on it and discovering I could turn it and unscrew it!
Well this could be the end of the saga. I will buy a new M8 x 55mm screw (does anybody know the pitch) and washer probably from Porsche. I may buy a new pulley as well as there is some marking on the pulley wheel. I have looked up in the manual section 13 77 20 and see that the tightening torque is only 17ftlb. This seems very low. Should I be using some threadlock as well?
The only thing that now concerns me is why did it happen? The pulley rotates nice and smoothly. Could the screw have started to loosen through vibration and created an eccentric load which then sheared of the screw?
Is this common my car has covered 117k?
Thanks in advance for any feedback.
Graham
Last night after I accelerated hard a strange screeching sound started at the rear of the car. I stopped and the engine seemed fine and gears were OK so I returned home (1mile away) thinking the alternator was giving up. On closer inspection I discovered that the lower idler pulley was loose. Very loose in fact as the M8 screw holding it to the block had sheared off at the block and the belt was holding the pulley in position. The remnants of the bolt and coverplate (washer) had disappeared.
Gloom and doom how do I get the remnants of the stud out, as it was flush with the block apart from a small burr. Well as luck would have it by placing my finger on it and discovering I could turn it and unscrew it!
Well this could be the end of the saga. I will buy a new M8 x 55mm screw (does anybody know the pitch) and washer probably from Porsche. I may buy a new pulley as well as there is some marking on the pulley wheel. I have looked up in the manual section 13 77 20 and see that the tightening torque is only 17ftlb. This seems very low. Should I be using some threadlock as well?
The only thing that now concerns me is why did it happen? The pulley rotates nice and smoothly. Could the screw have started to loosen through vibration and created an eccentric load which then sheared of the screw?
Is this common my car has covered 117k?
Thanks in advance for any feedback.
Graham