View Full Version : Bottom alternator bolt sheering - 300 tdi
86mud
25th January 2013, 07:28 PM
Hi all
 
well....it always happens...4pm on a Friday afternoon in humping down rain...all of a sudden I get a bad fan belt squeek noise coming from my 300Tdi.  
 
I pull the belt off to discover the alternator is flapping in the breeze with only the top bolt holding it on!
 
Of course the shank of the bolt is stuck in the threaded part of the alumnium housing.
 
I will try a screw extractor but getting in there is a problem.  Will have to pull the intercooler to give me some room for the drill.
 
Question.  Am I able to drill this out and use a bolt right through with a nut on the back like the top bolt?
 
Not happy...I replaced everything on front of the motor only 15.000km ago, about 18 months!
justinc
25th January 2013, 07:31 PM
Hi Andrew.
The last one I did just came out using my finger. USUALLY they break due to being loose, and the vibration just snaps the head away. This means the threaded section is just sitting there awaiting removal.
Good luck mate.
JC
tonic
25th January 2013, 07:53 PM
If you dont want to take out cooler, try a 90' bend unit for the drill. In answer to your other question. If you have to drill that much, I would re-tap the hole. Bolt should come out. We sheer bolts on the drilling rigs all the time, they normally come out. Try using a pointed hole punch and see if it will turn using the punch and hammer, I do this at work all the time.
 
Have fun.
86mud
26th January 2013, 03:32 PM
Thanks guys...
 
the problem is the bolt sheered inside the housing so no way of using fingers.  Drilling is the only answer
 
What really disappoints me is the aluminium bracket where the alternator mounts to was brand new not evern two years ago....and because the bottom bolt sheered, the top bolt has been allowed to move and it has chewed the hole out a bit.
 
At $600 (2 years ago)....that bracket was expensive!!  Looks like I will have to remove it entirely from the front of motor (means water pump and P gaskets...) and hopefully I can get someone to weld up the slack in the hole.
 
Not happy
tonic
26th January 2013, 03:35 PM
bugger:(
86mud
8th February 2013, 11:48 AM
Well..the news just gets worse...
 
Pulled the radiator and intercooler out so that I could extract the broken bolt from the lower alternator mount on the aluminium bracket. 
 
Now what do I find?  The bottom mount on the actual alternator is cracked!!! NOT HAPPY!  I replaced all this only 18 months ago.  The alternator was the 100amp heavy duty unit so i am up for another one of those, plus the water pump has a hairline crack at the bottom bolt as well!.
 
Far out.  how does all this damage occur with brand new parts?
 
Really not happy right now.
Blknight.aus
8th February 2013, 01:13 PM
WE might be able to recase the alternator.
I have a spare unit Im going to strip down for rebuild if the guts cross load something can be arranged.
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