fellow vanagon types

I have seen my share of alternator stud repairs on turned in cores engine
most still had some reminance of the old stud left in place and the bolt or
stud that was used to make the repair was off center and taped in at an
angle. I do all of my stud repairs out of the van and mostly at the time of
a rebuild so this is the perspective of a rebuilder not a mechanic To
properly repair a stud hole thats been drilled out and still has a piece of
stud left you first need to remove the remainder of the broken stud. One way
this is done is to drill the center of the piece stud itself the piece is
usually a crescent shape then it can be folded into itself like closing a
book and removed without making the hole even more egg shaped than it
is.When drilling out a stud  I use a Snap On 1/8 inch double ended drill bit
to make a small centered hole and then work up in drill sizes I've seen
reverse drills spin a broken stud out but don't count on this trick to bail
you out.
Let me back up just a little and explain that the difference between
drilling and taping a hole with side steel form the old stud and one side
aluminum and just taping aluminum is huge. With one side being steel the and
the other  aluminum the hole ends up more to the aluminum side than you
wanted it to be the aluminum is of course softer. I am talking about
repairing the miss drilled out studs for two reasons first this is mostly
what I see a hole with some part of an old stud left in place and a tap job
gone very bad and secondly this is where most stud repairs take turn for the
worst and the incorrect choose is made to send in the tap rather than remove
the rest of the stud and do the helicoil or the time sert repair. I have to
disagree with Dennis on two accounts first it not my experience that the
studs for the alt brackets are any harder than the other 8 MM studs used on
the block and secondly when he says there is no room to use a insert I have
gone up to a 12 mm tap and used what's called a Lyle kit from the days of
the forty horse engines to repair a hole that was supersized before it came
to me. The other consideration for doing a proper repair to a pair of side
by side studs that holds an alt bracket in place is to make sure the bracket
has a flat surface to sit on when it sits against the block. most of the
time the bracket has been loose for some time before the bracket brakes off
a stud and this is plenty of time to make a mess of the aluminum casing some
small filing or grinding of the bracket surface just enough to make it flat
is not going be a problem for the belt alignment but could make the
difference between the bracket staying tight or coming loose in a very short
time. The other trouble I've seen is that its dam hard to get at both nuts
when the bracket is installed and it time to put wrench on the nuts for the
final tug of the wrench. So I don't think this is about helicoils verses
inserts but more about blindly drilling a broken stud out that you cant look
straight at and see the angle your drilling at or the remains of the old
stud  after you have a hole again.
The other thing this repair is about is not drilling threw to the coolant.
Aqua stud repair is never a good time again you can't see the dam hole when
the engine is in their van and its hard to tell when you threw the stud and
into the aluminum. I wont offer any advise on this problem for fear that
someone might get the wrong idea that this is a repair I would consider
doing on one of my rebuilds

going faster miles an hour with radio on
I remain

Bob Donalds
Boston Engine Exchange

http://www.bostonengine.com

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