[s-cars] Crank Bolt From Hell (lessons learned)

[Fred Munro]

Hi Russ;

The OEM crank pulley bolt on my '91 200q had dry threads and locking
compound under the bolt head. The OEM bolt on my '94 S4 had lube on the
threads and no locking compound. The first time I did the t-belt on the S4 I
used Loctite blue on the threads and under the bolt head. I had no problem
taking that bolt out the second time I did the t-belt, but this time I lubed
the threads and used Loctite blue under the bolt head. I thought the Loctite
on the threads might transfer some torque to the crank while loosening the
bolt. I figure the torque on the bolt is what keeps it tight and the Loctite
under the bolt head is added insurance to secure it to the pulley and keep
water out to minimize corrosion.

Paul, I've cc'd you as this answers your question as well. I suspect some
shops wouldn't torque this bolt enough if they are not used to working on
these cars - maybe that's what happened to your Avant. Many engines only
take 100 - 150 ft-lb or so on the crank bolt.

Fred Munro
'94 S4

-----Original Message-----
From: Southerlin, Russell S [mailto:russell.s.southerlin at lmco.com]
Sent: January 4, 2005 10:46 AM
To: Fred Munro; Tom Mullane
Cc: s-car-list at audifans.com
Subject: RE: [s-cars] Crank Bolt From Hell (lessons learned)


I forgot to mention this part.

No, the threads did not show any obvious signs of locking compound but
there
was kind of a shiny sheen to the thread surface - not sure if this was
lube
or not.

I suspect this may have been the factory installation i.e original
timing belt.
The bolt head had no signs of wear from being previously removed.

There was no sign of locking compound under the head of the bolt?

What is recommended for locking compound? I have Permatex blue which is
the
non-permanent type.  I am planning on using it sparingly on the threads
only
and try to not get any on the head of the bolt.

Russ

-----Original Message-----
From: Fred Munro [mailto:munrof at sympatico.ca]
Sent: Monday, January 03, 2005 07:41 PM
To: Southerlin, Russell S; Tom Mullane
Cc: s-car-list at audifans.com
Subject: RE: [s-cars] Crank Bolt From Hell (lessons learned)


Hi Russ;

When you removed the bolt, did the threads have lubricant on them? Were
there signs of locking compound under the bolt head or on the threads?

I use a 3/4" drive socket and breaker bar with a 6 foot pipe extension
for
this job.

Fred Munro
'94 S4


-----Original Message-----
From: s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com]On Behalf Of Southerlin, Russell
S
Sent: January 2, 2005 8:19 PM
To: Tom Mullane
Cc: s-car-list at audifans.com
Subject: RE: [s-cars] Crank Bolt From Hell (lessons learned)


Tom,
The tranny was in neutral so any stress transmitted through the clutch
would be from the mass of the tranny gears, clutch and such.  It dis not
appear that much of the "torque" was getting transmitted through the
tranny as I could hold the harmonic balancer from rotating relatively
easy by hand.  I can see where the impact hammering could potentially
affect rod bearings and such.

I was wondering myself if the gun may have cracked the key.  The impact
only puts torque into the head of the bolt and very little into the key
IMO, where the conventional tool is reacting the torque through the
harmonic balancer and potentially into the keyway.  I believe the forces
on the keyway are much greater with the tools vs. the impact.  Maybe the
impact has other negative side affects but I still think a sheared key
is less likely with the impact.

Maybe the thing to do would be to try the conventional tool up to about
600ft-lbs and if it does not budge then do the impact.

Russ


-----Original Message-----
From: Tom Mullane [mailto:tmullane at snet.net]
Sent: Sunday, January 02, 2005 5:52 PM
To: Southerlin, Russell S
Cc: s-car-list at audifans.com
Subject: RE: [s-cars] Crank Bolt From Hell (lessons learned)


Date: Sun, 02 Jan 2005 17:20:09 -0700
From: "Southerlin, Russell S" <russell.s.southerlin at lmco.com>
Subject: [s-cars] Crank Bolt From Hell (lessons learned)
To: s-car-list at audifans.com
Message-ID:
	<3352E03FC741BB4E97EDB6991C8DC44105CB1A83 at emss02m18.us.lmco.com>
Content-Type: text/plain; charset=iso-8859-1


Russ,

Sounds like a fun time.

I disagree with you about the impact gun.  The gun is tough on the
clutch,
trans, and possibly the rod bearings.  Sometimes ya gotta do what ya
gotta
do to get things apart, but the impact is a last resort for me.  I
wonder if
the key was cracked by the impact gun?  I've seen them damaged, but
usually
when the bolt is too loose - obviously not an issue in your case ;-)

Tom


<snip>
Now for the lessons learned.  I believe the safest way to remove the
crank
bolt is the impact wrench.  I believe if I had continued to apply more
torque to the bolt with a bigger breaker bar it would have sheared off
the
keyway and possibly spun the crank - not a good day no matter how you
look
at it.  Next time I will acquire a 3/4 inch impact by renting or
borrowing.
The impact only applies the force right at the bolt head and it is not
reacted through the harmonic balancer and keyway.  The proper tool
(3056?
tool) or my home made tool reacts the torque through the harmonic
balancer
and keyway which is not designed to take 800ft-lbs.

<snip>

Russ
95.5 S6
Castle Rock, CO

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