The bolts are 8mm x 1.0 x 25mm  N 010 102 3     $2.45 ea dealer list
The nuts are 8mm x 1.0 self locking  N 022 152 1        $0.67 ea dealer list

Rennie
Peyton Cramer VW

sxs@concentric.net wrote:
>
> At steps 7-9 it might be noted that it is a little
> tricky removing the casing to get to the VC.  It can
> hang up on the Diff. mount bar, the one in a "U" shape,
> and I had to remove that bar to get it off and out of
> the way.
>
> Any one have the part numbers handy for the drive shaft
> nuts that must be replaced?
>
> I will be upgrading the syncro.org site soon and will
> restore the photos for the VC change.  The site where i
> had the photos stored went under.  Peter dug them up
> for me and I can send them out till the site is fixed
> again.   Maybe I can use this description on the site?
>
> Steve
>
> Derek Drew wrote:
> >
> > OK Brian. You are one of many people asking me for a
> > definitive guide to replacing your VC. So for the
> > benefit of the archives, here goes the best most
> > current version of these instructions. No special
> > tools or automotive experience are needed for this
> > job, and because it is so simple, it should not be
> > farmed out to a transmission shop. The best thing I
> > could say, going from memory, is to....
> >
> > 1. Drive van up on 4 ramps
> > 2. Put jackstands under van in case ramps fail
> > 3. Record and mark the alignment of the driveshaft to
> > the front differential so that you can put the same
> > bolt through the same holes of each unit upon
> > reassembly. This will reduce the chances of your
> > ending up with an out of balance driveshaft on
> > reassembly.
> > 3. Unbolt the four forward bolts holding the
> > driveshaft on with either a 1/2 inch or 13mm open end
> > wrench and some liquid wrench. If the 13mm wrench
> > doesn't work that great, try the 1/2 inch open end
> > wrench.
> > 4. Loosen the bolts holding the front differential so
> > that differential may be shifted around.
> > 5. Shift the front diff forward so that the
> > driveshaft will fall away from the front diff. Shift
> > that driveshaft out of the way.
> > 6. Remove the oil from the front diff through the oil
> > drain hole. Throw that oil away by bringing it to
> > your nearest auto repair shop for disposal.
> > 7. Remove the 13ish? 13?mm bolts holding the back
> > half of the front differential onto the vehicle and
> > then pop the rear third of the differential off
> > backwards. Do not looosen the big bolt at the
> > rearmost point in the front differential
> > 8. Have something on the ground to catch the residual
> > oil that will spill out.
> > 9. Pull the VC out and replace, being careful to
> > reinstall the little metal washer that is wedged in
> > there. No special tools or measurements of any kind
> > are needed.
> > 10. Bolt everything back together, but bolt the front
> > differential down last after shifting it around to
> > properly seat it in relation to the rear
> > transmission. When bolting the driveshaft back on,
> > either replace the 4 driveshaft nuts with factory new
> > ones the way VW says to do it (proper way), or just
> > use Red Loctite the way about half the people on the
> > list do it (universal list method) or reuse the
> > original nuts with no loctitie the way the other half
> > does it (pogo stick method; see below).
> > 11. Refill the front differential with GL-5
> > Transmission oil using the factory specified
> > viscocity. Mobil 1 makes a good GL-5 for the front
> > diff. (Make sure not to use GL-5 in the rear
> > transmission, however, as that takes only
> > GL-4--eveybody wisely uses Redline GL-4 synthetic for
> > the rear.)
> > 12. The entire job should take you about 1 hour. But
> > for some reason --I cannot predict in advance why --
> > it will actually take you 5 hours :-). Some members
> > have reported broken bolts holding the diff in place,
> > or broken rubber mounts, so be prepared to hunt these
> > parts down if you decide you need to replace them.
> > 13. Some people decide to remove the diff entirely to
> > do this job. You can do that, but that means you have
> > to disconnect the front CV joints, which is a pain.
> > Still, those front CV joints probably need their
> > grease to be renewed anyway. And as long as you are
> > regreasing the inner front cv  joints, you might as
> > well do the outers too, and inspect the boots, and
> > then why not the rears and HEY lets not loose focus
> > here...
> > 14. The best description on how to change your VC was
> > originally posted to the list by Rainer about three
> > years ago, but Steve Schwenks photo essay matched
> > this post in utility and interest. Too bad it is not
> > on syncro.org right now.  I will copy Ranier's post
> > below.
> > ABOUT THE POGO STICK METHOD.
> > This is actually a method of easily removing the
> > transmission and engine from the vehicle.
> > Essentially, the procedure is to skip using loctite
> > on the nuts that hold the driveshaft on the front
> > diff, and don't replace those nuts with new nuts
> > either. Just reuse your old nuts even though the
> > factory says to replace them. When the nuts or bolts
> > eventually fail, the driveshaft will drop down on the
> > highway and get lodged on a rock, crack, or other
> > obstacle and remove your trannsmission and engine in
> > about two seconds. This also works in the event of a
> > front U-joint failure. If this does not appeal to
> > you, install a strap that holds up the front
> > driveshaft in the event its front attachment point
> > fails. I haven't put my strap in yet myself, but I
> > think about it from time to time.
> >
> > >> There is an excellent article by Steve on how to
> > >> replace the VC at www.syncro.org in the Tech
> > >> section called "Replacing the VC (photos):
> > >
> >
> > Reproduced below is Rainer's version of the above. It
> > differs from my version in some important respects so
> > it pays to read both posts. Note that Rainer is one
> > of the world's leading observers of the Syncro
> > Viscous Coupling, and is of much higher intellect
> > than the average Vanagon or Syncro poster so we are
> > lucky to have him among us.
> >
> > > VW's original (German) repair manual doesn't say
> > > much  about how to test
> > > the viscous coupling.  They only recommend placing
> > > the  rear wheels in a
> > > break testing stand.  If you then switch to  the
> > > G-gear (creeping gear),
> > > the front  wheels should move the van  out of the
> > > test stand as soon as
> > > the engine is revving slightly above idle.   If the
> > > front wheels fail to
> > > do so the viscous coupling is to be replaced, VW
> > > says.  VW adds another
> > > tiny sentence  to this, saying that only  when the
> > > engine  is revving at
> > > idle and with the G-gear  switched in, the viscous
> > > coupling is able  to
> > > absorb all the torque to the front wheels and keep
> > > them from moving.
> > >
> > > To me  this   last and  rather   ill-formulated (in
> > > the  German  manual)
> > > sentence is the key to testing the viscous
> > > coupling.   For in most cases
> > > we  are not dealing with viscous  couplings doing
> > > less than their share,
> > > but rather with hard-going viscous couplings  which
> > > don't have a problem
> > > at all in  moving the van  out  of the  test stand
> > > with  the engine just
> > > idling.
> > >
> > > Thus the really important thing here is not the van
> > > successfully leaving
> > > the test stand.  On the  contrary, the important
> > > thing  here is the  van
> > > not moving and staying put in the test stand with
> > > the G-gear switched in
> > > and the engine just idling.  If your  Syncro
> > > doesn't pass this test your
> > > viscous coupling is probably  worn out and  ready
> > > for a replacement.  Or
> > > put  the other way  round: as  long  as your van's
> > > viscous  coupling is
> > > working properly you will not notice your van has
> > > got one.
> > >
> > > As   soon as   you are encountering   problems
> > > with your Syncro   when
> > > cornering, in particular after a long and  fast
> > > drive, or  as soon as --
> > > despite  of power  steering --  steering becomes
> > > a  bit difficult when
> > > turning and the Syncro slows down considerably when
> > > going round a corner
> > > ... as soon as one or  more of these  things are
> > > happening, your viscous
> > > coupling is most  probably due  for  replacement.
> > > When  the tires start
> > > whining while cornering it might well be too late
> > > already ...
> > >
> > > I once had all of these symptoms and it was
> > > immediately clear to me that
> > > the viscous coupling was  the culprit.  But it
> > > took  some time for me to
> > > react, and it took some more time for the new
> > > viscous coupling to arrive
> > > at my door.  Should you ever encounter similar
> > > problems I would urge you
> > > to  immediately get under  your van and  remove
> > > the drive shaft between
> > > gearbox and front  diff.   If you  fail to do
> > > this  and wait  too long,
> > > severe damage to the  gearbox and/or front  diff is
> > > the probable result.
> > > Removing the drive shaft is pretty straight
> > > forward, just four bolts and
> > > nuts (13  mm) on either   end of the  drive
> > > shaft.   Then loosen  (just
> > > loosen, don't remove  them) the three nuts and
> > > bolts (17 mm) which hold
> > > the front diff in place, so the front diff can move
> > > out of the way a bit
> > > for the drive shaft to be removable.   Don't forget
> > > to again tighten the
> > > 17 mm screws.
> > >
> > > When   I  was shopping  for  a new  viscous
> > > coupling  (according to all
> > > reliable sources  I contacted they cannot  be
> > > repaired)  I asked several
> > > knowledgable people how long   a viscous coupling
> > > is expected  to last.
> > > Apart from "it depends"  (an employee at
> > > Steyr-Daimler-Puch  in Austria,
> > > the firm which  was producing the Syncros  and in
> > > particular the viscous
> > > couplings for  VW) the answers ranged from  "some
> > > 60,000 km" to "between
> > > 170,000  and  200,000 km".   Mine  was replaced
> > > after  150,000 km but I
> > > bought the Syncro with  80,000 km on the   tach and
> > > don't know  for sure
> > > whether  or not this  was still  the  first
> > > viscous coupling.   But I'm
> > > assuming it was.
> > >
> > > As for the  reason  why the silicone  in  the
> > > viscous coupling  gets too
> > > stiff and   starts  causing trouble   the people
> > > I asked  unanimously
> > > answered: to much strain.  However,  this is not
> > > referring to relentless
> > > off  road driving in  groundless mud, but rather
> > > to small but permanent
> > > differences in rotational speed between front and
> > > rear axle while doing
> > > normal on road  driving.  These differences  in
> > > rotational  speed can be
> > > caused by  such things as unequal  tire wear or
> > > different tire pressure.
> > > Tire diameters should be the same within a 2 to  4
> > > mm tolerance.  Or, in
> > > other words,  if you're measuring  the depths  of
> > > the grooves in  your
> > > tires, the differences should not exceed 1 to 2 mm.
> > >
> > > Thus  people not caring  tire   pressure and  tire
> > > wear,  people  having
> > > mounted different  tire brands on the front  and
> > > rear axles,  as well as
> > > people never routinely  using their spare tire so
> > > it gets  worn roughly
> > > the same way as the other tires are most  probably
> > > ruining their viscous
> > > coupling pretty fast.
> > >
> > > Removing the drive shaft as an emergency measure:
> > > If you  have  to, and provided  you're  slim
> > > enough, you  can remove the
> > > drive  shaft on the  bare ground (at least if
> > > it's  a Syncro 16"), just
> > > with a little help  of the  factory  jack.  In case
> > > your  driveshaft was
> > > balanced  in its current position,   it may be a
> > > good  idea to mark the
> > > alignment points of the flanges before removal.
> > > Then you'll have to use
> > > a pair of 13mm wrenches (due to space constraints
> > > only open wrenches are
> > > usable) to remove four bolts and  nuts at either
> > > end  of the drive shaft
> > > (sometimes the  nuts are  only  12mm).  If you
> > > want  to do it  properly
> > > you'll also have to loosen (only loosen,  don't
> > > remove!)  the three nuts
> > > and bolts (17 mm) which hold the  front diff in
> > > place via rubber stops,
> > > so the front diff can move out  of the way a  bit
> > > for the drive shaft to
> > > be removable.  However, when lying on the bare
> > > ground just below the van
> > > this might be  hard to  do.  If your  drive  shaft
> > > has got  this  rubber
> > > element in it  you may try  to simply use  a screw
> > > driver  to cautiously
> > > separate the two flanges at one end of the drive
> > > shaft.  Knocking gently
> > > at the flanges at the other end will then take the
> > > drive shaft down.  As
> > > to the rubber element: in diesel engined and FI
> > > vans the rubber element
> > > was facing   opposite sides.  Thus you'd   better
> > > take some  notes as to
> > > whether  the rubber element is at  the gearbox end
> > > or  at the front diff
> > > end.
> > >
> > > Replacing the viscous coupling:
> > > To replace  the  viscous    coupling you'll  have
> > > to pull   the  front
> > > differential first.  I don't think it's feasible
> > > to replace the viscous
> > > coupling right  under the van with the  front
> > > differential in place.
> >
> > Derek's Note:
> > Californians on the list proved otherwise so if you
> > want to leave the diff in there go ahead. Sam Walters
> > did it on the ground, but he indicated it was a pain.
> >
> > > In
> > > particular, reassembly would thus be much more
> > > difficult and would cause
> > > plenty of cursing.  And you'd have to drain the oil
> > > first.  By and large
> > > there is  no  witchcraft involved in  pulling  the
> > > front  diff,  but you
> > > should do it  with the van on a  lifting platform
> > > or above a grease-pit.
> > > And it takes two people as well as a floor-jack.
> > >
> > > First of  all losen but   don't yet remove the
> > > three 17mm nuts already
> > > mentioned which hold the front diff in  place.
> > > Then remove  the speedo
> > > cable  as well as the six  screws in each of  the
> > > inner CV-joints.  For
> > > this  screws you'll need  either a   6mm hexagonal
> > > or an 8mm multipoint
> > > socket.  If  you haven't done  it yet  you should
> > > now  remove the  drive
> > > shaft as   described above.   If   you have  a
> > > front  diff  lock (never
> > > officially exported  to  the  US) unplug   it
> > > electrically as  well  as
> > > pneumatically   (tag the pipes so  you  can't
> > > confuse  them later).  Now
> > > remove the  screw holding  the vent pipe  of the
> > > differential  and then
> > > remove the  three 17mm nuts  and bolts holding the
> > > front diff.  Get the
> > > floor-jack   in place and remove the   front and
> > > rear mounting brackets.
> > > Then  together with a   second person cautiously
> > > move  the diff forward
> > > along the skid plate and  out.  Look out for the
> > > diff lock if there  is
> > > one.
> > >
> > > Place the front diff on your workbench in such a
> > > way that the flange for
> > > the  drive shaft is facing  upwards.  You can now
> > > easily remove the ten
> > > 13mm bolts with which the housing of the viscous
> > > coupling is attached to
> > > the front diff without risking any  oil leaking.
> > > Lift the housing which
> > > is  containing the input shaft.  You  will  now see
> > > the viscous coupling
> > > itself  and a little spacing   collar sitting on
> > > top  of it.  Take this
> > > spacing collar, grease the top rim of it and again
> > > place it on the input
> > > shaft in the housing and slightly press  it with
> > > its greased rim against
> > > the bearing so it will stay there.  This  will
> > > greatly ease reassembling
> > > the diff later.  Now remove the old viscous
> > > coupling  and put in the new
> > > one.  Then apply silicone sealing compound to the
> > > contact flange of the
> > > housing  and, inserting the input  shaft into the
> > > viscous coupling, put
> > > the housing back in place.   Finally, gently
> > > tighten  the ten 13mm bolts
> > > crosswise, applying 20 Nm (15  ft lb.), and your
> > > front  diff is ready to
> > > be reinstalled.
> > >
> > > Perhaps you  should use the opportunity while  the
> > > diff is still sitting
> > > on your workbench to  check what has been caught
> > > by the magnet at  the
> > > oil drain plug.
> > >
> > > To reinstall the front diff in the van simply
> > > reverse the steps laid out
> > > above,  at the very  last  fastening the screws
> > > of  the front and  rear
> > > mounting brackets as  well as the  three  17mm
> > > bolts through the  rubber
> > > stops (apply 45 Nm (33 ft lb.) to these).
> > >
> > > Tools and torques needed:
> > >
> > > Installation of the front diff:
> > >    17mm socket and ratchet, perhaps with
> > > extension.  Use 17mm wrench to
> > >    counter at the other side, 45 Nm (33 ft lb.)
> > > VC housing:
> > >    13mm socket with extension and ratchet, 20 Nm
> > > (15 ft lb.)
> > > CV-joints:
> > >    either 6mm  hexagonal  or 8mm  multipoint
> > > socket  with extension  and
> > >    ratchet, 35 Nm (26 ft lb.)
> > > Drive shaft:
> > >    Two open 13mm wrenches (sometimes only 12mm for
> > > the nuts), 35 Nm (26
> > >    ft lb.)
> > > Acknowledgements:
> > > Special thanks go to Wolfgang Carolsfeld in Canada
> > > <wolfgang@island.net>
> > > who not only proofread this text, helped  me with
> > > some technical English
> > > terms I failed  to find in my  dictionary, and did
> > > the math involved in
> > > converting  the torques  from Nm  to  ft lb,  but
> > > who also successfully
> > > applied the underlying German version of this text
> > > to his Syncro to make
> > > sure it works :-)
> > > ------------------
> > > ---------------------------------------------------
> > > | Rainer M Woitok                  | Phone:
> > > (+49-9131) 85-27811,-27031 |
> > > | Regionales Rechenzentrum
> > > |                                   |
> > > | Friedrich-Alexander-Universitaet | Fax  :
> > > (+49-9131) 30 29 41        |
> > > | Martens-Strasse 1                | Telex: d 629
> > > 755 tf erl           |
> > > | D-91058 Erlangen
> > > |                                   |
> > > | Germany                          | Mail:
> > > Woitok@RRZE.Uni-Erlangen.DE |
> > >  --------------------------
> > > -------------------------------------------
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