[Vwdiesel] Walking timing belt

[Andrew .Libby]

Certainly pump bushings should be checked along with not over-tightening the
timing belt.  Belt tracking, although potentially related, is a different
issue.  It is easily adjusted by the orientation of the injection pump
mounting bracket.  To adjust the tracking so that it moves closer to the
engine the sprocket end of the injection pump needs to move *down* and the
end where the metal lines are attached to the pump needs to move *up*.
Moving the sprocket up and the metal line end of the pump down causes the
belt to track away from the engine block.  Therefore, when the pump bushings
wear, the belt does not tend to ride off the injection pump sprocket and so
the belt riding off the sprocket is not typically an indication of pump
bushing wear.  To adjust the pump mounting position on the 1.6 one can
loosen the two bolts that are behind the injection pump (three on the 1.9)
that mount the pump bracket to the block.  With those two bolts loosened,
the pump bracket can be moved up or down as necessary.  The bolt holes are
considerably larger than necessary to accommodate that action.  In my
experience, it is possible with a c-shaped wrench to access those two bolts
with the pump in place, but downright difficult.  Whenever the pump bracket
has been off or the pump itself is swapped it is very common to need to
adjust the tracking.  It really should be adjusted so that it does not rub
on any of the lips of the pulleys or on the back of the crank pulley as it
will wear significantly faster that way.  I actually cut a section out of
the timing belt cover and glued on clear acrylic in order to be able to
easily see that belt tracking is correct without removing the timing cover.

Andrew

On Thu, May 27, 2010 at 7:10 PM, Kneale Brownson <knealeski at sbcglobal.net>wrote:

> When you watch the engine run, is there a wobble in the vibration
> damper/timing belt pulley on the crankshaft?
>
> My 95 Jetta 1.9 turbodiesel had a wobble from the damping material in that
> pulley failing, and the belt would not run true.
>
> --- On Thu, 5/27/10, Chris Geiser <cfgeiser at gmail.com> wrote:
>
>
> From: Chris Geiser <cfgeiser at gmail.com>
> Subject: Re: [Vwdiesel] Walking timing belt
> To: "Joe" <joe at haasenpfeffer.com>, vwdiesel at vwfans.com
> Date: Thursday, May 27, 2010, 7:59 PM
>
>
> That should never happen - something must be loose... Pump mounting braket
> or rear/bottom bolt?
>
>
> Chris
>
>
>
>
> -----Original Message-----
> From: Joe <joe at haasenpfeffer.com>
> Sent: Thursday, May 27, 2010 6:31 PM
> To: vwdiesel at vwfans.com
> Subject: [Vwdiesel] Walking timing belt
>
> I've got an '82 Rabbit n/a and the timing belt is slowly trying to walk off
> the front of the injector pump pully.  The flanges on the intermediate
> shaft
> are holding it in place, but even THAT has a gouge in it and it's slowly
> eating the timing belt.  I did NOT install the timing belt, nor do I feel
> comfortable (at this point) in attempting it.  But if there is an
> adjustment
> I can do without having to pull the belt, I'm all ears.
>
> Joe
>
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