At 04:53 PM 1/26/2009, Matt Drew wrote...
>goes up to about 50% on the
>upstroke, then down . . . to below the frame of the windshield, coming
>to
>rest at the end of the downstroke on sheet metal.
>
>Is there an easy adjustment to correct the problem?

You need to remove the wiper arm from the shaft. There's a cap on the
pivot, and under that a nut (10mm wrench?). Pull the arm out against
the spring so it's pointing away from the windshield, remove the nut,
then pull the arm off (it should be easy, since it's slipping).

The arm is made of a soft metal, the shaft of steel. The shaft has some
splines which are supposed to dig into the soft metal of the arm. Since
it's been slipping, those splines are likely plugged up with soft metal
- you have to clean the soft metal out so those splines can get a grip,
otherwise it will just slip again. A dental pick works well.

Turn the wipers on/off so they're in the park position, then install
the arm so the blade is in the correct position, approximately parallel
to the bottom edge of the windshield. Tighten the nut firmly, but not
too hard (it takes only about 4 lb-ft torque). If you want, you can use
a bit of blue locktite (the medium strength stuff) on the splined part
before putting the arm back on.