1993 Corolla LE auto 1.8 liter 320,000 km

The windshield wipers on this poor car are struggling so hard that the wiper
motor is twitching the firewall in and out.  The binding is in the hubs on
the cowl.

The hubs look to be made from aluminum, as they are corroding a white
powder.  I took out the entire drive linkage in hopes of disassembling and
lubricating.  However, the drive arm is riveted on to the spindle.  There is
no circlip, so possibly the spindle is pressed in place and not removable.
This thing is so tight you can't move the hub by hand.

There is no oil port, so I sprayed some penetrating oil on the tiny crack
where the spindle exits the hub.  It still shreiked when the motor was
activated (without blades).  I then put lots of 10w30 on (perhaps one drop
went in) with the tip of a small screwdriver.  It is now quiet, however the
motor still looks like it's torquing slightly, a bit more than the reaction
to the linkage shifting, even without blades mounted.

Should I drill into the side of the hub?  I think the problem is binding
within the hub caused by the exfoliation and helped by unlike metals in
contact.  What are your thoughts on this?

Your expert opinion is welcomed.  Regards, Jack.