The '89 240 wipers don't run smooth like my '93 or my '86. I disconnected the wiper motor from the wiper arm under the passenger dash..behind the glovebox. I wanted to see how difficult it was to push the wipers by hand. It's pretty tough. I can see why the motor might have trouble. Is there some sort of way to troubleshoot or grease or something? Anyone else fixed this type problem?
Cabbie2169

Check the bolts that hold the wiper mech to the firewall and make sure the pulley/cams are lined up evenly. Then see if the cables are tight. You can lube the wiper arm shafts by drilling a 1/8" hole in the side of the shaft and injecting white lithium grease with a syringe (monoject type for wood glue is good)and cap it with a small blob of RTV.

The wiper mech is fairly basic and quite durable. One problem I've had is the permanent magnets in the wiper motor separating from the casing of the motor, fouling the armature and causing noisy operation then jamming.

Also excessive end play in the motor armature can cause problems (there should be a screw adjuster).

Dismantling the motor is quite simple - if the armature is bright and shiny, look for a loose magnet - it may come out with the armature. If this is the problem thoroughly clean all parts, scrape the inside of the motor casing to remove the old adhesive (but check first to get a good idea where the magnet needs to go back) clean up the magnet and use stud and bearing /thread lock to stick it in place.

I think it's the motor that's making the noise and stiff movement. After pinning the wiper arms up, the whole wiper mechanism moved freely...(with motor disconnected).

When I started motor...it made a loud purring noise and didn't sound smooth. Perhaps it's the armature problem you've described.

Cabbie2169