"They don't always park themselves now...."

Parking wipers?  Two speeds?  Wow, what will they think of next?   

Had the same issues, and yes, easy to tear apart and repack with a good white grease and should last a while.

Thanks for the advice.  I pulled it all apart pretty easily.  The grease inside was a dried, sticky mess.  Cleaned it all off and re-greased it and the cable and the wipers are much better.  They don't always park themselves now, so I guess a new switch is in order but not critical yet. 

I'm with CTR here, suggesting giving the wiper box and bulkhead cable some maintenance. Its everso easy, just nuts n bolts, so simple you don't even need a Haynes Manual.

My tip is remember to pop off the arms from the splined lug, otherwise as you pull the cable out from the bulkhead tube it'll spin the arms round like mad and possibly scratch or get caught on your windscreen. You need to prise the arms off carefully, just gently ease them off with a screwdriver. Sometimes the splines can look white and crusty beneath. Careful not to damage the splines. LM grease is good for repacking the wiper motor and along the cable. If you do get into problems; wheelboxes, rubber bushes, arms and new blades are all easily available, just do a product search 'wiper'.

Hah, normal <> desirable

My 1994 works ok when it's raining heavily, but will stick straight up when it's misting in a show of typical British humor.  The humor part comes when I have to reach out my rolled down window trying to hit the wiper with my hands at speed.

Every wiper works slow on a dry windshield. It's when the glass is wet and they wipe slow that you have a problem.

How do they work on a wet windscreen?

Mark, do your wipers work on both speeds? I have worked on a couple of 90 plus cars and the wipers were slow. One even only worked on one speed. I removed the wiper assembly and cleaned the motor and replaced the brushes and flushed the wiper rack. The grease gets old and hard and slows things down. Once flushed cleaned and greased they work fine. The wheel boxes should be flushed with something like PB Blaster and lubed with a light oil. You may want to order a park switch while you are at it. They sometimes break while working on the unit.

CTR

It happens on my 67 although you could be in need of new brushes or the armature needs cleaning.

My new to me '93 mini wipers work, but they go REAL slow on a dry windshield.  I just got her inspected and it was pretty funny.  Is this weak wiring connections, a weak motor, normal on a dry windshield or is there some other common problem I can chase down?  Mark