Wipers Park In Correct Place But When Operating Scrape Over Chrome work & Over Paint Work

[PointToPointer68]

Hi All,

REF:- 1988 XJ-S HE

I have stripped down the wiper mechanism cleaned & re-greased it, stripped & cleaned the motor but no new brushes were needed.
I did these jobs because I needed to replace the plastic parking switch (slide fitted to the motor/ mechanism housing) & thought it was an ideal opportunity to service the complete system.
The problem I have is that the windscreen wipers (both of them) park in the correct place, but when they are in operation they "sweep" too far down & one wiper goes over the black grill & the other over the painted area which meets the chrome work to the windscreen (this isn't a simple adjusting the wiper arms task).
The wipers normally park on the drivers side ( as I know there are the two systems Lucas & Electrolux).
I have looked all over the internet & the closest I have come to fixing it is from a Canadian owner who had a similar problem & said he adjusted the mechanism but NOT HOW.I have only tried adjusting the thread that has a locking nut on it, at the opposite end of the electric motor.
Doing this has had zero effect on the "working sweep" of the windscreen wipers.
I know I must have upset some sort of adjustment when servicing the complete system- But I have run out of any further ideas & wondered if anybody had had the same problem in the past & if so how did they make the adjustments?
Any ideas from fellow members would be very gratefully received as I'm at a total loss as how to proceed.