Wiper wheelbox S1 vs S2 vs S3

The wiper system on my 1972 XJ6 Series 1 is a bit of a hodge-podge. The motor is 75967B and this is apparently a S3 model. One wheelbox is original Series 1 C28005 which is no longer available.

I had a broken wheelbox so I substituted a Series 2 one

Here is the problem … the wiper arm sweep. When in park position, both arms sweep 180 degrees, well past the end of the windshield. The arms remain roughly parallel so it appears that the gearing in the S1 vs S2 wheelbox is identical, or very nearly the same. I’ve been told that the sweep of the S1 motor is 120 degrees, and the sweep of the S2 motor is 125 degrees. Since the windscreen is exactly the same in the S1 and S2 (isn’t it??), I assume that either the S1 arms sweep a little bit more, or the S2 wheel has very slightly altered diameter/gearing.

Is this small sweep difference due to different gears in the S1 vs S2 wheelbox?
Is the too big 180 degree sweep using the S3 motor caused by a significant gearing different from the S1 originally in the car?

There is some difference in windscreen design, but the sweep angle should be the same…

However, have you tried the standard approach by repositioning the wiper arms on their spindles…?

xj6 85 Sov Europe (UK/NZ)

You need to use the parts for one model together. I ran a S3 wiper motor in my S1, but the sweep wasn’t right until I also changed the spindles to the matching S3 type. Once that is done the S3 parts do work better than the original S1 parts (aka the St Vitus Dance).

Thanks Nick … that’s what I was afraid of since swapping the wheelboxes is rather difficult. I previously tried to fit an S3 wheelbox and they are larger and wouldn’t work with the existing hole in the body. What experience did you have fitting in the S3 wheelbox.

I’m pretty sure I didn’t have to expand the holes in the bodywork. Just need the dash top out and a bit of fiddling around. Mind you, it’s 10-15 years ago since I did this now.

Does the S3 require different LH and RH wheelboxes? This is what is listed at SNG:

Apparently AEU2589 (RH) is listed in the original Lucas parts book as for “the driver side”. Thus in a British car, not an import, the driver side implies is it RH – on the right side of the car. However, in a USA LHD car, should AEU2589 still be put on the RIGHT SIDE of the car, or should it be installed on “the driver side”, that is on the LEFT SIDE?

Also, does the little aluminum cap that covers the S1 spindle also fit the larger S3 wheelbox?

The S3 wheelbox also attaches the wiper arm with a nut instead of just the splined top of the S1 (which is only push down, not screwed down fastening). Does this change how the alum cap fits?