Windshield wipers

[Bob Claffie]

Hi all, a couple generic Lucas wiper questions. Is there any way to change the sweep arc of the blades ? I want more swept area, say 135 degrees rather than the 90 degrees I have now. Secondly is it possible to get the wipers to park on the opposite side ? Thanks, Bob

 

[Geo Hahn]

You might want to mention what car this is for, though I can't think of a TR with wipers that only swipe 90 degrees.

Yes, just thinking about it I believe the park feature can be adjusted to stop anywhere in the normal swipe.

 

[Bob Claffie]

Geo, I specifically left off the particulars so as not to confuse people looking for "specific" answers I have a right hand drive Mini wiper set up installed in my Cobr* replica so you can see why I didn't want to confuse people with the facts. The 90 degree and 135 degree sweeps I mentioned in the original post were for reference only and are not necessarily very accurate.

Right now the wipers park to the right which is OK except the drivers wiper only travels as far left as true verticle which is directly in front of my nose leaving my left eye staring through the water covered part of the windshield. If I can get them to park to the left that would be a quantum improvement and if I could improve the sweep , even better. Bob

 

[Geo Hahn]

I recall an Indiana congessman who said "Don't confuse me with facts... my mind is made up".

I can only speak to how TR wipers are adjusted to park but perhaps yours from a Mini are similar. The park function is adjusted by loosening the hex-head screws that secure the top plate on the gear head, this allows that round center bit (with the red wire on it) to be rotated.

The rotation moves the 'dead spot' where the wipers will park. Normally the adjustment is slight as one is only trying to get the park spot at the very lower limit of the sweep but **I think** the adjustment could be taken to the extreme of causing the wipers to park at the far end of their movement.

Perhaps the real issue is the geometry at the base of the Mini wipers as the length of the that levered movement will determine the degrees swept.

Hope this helps, though I could be all wet.

 

[Bob Claffie]

Yes Geo, when I first installed the wipers several years ago I had to diddle with the park feature to get the blades to the bottom of the windshield. Somewhere, sometime back, I sorta recall seeing a description of these wiper motors that there was a cam or gear inside that was changeable and that would affect the arc stroke. For all practical purposes these motors are all alike/ interchangeable. I have to believe that the wiper stroke for a Spitfire and a TR8 are different and what I need to know is how that is accomplished.

I "think" I can change the parking side by turning the wheel boxes upside down so they are pushing where they were pulling , initially. Unfortunately my investigation on this subject was a long time ago and my memory is less than accurate.

Not trying to put the TR people on the spot but this IS the busiest of all the threads on this site and I figured I would get the most exposure. Bob

 

[Geo Hahn]

My recollection is that the round thing on the top of the gearhead contains a little (copper?) arm that tracks around a rotating conductive plate that has a non-conductive place on it. When you turn off the wipers that plate (which turns with the gearhead) continues to provide a ground for the motor (as the gearhead turns) until it reaches the non-conductive spot. Then, of course, the ground is interupted and the motor stops.

I imagine (but have never had occasion to try it) that it could be adjusted to put that 'stop point' anywhere you want it, i.e. moving it 180 degrees would park the wipers at the opposite end of their cycle.

Note: The above description is based on a late-TR3 or TR4 wiper motor which is always 'hot' and switched by interupting the ground. I think some Lucas wiper set-ups were the more intuitively obvious switching of the hot lead.

I think Randall is vacationing in Indiana else he would be able to explain this better or perhaps point the way to a solution. He really should leave a forwarding address when he is going to be away this long.

 

[Don Elliott]

If the wiper arms you have on this "Hybrid" have internal splines and if the wiper arms push down onto the splined diving heads, all you need to do is remove the wipers and arms lifting them up carefully with a screwdriver under the edge, make sure that the "park" is where you want it to be and push the wipers and wiper arms back down onto the driving splines. It won't change the 90 derees but you're wiper will clear the windscreen where you need it to clean.

 

[Bob Claffie]

Sure. Don, I could re-index the blades to wipe where I look but the down side is that they would then "park" half way up the windshield. When I built the car I didn't anticipate driving it in bad weather as I have alternate transportation, however, I have recently been caught out in a couple sudden downpours and as I have NO top I gets pretty dicey trying to navigate with water on my glasses and on both the inside and outside of the windshield, especially at night ! I could be much more selective about when I drive the Cobr* but --- Bob

 

[TR3driver]

I think Randall is vacationing in Indiana else he would be able to explain this better or perhaps point the way to a solution. He really should leave a forwarding address when he is going to be away this long.

Well, I still check in as often as I can; just happened to miss this thread. But you guys have already pretty well covered it : the park position can be adjusted by rotating the switch housing as outlined above. And changing the sweep requires changing the gear inside the motor (which will sometimes have the degrees of arc stamped on the gear).

It might be possible to modify a gear by cutting off the old post and installing a new post (at a different distance from the gear center), but I've never tried it myself.