Initially I chose to use a set up from a Toyota Celica. Mostly because Garry Pegler still has the wrecks down the back of his place that I could raid and secondly because you will recall from the aircon I have the entire front section wiring loom. You will also remember that when I was trying to work out all the wiring for the aircon that I traced every one of those wires and labeled them......thank goodness......that hard work will all pay for itself now as I try and work out the wiper wiring.
Here is a picture of the set up.
This is the motor
....and these are the two drives. These are the bits that your wipers bolt on to.
The overall set up is quite long but its easy enough to shorten up as the sweep of the wipers is determined by the stroke of the motor and radius of the short arms that come off the back of the two drives shown above. So what that means is you can shorten the long connecting rods without any impact on the operation of the wipers, you just cut a chunk out of the middle to suit, then weld them back together again. But........its not quite that easy........
You see on the Celica, the wiper motor and drive is all mounted at the top of the firewall under the bonnet and are in full view when you open the bonnet. Now on hot rods, wiper motors and mechanisms are hidden. Looking at this unit I couldn't get it clear in my mind just how I could mount the motor behind the firewall and still get it all to work as the angle of the drive on the motor in relation to the arms was not going to suit. Sure I could have gotten there if I persevered but why make life hard for yourself.
Another trip to Pick a Part and I located this little beauty out of a Holden Vectra. Its an all in one unit that will still need to be modified but it will fit neatly up under the dash and out of view.
Whats more at just on 500mm (1/2 a metre) its really compact and shouldn't need much work done to resize.
So anyway just how do wipers work?
In effect you have an electric motor that spins over. It drives what is known as a worm drive (a kind of spiral) that interlocks with a wheel that has teeth on its edge. By doing that the motor that is spinning a long shaft has its twisting action converted to the rotation of a large flat wheel.
In the picture above the motor is the black tube off to the right. When it runs it turns the screw like rod you can see at the bottom of the picture. Then (I should have cleaned it so you could see it) under all that gungy looking grease on the white wheel there is teeth that interlock with that shaft....so the shaft turns.....the worm drive spirals outwards......and that pushes on the teeth on the wheel which in turn goes round and round. With me so far?
What happens then is the plastic wheel has a shaft through its centre that has an arm attached to it.
The picture above is the other side of what we were looking at in the previous picture. The shaft that I mentioned was attached to the white plastic wheel can be seen protruding through the hole in the flat steel coloured mounting plate (roughly centre of the photo). Its a bit obscured by the arm in the foreground, but you can see it has a goldy coloured bracket coming off it.
Remember the white wheel is turning round and round so the shaft is doing the same........and of course the gold coloured bracket is also rotating.....a bit like the arm on a clock.
Now thinking about the wipers on your own car....they go backwards and forwards not round and round....thats where this conversion happens. You see the plastic looking black fitting that attaches to the gold bracket is over to the right when the gold bracket is at the 3 o'clock position but as it rotates to the 9 o'clock position it moves over to the left.....then as it returns to 3 o'clock is back over on the right.....we have now converted rotational movement to left, right, left, right. Away go the wipers! Easy as that!
Actually here's a video that demonstrates all that a bit better.
Well that's not quite all there is to it, I have just finished sorting out the wiring tonight to control the self parking, intermittent (4 speeds), the wipers (2 speeds) and the washers.
That will be in my next blog.
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