240Z - Random Wiper Arm Parking Position

[acf321]

Hi Folks,

 

Hopefully as the header suggests, when I switch the wipers OFF on my 71 240Z, the arms tend to either; 1) stop right in the midst of the stroke, or 2) move for another stroke or two and then stop in a totally random position on the windshield. To get them to park in the correct position just above the cowl panel requires the skill of a surgeon and patience of a Saint.

 

Does anybody know whether this is a switch related issue, or wiper motor, or relay (wherever that might reside?) or other? Very keen to have this issue resolved, not that I plan on doing a whole lot of wet weather driving, but its just one of those annoying glitches I wish I had remedied.

 

Cheers

 

Adam

[Zedman240®]

From memory, it might be the "timing" switch in the wiper motor itself. Might have to open it up and give it a good clean. I may have it mistaken with something else but if I'm wrong, I'm sure someone will correct me!

[Scoota G]

Does it work on intermittent?

[acf321]

Hi Scoot,

 

Yes, it works on intermittant and full speed, but when I turn the wipers to the OFF position, they stop in any given position on the screen, 99% of the time not where they are intended to do so. Not entirely sure what I need to do to get them to part themselves properly when the switch is turned off.

[luvemfast]

I can recall a similar issue in some previous Z's.

But the biggest question is.......

WHY ARE YOU DRIVING YOUR Z IN THE RAIN?

[WA240Z]

Firstly, Luvemfast raises an excellent question. 

 

On the '73 car when you switch from intermittent to off the wipers complete another two sweeps across the screen then settle in their spot at the base of the windscreen. So the continuing to wipe thing is normal. I would firstly check the mechanical side of things. Make sure there is no play at the base of the wipers or at the motor. Are both wipers in unison with each other?

[Cozza]

Intermitant? I didnt think 240's had intermitant, my 9/72 doesn't. Have you replaced the wiper motor and/or switch from something else?

 

If its original i agree with Zedman the parking mechanism is within the motor itself.

 

Good luck

[gav240z]

I thought this was a feature not a fault... I seem to recall my previous Zeds having less than stellar wiper motor performance.

[Scoota G]

Mine do a similar thing in the black one. I tried swapping motors over and it did nothing. To get mine back to zero i have to leave them on intermittent and press the washer button. Weird much?

[Riceburner]

Firstly, Luvemfast raises an excellent question. 

 

On the '73 car when you switch from intermittent to off the wipers complete another two sweeps across the screen then settle in their spot at the base of the windscreen. So the continuing to wipe thing is normal. I would firstly check the mechanical side of things. Make sure there is no play at the base of the wipers or at the motor. Are both wipers in unison with each other?

 

My 11/73 also has intermittent setting, pretty luxurious ey!

[dalee]

while the rest of us just manage with the 2 speeds, slow and that might be a bit faster

[acf321]

Yeah OK ....

 

yes .. you got me ... its REALLY slow setting and LESS slow setting... NOT intermittant, and Billy when i switch it off, it does the old two strokes before settling where it should not...

 

I might just have a fiddle with the motor when i get the car back from James, suspect its a loose wire or something.

 

On this point, does anybody know a stockist of carbon brushes for these motors? Thought i might have a fiddle and most likely will need to change the brushes and springs ... question is, where do I get these?

 

Adam.

 

 

 

 

[Zedman240®]

With the brushes, you may have to go to a power tool repair place and look for similar shaped brushes or buy bigger ones and cut them to fit.

[Scoota G]

You would not believe it but after a year the wipers on my black Zed started working properly today. I suggest you talk badly about the wipers on the interwebby and perhaps they will start working correctly as mine did.

[Zeddophile]

How many wires to into a Zed wiper motor?

 

On an Alfetta, there is one wire that receives power whenever the ignition is on.  This power goes into a contact inside the gearbox part of the motor which rubs against a metal circular disc attached to the main worm gear, and that disc has a wedge shaped section cut out of it.  Then there is another contact which goes into the motor itself that also runs on the metal disc.  When the ignition is on, power runs through the metal disc, and rotates the motor until the contact reaches the section of the disc that is removed, which of course breaks the circuit and stops the motor - hence the 'park' position.  No power on this wire means no self parking, likewise a buildup of old hard grease on those contacts will prevent current flow.  The latter is probably more likely, happens to many things electrical, including the headlight switch contacts on my 2000 Discovery.  Grease was so hard I had to scrape it off with a screwdriver, and then lightly sand the contacts - contact cleaner wouldn't budge it.

 

On the topic of really slow wipers, it's usually pretty simple to speed them up, you just need to add relays on the input wires to the motor, one for each speed.  Normally nothing wrong with the brushes, simple matter of voltage drop in the factory wiring that only gets worse over 40 years. 

 

An easy way to see if this will help is as follows:

First, lift the wipers off the screen (so they don't drag across a dry screen and scratch it)

Second, unplug the wiper motor, turn the ignition on, and determine with a test light if any of the wires on the car side of the plug have power (this will be the park wire, if it exists).

Third, turn the wipers onto low speed, and find which terminal now has power to it, and remember which one it is.

Fourth, plug the motor back in, and observe the speed at which the wipers are moving.  Then run a decent piece of wire (4mm would be good) straight from the positive terminal of the battery into the wire you identified as the low speed power input (while wipers are still going) and they should speed up considerably if voltage drop is the issue.

 

A couple of notes here: if you don't unplug the wiper motor while testing, you will often also see voltage with a test light at the earth wire, hence safest to unplug it. 12v straight to earth is less than ideal  .  Also, if you wish to see how much your high speed will increase by, after steps 1, 2 and 3, flick the switch to high speed, and you should find the low speed wire is no longer powered, but a different one is now powered.  Repeat step 4, but obviously using high speed on the switch and the wire you determine to be its input.

 

I went from wipers that you timed with an hourglass to wipers which are comparable to all but the most modern cars...

[Zedman240®]

To fix my wipers, I did the Honda Civic motor conversion, but originaly my wipers were just slow. Found out the linkages just had dried grease that made the arms nearly impossible to rotate. Stripped, cleaned and they are like new now. You may just need to clean the pivot points on the arms and clean the motor.