I have a 1970 Cutlass Supreme convertible, I purchased the car in July 2014 knowing that the wipers did not work so replaced the motor, wiper still did not work, sent motor back for replacement, then motor worked, however, when wipers turned on washer motor would engage without pressing washer switch button and would stay on until the wipers were turned off. So all my local car club members said it must be the wiper unit. Replaced wiper unit with new still have same problem, sent unit back for replacement, still have same problem. So that could only mean the switch could be faulty, replaced switch still have same problem, returned and replaced wiper unit switch still have same problem. The switch is grounded correctly, I think. so I have replaced everything 2 to 3 times but still washers will not turn off on the proper cycle. I find it hard to believe that all the units replaced could be faulty. One of my club members told me that there are two springs in the washer unit part he said to move springs left to right that might be the problem, however they are factory set, so i am not comfortable doing so. Just a thought, i know the cam on the pump has to e set correctly when it is married to the motor unit, however this must be correct or else it would not pump when wipers are turned on. Please help i am getting very frustrated with this problem.

 

You could have ruled out the switch by simply unplugging the washer plug.

Sounds like these units are coming with the washer drive finger stuck on the drive cam.

I'd pull off the washer unit and disengage it.

From your description I'm ASSuming that you are buying wiper motors with the washer pump attached -- using a different washer unit, instead of the same one over and over, would have been the first thing you'd have tried... Right?

- Eric

Oh, and welcome to ClassicOlds!

 

The Chassis Service Manual has a very nice precise method laid out for diagnosing wiper/ washer ills.

Surely you have one of those? Or can get one? WELL worth it even for this one task.

 

Thank you for your quick response. First off I must tell you that this is the first classic vehicle that I have owned so please bear with me. No the units were purchased separately, they did not come as one unit and they appear to match the original. You advise me to pull off the washer unit and disengage it, yes that would cure the problem of the washer pumping all of the time, but I need washers. So is there a trick to getting the unit married back together whilst still on the vehicle? I don't know what you mean by "dry finger stuck on the cam drive". So do I just pull off the washer unit and replace it and hope it engages in the correct position. Sorry if I sound a bit vague as I said this is all new to me. Very much appreciate your input. Also thanks for the welcome to ClassicOlds

PhillK

 

thanks for your reply, no I do not have a Chassis Manual Have had a hard job finding one. My wife just found one on eBay so should have it by next week.

By the way this is my first Classic Car so am learning a lot!!!!!!!!!!! even at my age!!!!!!!!!!!!!!!!

Thanks PhillK

 

Okay. This is a very strange problem.

If you've changed BOTH the wiper motor AND the washer pump -- what? -- four times, I think, and you've had the same problem with each setup, then you HAVE to question whether it's something about the car and not the motor / pump.

If you've only changed the motor, but not the pump, that's a different story.

How long have you run the wipers each time before deciding that they're no good?
Have you run them long enough to go through the several cycles that the washer pump is committed to once it's engaged?
If not, then go do that now: Turn on the wipers and let them run with the pump running for at least 30 seconds, if not a minute.

Next, you need to pull of the washer plug, thus disabling the washer pull-in coil, and run the wipers again.

If the pump still stays on, even after 30 seconds to a minute, then shut it all off and remove the pump from the motor (four screws if I recall, watch out for the little ground strap), and observe how the activation finger is made to engage the cam when the washer coil is powered, and then stays engaged for a full cycle before releasing.
See whether there is something interfering with the release.

If none of this helps, then get on eBay and buy an original used 1970 Chassis Service Manual and Fisher Body Manual.
In your year, the wiper system was addressed in the FBM and not the CSM, so you have no way around the fact that you need both.
Also, your year is one of the most desirable, so, unfortunately, manuals will be the most expensive.

In addition to the actual original manuals, you may wish to acquire digital versions (which are usually not scanned with perfect clarity).
I recommend joining the non-profit Auto History Preservation Society (at WildAboutCars.com) for about $20 a year, which will give you full access to downloadable versions of your manuals, as wall as many others, and many other things.

The chapter on the wiper motor is long and complicated, because the wiper motor is a surprisingly complex little piece of technology, but I would recommend reading it over carefully, and then returning to your car, where you'll be able to figure this out without much trouble.

- Eric

ps:
You can't be that old if you've never owned one of these cars before, unless you started driving at forty.