Wipers Want to Work but Wont.

[Sam_Finlay]

My pick-up has been sat for six months while I worked on the rust and is back in a roadworthy state other than the wipers not working.

Checked the power supply - fine, dismantled the worm gear and although the grease is a little thick it also works fine. So I disconnected the drive cable to the blades and took the end off the motor casing to check the bushes etc and thought to test it with the end open to see if I could spot what is happening. A short video is attached. The rotor starts to turn when juice is applied but it is almost as if it needs a bit more umph to get it to go and keep turning. Does that make sense to anyone? Are the brushes excessively worn? I'm a bit stumped as to what is wrong and haven't found an answer on the old posts yet. Any ideas??
Short Video of the problem here http://youtu.be/tFOZni4Tc8w

[charlie_morris_minor]

sorry if this is a silly question, it certainly is not meant to be..when you were testing to see that the motor worked you did have the cover plate on the gear end, as that needs to be in place or the motor will not turn very far.

[mogbob]

Sam
Charlie's question needs to be answered first, before the "next course of action " can be discussed.

In the meantime however, the brushes are worn but not to the stage where you need to worry.When they
get very near the metal holders ...that's the time to change them.Although not pictured in your short video
I assume you have an unbroken insulating card that keeps the arms separate ?

Bob

[Sam_Finlay]

No - not a silly question Charlie. I could hear the motor kick / engage but not turn while the end plate was still in place so took it off to investigate further. The first thing I did was grease the end of the rotor shaft that's supported in the end plate. Made no difference. Thought that the drive mechanism to the wipers may be sticking so disconnected that from the drive. No change.

I then disassembled and cleaned the armature contact with a bit of 600 grit emery paper as it was a bit black and bolted it all back up again. Still didn't work, so unbolted it again and clamped the body to the gear section, to keep it all together and shot the video. If the rotor turned and then stopped because it had moved off centre and was shorting out then I would have seen that but it's the fact that it's sort of wanting to turn but wont that is confusing me. Almost as if it isn't getting enough power yet it is getting hot. The insulation card seems to be fine by the way. Or at least there is one.

It has to be something basic and me just being ignorant that is the problem. Please educate me and I'll have another look at it later today. Thanks for the help.

[Neil MG]

You have got power on the other lead I assume? I can see it is connected but it also needs to be live.

[rayofleamington]

firstly don't let it get too hot - ie.e. don't leave it stalled and powered up for more than a second and leave it long enough to cool down in between.
Excessive heat will break down the thin varnish-like insulation on the windings and that will cause them to get worse and hottere until it is completely dead.

Firstly can you turn the motor freely by hand?
If so, what happens if you turn it when powered up? i.e is it the same for 360° or does it have some good bits and some bad?

[Sam_Finlay]

You have got power on the other lead I assume? I can see it is connected but it also needs to be live.

My wiring diagram says it comes from the switch on the dash before it goes to earth on the other side of the same switch so it can't be live surely?

But your comment encouraged me to get in behind the dash to check and found that the heater had also been connected up to another terminal on the back of the wiper switch. That didn't look right so I traced the heater wiring through ( what a pain ) removed the offending connection and took it straight to earth elsewhere. Result - though I don't understand why, but both the heater and wiper motor now work on demand with a click of the right switch.

I suspect though that the wiper motor working now is more likely to be as a result of filing the bushed flat, polishing the armature to remove all traces of rust and re-greasing everything before reassembly. I have now found that the reciprocating cable that powers the wiper cogs refuses to move in the guide tube. It has been removed and is pickling in release oil while fixed in the vice for the night in the hope that I can fit it all back together tomorrow morning while there is a wedding on somewhere.

Chances are that it was this seizure that caused the motor to lock up in the first place. This then did something to the motor that caused it not to want to work. No idea what but thanks for the help as it now appears to be a mechanical issue I can resolve tomorrow.

While getting in behind the dash board I also found that the wiper wash is pumping water all round the inside of the dash when in use and that the heater pipes to the windscreen vents have fallen off so alls well that ends well. Just more things to do in the peace and quiet tomorrow.

[mogbob]

Sam
Once the pickling has done it's work can I suggest you temporarily remove the wiper arms.
Regrease the cable with fresh grease and put a reasonable size screwdriver through the hole
in the connector at the cable end.
This will enable you to run the cable back and forth ,as you insert it, as well as slightly rotating
it to get the cable through the wiper wheel boxes.
Glad it's sorted.

Bob

[Neil MG]

Sorry, my comment was not correct.

What I should have said is that the motor has a permanent live connection and is earthed both by the body and the switch. Of course it is live on the video as you are getting a spark! The permanent live should be connected as well as the casing earth and then the motor can be tested by earthing the terminal. As you quite rightly say the motor has two earth connections not two live connections. My point was that all three have to be connected for the motor to work.

Anyway you sorted it now, which is the good news! And if my comment prompted further improvements then all the better - good for forums!