Wiper Issues

Post by **baz_d69** » Fri Oct 09, 2009 2:25 pm

Hi all,

I'm sorry my first post here is an issue, I have been lurking for a while. The site has been a great resource so far, but I need a few more specifics for this issue! I've got a 1956 Minor, which I got as a p/x. I've been trying to get it ready for its MOT, and found a few electrical issues. The horn and indicators (and semaphores for that matter) didn't work. Cleaning up all the electrical terminals and fitting a new relay sorted that (apart from the Semaphores, which I'm not too concerened about), but now I'm left with this wiper issue.

Does anyone know the wiring diagram just for the wiper circuit? I have 3 terminals on the wiper motor, terminals 1, 2, and an earth connection. I have a green wire, a black and green, and a black to earth. Now, from what I've read, the wiper is actuated by connecting the earth to terminal E on the little electrical unit on the firewall, which in turn is earthed. Now, my first issue is, that I'm getting a constant connection to earth, regardless of switch position. I've swapped to another switch which tested to be ok, but once installed had the same issue. I'll test the switches again later. From the above, am I right in saying it is Wiper Earth > Switch > Terminal E > Earth?

Also, I am getting 12V to the Wiper Motor, though I haven't checked the current yet. Another peculiarity is that all 3 terminals on the wiper motor, seem to be connected to eachother, I.e. I get continuity through all of them. Now, reading back through the post, that would imply I'd have a direct short through the motor right now.

The switch issue isn't concerning me as much as the 3 terminals being connected, is this typical of a wiper motor that is broken?

A lot of questions, thanks for any help in advance!

Baz

Post by **mike.perry** » Fri Oct 09, 2009 4:13 pm

First I assume that you have an early 948 Minor 1000 with the wiper motor under the bonnet and not a late splitscreen Series II.
Are you sure it is a 56 Minor as the wiring is different to the later cars with self park wipers.
The feed to the wiper switch is from the earth terminal (E) on the control box (black) and then to the wiper motor (black/green).
The live return wire (green) attaches to the back of the fuel gauge. Green is a common power supply cable so any green wire connected to the wiper motor will do.
Remove the wipers or spring them off the screen to avoid strain on the wiper rack and disconnect the wires from the motor and connect a wire straight from the battery to the live (green) terminal and a wire from the earth terminal to earth on the body. The wipers should now work, if so replace one wire at a time and check with the ignition and wiper switch on.

Post by **bmcecosse** » Fri Oct 09, 2009 4:15 pm

Welcome to the forum! May be worth disconnecting the wiper mechanism - so the motor can have a chance to run without any load. The terminals will seem to be 'together' if all you have is a simple continuity meter. You would need to measure ohms quite accurately to detect the resistance. It is a parallel wound motor - so the field coils are in parallel with the commutator. Yes -there should be 12 volts to the motor all the time - and it should run when earthed - either continuously if you maintain the earth through a switch - or just one revolution of the drive gear if you momentarily earth the connection. may be worth inspecting the brushes - they do wear down and are easily renewed. See section N10 of the Manual!

Post by **baz_d69** » Fri Oct 09, 2009 8:16 pm

Mike, I checked the documents, it's in fact a 1957. I don't know what you classify as late, but this one has semaphores, a dash mounted ignition switch, pull starter and as you said, the wiper motor under the bonnet (pass side), and no, it's not a split screen. Badges say Minor 1000. I'll try your suggestions.

bmcecosse, thanks, I'll check those too!

Post by **baz_d69** » Sat Oct 10, 2009 7:25 pm

Mike, I just re-read your post, are you suggesting running 12V to the green and and earth to the earth on the body of the wiper motor, or the black/green earth? Also, where does the earth which screws into the body go? There must be a reason for it to go back into the wiring harness rather than earth on the firewall?

I tried running - from the battery to the Green wire terminal (with the wipers taken off and all wire connections taken off) and + to the earth on the body, but nothing happend, no noise, nothing. I'll try the same again, but with the black/green wire terminal also earthed to + on the battery.

I took the wiper motor off to have a look inside, clean out the old grease and inspect the unit, and noticed the cover which sits on top of the worm/final drive (which unscrews from the top) has a brown wire, and a metal connection on the inside. My logic tells me this is a self park mechanism, it must over ride the switch until the metal connection contacts the peg on the final gear drive. If this is the case (and I may be completely wrong), I should match the connection back up with the peg when I put it together again, as I didn't take notice where that connector was placed when I took the cover off...right?

Post by **baz_d69** » Sat Oct 10, 2009 7:59 pm

Just came back in from doing the above, I connected terminal 1 (black/green) and earth together to + on the battery, and terminal 2 (green) to -. The first time I got a very slight click. Other than that, nothing.

Post by **bmcecosse** » Sat Oct 10, 2009 8:06 pm

Check the brushes! But really - another motor will be the quick answer - and look at that one later to see if it can be fixed.

Post by **baz_d69** » Sat Oct 10, 2009 8:38 pm

Well, I've already disassembled it and got all the parts soaking in white spirit. Brushes need replacing, is there anything else in there that can be replaced/checked while it's open?

Post by **bmcecosse** » Sat Oct 10, 2009 9:07 pm

Check the field coils are ok - and clean the commutator!

Post by **mike.perry** » Sat Oct 10, 2009 9:49 pm

The 57 Minor has "clap hand" wiper arms and no self park. The wiring diagram only shows 2 wires to the motor. The 1098 Minor has parallel wiper arms with self park. This motor has 3 wires (2 earths) the extra to operate the self park which is the rotateable circular unit on top of the motor.

Post by **baz_d69** » Sat Oct 10, 2009 11:22 pm

Thanks for your help so far, bmcecosse and Mike. Mike, that corresponds with what I was theorising. Here is the state of the motor when I first opened it:

and this is what the brushes looked like:

I've cleaned and rebuilt it now, just need to replace the brushes. Do either of you have any suggestions which supplier to get them from?

Post by **baz_d69** » Sat Oct 10, 2009 11:23 pm

Btw, Mike, what are "claphand" wipers? At a guess, is it wipers which move towards eachother (i.e. a line of symmetry), rather than in the same direction? If so, those are the wipers I have. Someone must have retro-fitted the later wiper motor to the car.

Post by **bmcecosse** » Sat Oct 10, 2009 11:37 pm

Bull Motif have the brushes ..... http://www.morrisminorspares.net/shop_item.php?ID=3607

Post by **baz_d69** » Sun Oct 11, 2009 12:38 am

Thanks, I have ordered a set @ £2.50. With VAT and postage, it came to over £7, that's pathetic.

Post by **PSL184** » Sun Oct 11, 2009 12:46 am

blame...... a) Mr Brown & b) royal mail .....

used to be able to pick them up at 40p a pack from the local hardware store before that went by he wayside....

Post by **baz_d69** » Sun Oct 11, 2009 1:12 am

You're looking for that dynamo spring, right? I think I've got a spare dynamo..

Post by **PSL184** » Sun Oct 11, 2009 9:19 am

Thanks Baz, I'll let you know - I may have located one nearby....

Post by **mike.perry** » Sun Oct 11, 2009 11:09 am

Baz, It looks from the photo as though you have self park wipers. Is the circular disc over the gear wheel separate from the cover?
What pattern wiper layout do you have?
As I said earlier, self park wipers were only fitted to the 1098 so if you have them on a '57 then they must have been fitted by a previous owner

Post by **baz_d69** » Sun Oct 11, 2009 11:57 am

Mike, yes the circular disk is seperate, and connected via a red wire to the windings. This is a picture of the car:

The wipers move away from eachother. As per my previous post, does that mean the earth terminal on the motor can be wired directly to an earth instead of going back into the harness?

Post by **mike.perry** » Sun Oct 11, 2009 12:55 pm

Let's try page N.26. I may have been wrong about the self parking but usually there is someone to correct your mistakes before you have pressed the submit button!
There are 3 connections to the wiper motor. A green live directly from the ign. fuse. The earth from the control box term E which is black to the switch and then black/green to the motor and then an earth black which goes to the car body, I assume.
If you have tried wiring the wiper direct to the battery with no success then I would agree that it is a motor service or replacement.
Unless you have trouble with the rack. Try disconnecting the rack and testing the motor