Wiper Motor dead

[rogerowen]

Wiper motor not working although there is a small deflection on the ammeter as the switch is operated. The motor is fed by 3 wires,  a green wire carrying 12v + and a green/brown carrying 12v -. There's also a green/red cable. I cleaned the commutator and checked the brushes - but still no joy. I've now removed the motor and want to test with a bench supply. Am I right in thinking that I just need to supply power to the Green and the Green/Brown? Thanks.

52 on the diagramme.

[RogerH]

Hi Roger,

as you say GREEN - 12V

G/N and G/R - earth   one for slow and two for fast speed.

You need to use the earth wire that gives the slow speed (plus the Green) to make it work

OR both G/N and G/R _ the green

The red wire on top is the self park earth.

 

If it is completely &^%$£ then consider the TR6 14W.  These are more powerful and run very well.

 

Roger

[tthomson]

Hi Roger (Owen),

RogerH is correct, Green wire has + 12 volt supply, and both the other wires should be connected to ground.

If it doesn't work the problem will be either the brushes need replacing, a disconnected wire, or a burnt out winding. The brushes are fiddly, but replaceable! A disconnected wire can be resoldered, but a burnt out winding is more difficult. On two speed motors, the resistive coil (cotton covered) winding is the more likely suspect. It is wound on top of the lacquered copper field winding. It is replaceable with a 5Watt ceramic resistor of a bout 8 - 10 Ohms.

The attached PDF document is specifically relevant for DR3A motor that I received from another forum member (but I forget whom)

Kind regards

TT

Lucas DR3A wiper motors.docx

[keith1948]

Hello again Roger

The 2 speed wiper circuit must be one of the most confusing. RogerH and Tony have both said different. Roger has both wires for fast when on mine both are for slow. Tony has the link to an article written by Alan Turner where he has the fast wire connection as brown/green and both as slow. I'll just tell you what I have on my car and it works fine.

There are 4 wires exiting the loom next to the wiper motor.

The green wire route is from the fuse box to the voltage regulator in the right hand drivers footwell on the right side wall. There is a double connector. The green wire continues from that connector to a double bullet connector that appears out of the loom above the steering column. (a bit hard to find) It then continues and appears as one of the 4 wires next to the motor. This is the +ve supply from the battery.

The 2 wires coloured red/green and brown/green connect the motor to the switch on the dashboard. The switch has 2 positions. On my car the first position of the switch connects the red/green to earth for fast speed and the second position connects both the red/green and brown/green to earth for the slow speed. However NOTE that I have seen circuit diagrams that say the brown/green is the fast wire. To check you have the correct wire for fast, remove the end of the motor and look to see which wire connects to the self park wire. In mine this is on the right as you look inside. The red/green and red self park wires are soldered together. The brown/green connects to the field winding on the left. Do not connect only the brown/green (in my circuit) to earth for slow speed or you will burn out the wiring. If in doubt connect both red/green and brown/green to earth together to give you the slow speed.

There is a black wire from the switch that is the earth wire. Confusingly this also emerges as the 4th wire next to the motor and this is earthed to the bodywork next to the motor.

On mine there is another black wire that goes from the end of the motor to the bodywork. This is the earth for the self park mechanism. The red wire on the motor itself is the self park circuit. The motor self parks on fast speed hence the wire connected to the red inside the motor is the fast wire.

Hope this makes sense

Keith

[rogerowen]

Many thanks RogerH, TT and Keith - all very helpful. Think a burnt out unit is most likely to be the problem although I can't see anything screamingly obvious, will try some bench testing  tomorrow.

[tthomson]

Hi Roger (Owen),

Keith's point is worth considering, but to check the motor operates without causing damage to it,  the green wire connects to the 12 volt supply, and both the Brown/Green and Red/Green wires should connect to earth. In that way, you are not in danger of overloading it.

Kind regards

TT

[rogerowen]

Thanks TT,  just about to give it a try. Replacement could be expensive, although I'm intrigued about the idea of replacing with a TR6 type, these are affordable! I expect there's some mounting issues to overcome.

[stuart]

25 minutes ago, rogerowen said:

Thanks TT,  just about to give it a try. Replacement could be expensive, although I'm intrigued about the idea of replacing with a TR6 type, these are affordable! I expect there's some mounting issues to overcome.

You would need to fabricate a mount using parts from the TR6 mount, its not over difficult. Fitting kit number 48 https://www.moss-europe.co.uk/shop-by-model/triumph/tr5-6/electrical-system/wipers-washers/windscreen-wiper-system-tr5-6.html

Stuart.

[rogerowen]

Thanks Stuart - that's very helpful.

[rogerowen]

Fresh light of day - and it's pretty clear to see that the coil has burnt out. Picture not uploading (-200 whatever that means) - but I can see that a portion of the winding is black and not copper coloured like the rest.

[RogerH]

Hi Roger,

that black wire is the high speed cotton covered winding.   It may look bad but could still work.

 

Regarding the TR6 14W motor. It is easy enough to support the motor in the correct position. The motor is infinitely better than the DR3.

You can also keep the existing wheelboxes. 

 

Roger

[rogerowen]

43 minutes ago, RogerH said:

Hi Roger,

that black wire is the high speed cotton covered winding.   It may look bad but could still work.

 

Regarding the TR6 14W motor. It is easy enough to support the motor in the correct position. The motor is infinitely better than the DR3.

You can also keep the existing wheelboxes. 

 

Roger

Bingo - it's working! Will hang on to the TR6 one I've just ordered for a later modification (not telling the wife though). Next issue - one wiper spindle turns freely whilst the other is very tight. Also, the grease in the gearbox and on the rack seems dry - might be worth re-greasing, unless it's a special grease?

[stillp]

If it's burnt out, there must be a reason - are the rack and wheelboxes working freely, and was there good grease in the motor gearbox?

Pete

[RogerH]

Hi Roger,

the spindles should be free to rotate (no rack fitted). It may be worth romoving and either sorting or renewing it.

LM grease will work but the black moly greases may be easier in the cold wonter.

 

Roger

[stillp]

Sorry, my message above seems to have spent an hour in the Twilight Zone!

AFAIK the grease is nothing special, and certainly shouldn't seem dry. I'd replace it with any good lithium grease. TRy some thin oil on the tight wiper spindle - if that doesn't work you need to take the wheelbox out, but that's a struggle.

Pete

[rogerowen]

9 minutes ago, RogerH said:

Hi Roger,

the spindles should be free to rotate (no rack fitted). It may be worth romoving and either sorting or renewing it.

LM grease will work but the black moly greases may be easier in the cold wonter.

 

Roger

Thanks Roger, I'm applying lots of WD40 to the spindle in the hope that it will free up.

[rogerowen]

11 minutes ago, stillp said:

Sorry, my message above seems to have spent an hour in the Twilight Zone!

AFAIK the grease is nothing special, and certainly shouldn't seem dry. I'd replace it with any good lithium grease. TRy some thin oil on the tight wiper spindle - if that doesn't work you need to take the wheelbox out, but that's a struggle.

Pete

Thanks Pete, Yes, I'd like to avoid wheel box removal - looks like a job for the 'double jointed'! Hopefully copious amounts of WD40 will do the trick.

[stillp]

I'd use a thin oil. WD40 is a Water Dispersant.

Pete

[rogerowen]

2 minutes ago, stillp said:

I'd use a thin oil. WD40 is a Water Dispersant.

Pete

I'm actually using GT85, not making a lot of difference yet. Currently looking for a diagram to see if it might need lubricating at the lower part. I've got some 3 in 1 (red tin), might be worth a try. Even thinking about getting a fix on my variable speed cordless drill to help.

[rogerowen]

Drill didn't work (chuck too small), think there's an access panel under the wheel box which would allow me to spray some oil up to the lower workings.

[stillp]

3 in 1 should soak through.

Pete

[RogerH]

Hi Roger,

it will not work.

If you are going to get the little panel off then go a step further and remove the spindle.

The problem is that you have an Ali spindle running in a plastic tube. You may get it turning bit it never frees up properly.

Get in there and remove it - TRShop do nice replacements.

 

Roger

Edited August 14, 2019 by RogerH

[monty]

My wiper stopped a few months ago. Took the motor out, bench tested & it was fine. Thought it would then be the wheel boxes & the nightmare of getting to them but it turned out to be the rack was full of congealed grease. Rack out, cleaned & re-greased. Not sure what grease my repairer used but they restore & service many top classic cars as well as TR's so I am sure they used good stuff.

[rogerowen]

18 hours ago, stillp said:

3 in 1 should soak through.

Pete

How right you were - left overnight and it's as free as a bird! Saves me having to be a contortionist under the dashboard! I'll add this to my regular maintenance schedule.

Cheers Roger (O). 

[rogerowen]

14 hours ago, monty said:

My wiper stopped a few months ago. Took the motor out, bench tested & it was fine. Thought it would then be the wheel boxes & the nightmare of getting to them but it turned out to be the rack was full of congealed grease. Rack out, cleaned & re-greased. Not sure what grease my repairer used but they restore & service many top classic cars as well as TR's so I am sure they used good stuff.

Hi Monty, thanks - yes, same here - congealed grease on rack as well as gearbox. Is your profile picture an AA5A? passed my ppl in one of those many years ago.

Edited August 15, 2019 by rogerowen
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