Lucas DR3A wiper motor

[Grahamgl]

Gentlemen,

I have been offered a Lucas DR3A wiper motor for my 4A. However, it is not the 75568A, which is the model number of the motor according to the one presently on my car. Can anyone please tell me if a Lucas DR3A 75607B is a two speed model and if it would be a suitable straight fit replacement for my 4A? I haven't seen the item as it was offered me via the internet.

Thanks

Graham

[AlanT]

The only important things are the sweep-angle and does it run on 12V.

 

The sweep-angle is stamped on the big gear wheel under the top-cap. You need 120 degrees.

You can fit a 120 wheel to any motor BUT they are rare. If this is a 120 motor I will buy it if you don't.

May be interested no matter what angle it is.

 

It's quite easy to modify ANY DR3A for two speed operation. I'll do it for you if you want. Send me a PM.

 

Here is a video of an ordinary DR3A running two-speeds. You can see a green resistor used to achieve this.

https://www.flickr.com/gp/90670218@N04/7jD8J3

 

If you want a 120 motor in first class order I have one on eBay at present.

Edited October 28, 2014 by AlanT

[RogerH]

Hi Graham,

be careful of the part numbers DR3A may well be a single speed motor. The DR3 being the two speed jobby.

 

http://www.scparts.co.uk/sc_en/english-cars/triumph/triumph-tr2-to-tr4a-1953-1967/electrics/wiper-motor.html

 

Check out first

 

Roger

Edited October 28, 2014 by RogerH

[AlanT]

You cannot take any notice of the number on the plate. These plates all get swapped about at random by scrap dealers.

You must check the wheel.

 

I forgot to add that no matter what condition your 75568 motor is in, I will offer serious money for it.

[stuart]

Quick check for original 2 speed is if there are 3 wires going directly into the motor casing at the top of the main body or in the case of Jaguar and Daimler fitment then 6 wires.

Stuart.

[AlanT]

6-wire or 3-wires does not matter. It's easy to re-wire one to the other.

 

The wires either join up inside the case or outside the case.

[Dave Larnder]

The only important things are the sweep-angle and does it run on 12V.

 

The sweep-angle is stamped on the big gear wheel under the top-cap. You need 120 degrees.

You can fit a 120 wheel to any motor BUT they are rare. If this is a 120 motor I will buy it if you don't.

May be interested no matter what angle it is.

 

It's quite easy to modify ANY DR3A for two speed operation. I'll do it for you if you want. Send me a PM.

 

Here is a video of an ordinary DR3A running two-speeds. You can see a green resistor used to achieve this.

https://www.flickr.com/gp/90670218@N04/7jD8J3

 

If you want a 120 motor in first class order I have one on eBay at present.

Alan

 

I have a DR2 in my 3A which runs far too fast. Is it possible to fit a resistor to slow it to say half speed permanently? Here in Spain it don´t rain that often so a slow single speed unit would suit me.

Thanks

 

Dave

[AlanT]

A DR2 runs at 35rpm compared to 45 rpm for a DR3A. This is off-load at 12V.

 

If yours runs fast then it may have a fault. The obvious fault is a shorted turn or poor joint on the field coil.

 

These motors can be slowed easily by dropping the supply voltage. The right resistor would do this.

 

You may like to look at this:

http://www.britishcarforum.com/bcf/content.php?156-Lucas-DR3A-Two-Speed-Wiper-motors

 

You have to login to get pictures. Or PM me for the original.

 

I also have rebuilt DR2s.

https://www.flickr.com/gp/90670218@N04/8279c5/

Edited October 28, 2014 by AlanT

[RAHTR4]

Hi Graham,

 

The Lucas wiper motor DR3A 75607B was originally standard fitment on a 1967 Triumph GT6.

 

It appears to be a single speed operation.

 

The wheel inside would have been stamped 140 degree and thus not correct for use on a TR4A.

 

Regards, Richard

[AlanT]

Apart from TR4,4A and 5 the only other vehicle, that used a 120 degree sweep, that I know of is a Sunbeam Alpine.

 

I think the 75568, 120 degree 2-speed is unique to 4A and 5.

 

This is why I have gone to the trouble to make a jig so I can make 120 degree wheels.

 

Most of the DR3As to be found are 75450, 150 degree. There are lots of these from Saloons of the period, of many types.

I can now make these suitable for 4,4A and 5 use and double-speed them as required.

 

Another useful type are B90 reconditioned items. I have a stock of these that have never been used. Mostly these were sold without any gear-wheel.

[Dick]

If the sweep is wrong then reposition the peg on the large wheel at a radius that gives 120degs.

[AlanT]

This is easier to say than do. You must make the peg perpendicular to the thin plate, hold there and then weld or braze perhaps.

 

Oh and you also have to cut the peg loose without messing it up or spoiling the plate.

 

This is why I made this jig:

https://flic.kr/p/nCZKHK

[Dick]

Nice jig......as time goes on it will take more engineering skills and less 'mechanicing' to keep these cars going.

I have a 1933 Talbot......essential tools are a lathe and milling machine.

[AlanT]

And these days a useful small lathe can be had for £200.

 

Actually I bought mine for around £200, but this was 1972.

 

It's kept under a plywood cover and warmed by a 240V light-bulb running on 40V.

This has kept rust off, for over 40 years, in an unheated outbuilding.

 

https://flic.kr/p/oVaYid

 

I used to tell apprentices that I had more tactile pleasure, from using this machine than anything else, except my wife.

[TorontoTim]

If one had a 150 degree wheel fitted, would that just mean that a greater area is swept, at a slightly higher speed, or is there more of an issue than that?

[AlanT]

On a 4/4A/5, with no wear in the parts, the wipers sweep almost the whole screen. With a 150 wheel they would go right off.

 

Of course when you get wear, and it does not take a lot, then the blades slop around and what happens now depends on how wet is the screen. Here they tend to over run even more. In a drier place they probably get held back by friction until the backlash gets taken up.

 

A 6, with the same size screen uses a 115 degree sweep. This is probably a bit easier to adjust and keep them on the screen.

 

I made the jig with three positions 115, 120 and 125, you can see the three holes.

 

I've swapped a few 110 wheels out for guys here because the passengers complained they could not see where they were going!

May also fail vehicle test sometimes.

 

110 wheels are more common here, because of use on Sprites and Minors I think. Please correct if you know better.

 

I have come across the odd brazed-up wheel so this does work, but takes a bit of skill.

I am NBG at brazing, I leave this to hussies.

[TorontoTim]

I'd better check what mine is, then ;-)

[AlanT]

I got into wiper motors because when I refitted the motor that came with the car the arms very nearly did for my brand new paint-job.

 

The PO must have known the value of 2-speed motors and put on a "spare" with a 150 wheel.

 

It took me a while and some research to get to the bottom of the problem. And then a stuggle to get the right thing.

[Don Elliott]

I have the original wiper motor that came with my 1958 TR3A. It's a 2-speed -

SLOW & STOPPED !

[AlanT]

Hope you are still well Don, nice to hear from you!

 

Remember to check the brushes before they bite into the commutator.

[Don Elliott]

Yes thank you Alan. I am very very well.

 

Cheers

 

Don

Edited October 30, 2014 by Don Elliott

[AlanT]

I am pleased to hear it Don. Really pleased, mate.

[Milt]

On 10/29/2014 at 9:43 PM, AlanT said:

This is easier to say than do. You must make the peg perpendicular to the thin plate, hold there and then weld or braze perhaps.

 

Oh and you also have to cut the peg loose without messing it up or spoiling the plate.

 

This is why I made this jig:

https://flic.kr/p/nCZKHK

Hi Alan, I need to move the the peg to give me 150-160 degrees wiper sweep. I currently have a 110 degree gear fitted to my MkIII Midget and the sweep is less than 90 degrees. Would you do me a favour and let me know how far I would need to move the peg? Kind regards Richard

[Milt]

I read the conversation you had a few years ago and it's not for the faint hearted.

I have worked out that I have a maximum of 32mm movement of the cable within the housing, which should give me a 120 degree sweep before the wiper blade hits the lower windscreen rubber. So a measurement of 16mm from the centre of the gear shaft?

I'm planning to use a fine junior hacksaw to carefully remove the peg from the plate. The peg will then be placed in a pedestal drill and turned onto Emery paper to face it (sold my lathe). This should leave a small shoulder from the original.

I'm then going to drill a small hole for the new position 16mm from centre shaft opposite the original position. Drill and tap the peg and attach to the plate with a correct spacer to allow for material lost during removal. Finally weld.

If it goes wrong I'll have to buy a new gear shaft for £70.

 

Edited January 14, 2020 by Milt

[AlanT]

I drill through the plate into the bottom of the pin.  I use a drill ground with a much reduced point so I don't go into the pin very deeply.

The weld is confined to the centre of the pin so not a lot of drilling is needed.  But the weld causes the metal to go hard sometimes.  The older wheels are worse for this.

For a 120 sweep with the standard wheel-boxes you want the centre of the pin offset from the centre of the plate by 12.4mm.

A nice new 120 on eBay at the moment for £38.