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MG TD TF 1500 - Wiper wheel box TF

My wiper wheel boxes still work but recent problems (now sorted) showed that the gear wheel teeth are well worn and only engage with the cable rack because I have fitted a very thin shim in the cable guide within the wheel box which forces the cable to engage with the worn teeth but without adding too much pressure. Wheel boxes are difficult to find in the UK from the traders and are usually just as worn anyway.

Has anyone found a source of decent quality gears, or alternatively, sourced a supply - possibly from a 3D printer? If all else fails, and if I can find a cheap second hand gear wheel from which to make a correct scan of the teeth profile, and there is sufficient demand, I am thinking of commissioning a 3D printer supplier to make a few.

Any thoughts?

Neil.
N D Wallace

The gears tend to wear on only a section of the circumference. A work around fix is to remove the cable and reset the wheelboxes to work on another section of the gear.
John Quilter (TD8986)

Neil,
I doubt if that is going to work. 3D printing is only affordable with plastics. 3D printing in metal is very expensive. You would be better off having them CNC cut. You need to measure up the gears and do some reverse engineering. The speedo replacement gears that I had commissioned were made in brass.

Regards
Declan

Declan Burns

Declan - I haven't looked inside my wiper gearbox in years, but as I recall, the small gears are metal. You can find a good selection on AliExpress. Just enter "small metal gears".

I'm lucky. I have a nearly-new spare wiper gear drive, But I rarely use my wipers. I've found Rainex to be so effective.

Gord Clark
Rockburn, Qué.
Gord Clark

Declan, thanks for your valuable comments; perhaps CNC is the way to go or, looking at other comments, try to source the correct diameter and "tooth count" gears. As the car is 68 years old, the teeth on the current gears are badly worn all round - clearly John Q's suggestion has been used many times already!
N D Wallace

We need to clarify here, are we talking the gears inside the wiper motor or the gear in the wiper wheel box that is under the wiper arm and is driven by the cable? Declan's photo shows the motor gear on the right side of the photo.
John Quilter (TD8986)

John, I’m referring to the wheel box behind the dashboard. In the UK the refurbished wiper motors are readily available, but the wheel boxes are virtually unobtainable.
N D Wallace

N D Wallace, I am surprised there is not greater interchangeability with other cars with the wheelboxes which I assume are a Lucas item.
John Quilter (TD8986)

ND,
Do you have a photo of the wheelbox in question?
Regards
Declan
Declan Burns

ND, have you looked at the Lucas Overseas Technical Correspondence Course #8 - Windshield Wipers etc - see https://www.mg-cars.org.uk/imgytr/pdf/lucascourse8.pdf

You may also like to read this article discussing wiper motor repair by Mike McPhail and reprinted from Moss Motoring https://www.mg-cars.org.uk/imgytr/hints&tips/wipermotorrepair.pdf

Stuart
Stuart Duncan

Stuart, thanks for the Lucas technical note.

The arrangement on my car (TF1500) is as per 3rd diagram on page 7, being of the Lucas CR design. My query relates to the wiper wheel boxes, one in each glove box in the dashboard, and not the motor itself. Each wheel box has a gear, controlled by a knob that engages or disengages with a "twist and push" movement. This allows each wiper blade to be brought into engagement with the cable rack or parked, but only the wheel box on the drivers side supplies power to the motor located in the engine bay on the fire wall.
The gears themselves within each wheel box are permanently pinned to the operating spindle between operating knob and wiper blade the other side of the windscreen.
In answer to another question, it had occurred to me that the Lucas system might be found on other British cars of the period, but the Lucas technical note suggests there were quite a few variations on the basic design and so far I have not come across another car make & model with the same wheel boxes as mine. Either way, only well worn examples are offered at trade stands in shows, but rarely, and priced in really silly money for items that are as badly worn as mine! If they were a lot cheaper I would buy one in order to dismantle it and see how it actually works in terms of how the gear moves in and out of engagement with the cable rack, and if the is some kind of clutch or spring arrangement within the gear wheel hub.

Declan, and others.

Here is the passenger side wheel box with the cover slid down the shaft. The operating knob would normally be on the end of the shaft - you can see the screw hole for the knob screw. The electric wire is not part of the wiper set-up. The shaft passes through the scuttle to the wiper blade on the other side of the windscreen.

Neil.


N D Wallace

Neil,
It appears to be a worm gear but difficult to see the tooth profile.
Regards
Declan
Declan Burns

Declan,
It is a flexidrive cable rack and pinion. I think this sweep angle was only used on the TF Y type and RM Riley.
Ray TF 2884
Ray Lee

I found this which is quite a good explaination.
https://morganrebuild.co.uk/WindscreenWiperMotor.html
SVC have quite a selection of Lucas wheelboxes.
https://www.s-v-c.co.uk/categories/stafford-vehicle-components-washer-wiper-systems-wiper-system-components
Regards
Declan
Declan Burns

The SVC wheel boxes are completely different being, I think, because they are not a alloy casting. They do, however, achieve the same purpose which is to transfer a reciprocating cable into a rotary action of between 80 and about 120 degrees of sweep arc of the wiper blades. They would not easily replace the originals. I do not know the teeth profile because they are badly worn on my car - and all the secondhand ones I have seen for sale by traders - but I guess that once removed from the wheel boxes and compared with the comparatively unworn cable drive the profile could be worked out.

My mission is to find either suitable substitute gear wheels or a secondhand wheel box that I can dismantle for detailed inspection.

Neil.
N D Wallace

This thread was discussed between 27/08/2022 and 04/09/2022

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