TR4A/TR6 wiper motor conversion - looking for the correct dash switch to use

[Tr4aJim]

Folks, I’m going to do the TR4A/TR6 wiper motor conversion this winter. I’ve been reading many of the posts here regarding this conversion, and I think I understand all the items needed like swapping in a 90 degree drive gear. I plan on using the 4A wheel boxes and drive cable. However I’m a bit confused on what switch to use with this motor. I want to use a switch that hopefully will fit in the 4A plinth. I found this switch on the SVC site. Will this work? Are there better choices?

thanks

Jim

 

[RobH]

The switch required for the TR6 wiper is a bit special. 

The switch needs to have four connection pins with the sequence:

position 1 - -----pin1 > pin 2

position 2 ------pin 2 > pin 3

position 3 ------pin3 > pin 4

Unless the switch you show does that, it won't work.  Most switches available are not arranged that way. The 'correct' switch available  is a rocker type  - Lucas 39748A

If the rotary switch sequence is 1>2, 1>3, 1>4 It is possible to make it work with the addition of a relay.  

You would connect 12V to pin 1,   pin 3 to motor pin 5,   pin 4 to motor pin 3.     Switch pin 2 is used to operate the relay which connects motor pin 2 to motor pin 5 to park the wipers.    I will post a drawing later.

(Later):

 

 

 

Edited November 29, 2023 by RobH

[Chris Hubball]

Our resident wiper expert Roger H should be along soon to help.

Cheers Chris

[Tr4aJim]

Thanks Rob!  I found this switch on Moss listed for a TR6, and it includes connections for a power washer too. Might that work?

I’ll be interested in what Roger says. I did read his description of modifying a stock 4A switch, but it sounded like it required a higher skill level than I have (after all, electrical stuff is basically magic, right?).

Jim

[RobH]

Yes that Moss one is correct. They have even included a wiring diagram :

https://www.moss-europe.co.uk/media/pdf/155496_instructions.pdf

[BlueTR3A-5EKT]

Have you read the MGA Guru article on fitting the round bodied two speed wiper motor in place of the old square bodied unit?    This is US based so might yield some parts sources closer to home for you.   The switch being replaced is like a TR one.

http://www.mgaguru.com/mgtech/electric/et218.htm

In truth Roger H does a splendid conversion to the original TR switch so it works on TR 6 wiper motors.  You retain the original push pull operation and knob.

He’ll be along in a moment……

 

 

To go on my TR3 I have gone the Land Rover Ser3 switch which has a two speed motor and an electric wash all in the same switch.    Ungodly expensive switch to buy though.   Land Rover part number 575146

 

 

Edited November 29, 2023 by BlueTR3A-5EKT

[RogerH]

Hi Jim,

You can modify the existing TR4A two pull knob/Switch.

It is not difficult but needs a spare contact.

Pull the knob out to the first click.  This will position the innards in  a happy place.

Unlock the four pinch grips that hold the metal to the bakelite - they pull out quite easily.

Pull the metal work OFF the body.  DO NOT fiddle with this - place an the bench and leave it alone

Look inside the body and note the contact at position 8.  You need to duplicate this contact at position 2.  This is the park position.

The hole in the contact is 3/32".  I use a 1/8" pop rivet with a small washer for the tail to react to.  Be careful the bakelite is brittle and can break easily.

To re-assemble you need to make a small strip of metal  2" x 1/4"  x 0.048" This slides in through the back of the switch to hold the metalwork contacts apart

You can now push the metal work up the metal strip, into the body and press closed.  Re Grip the four locks.

The wiring is simple

Position 2    Green / Brown  Park

Position 4 Green                  Power 12v

Position 6 Green / Red        Normal speed

Position 8  Green / Blue     Fast speed.

I'll send you a PM

 

Roger

 

PS - new TR4A switch are available and not too expensive - it may be worth buying a new switch and use your switch as a basis for spare contacts

or vice versa.

 

Roger

 

Edited November 29, 2023 by RogerH

[Tr4aJim]

Thanks Rob & Peter!

Roger, I’m guessing your description will be easier for me to understand when I’m actually looking at the switch.

So the plus for modifying the 4A switch is no mods to the plinth are required, as I believe the TR6 switch is wider.

Just to confirm, the Green 12 volt wire you mention, is the existing 4A green wire to the stock wiper motor? If so, will the TR6 motor work okay with the stock 4A fuse (as the heater blower motor shares that fuse)?

Jim

[RogerH]

Hi Jim,

any Green wire should be +12v..

There is a mini loom that is required to join the motor to the 4A

 

Item #95  https://www.moss-europe.co.uk/shop-by-model/triumph/tr5-6/electrical-system/wipers-washers/windscreen-wiper-system-tr5-6-1967-76.html

 

Roger

[Andy Moltu]

There is another way to do the switch.

Take apart the existing switch as per Rogers instructions, and do the same with a classic Mini 2 speed toggle switch and put the back of the Mini wiper switch onto the front of the the TR switch. In spite of one being a toggle and the other a pull switch their internals mate perfectly. A lot cheaper than the later TR6 switch which like the Land Rover switch is very expensive but does combine the washers with it if that's what you want.

I took some pictures when I did mine based on the work Roger had already done and put the article in TRipe - the Leicestershire Group newsletter which I've attached.

TR4A wiper conversion.pdf

[Tr4aJim]

Thanks Andy!

Jim

[Rob Salisbury]

Just asking the question, what are the advantages of the TR6 wiper motor over a fully functional 4A two speed version?                                                                                      Cheers Rob

[RobH]

The DR3a motor is weak Rob. The method of getting the fast speed is a technical bodge which also reduces the motor torque. The TR6 motor is much better. 

[Rob Salisbury]

Thanks for that Rob, though I think my one has been fed on Weetabix or Spinach 'cause it throws the blades around with great enthusiasm on both speeds and the whole switching regime is so much better having followed your correct wiring scheme .... (closed on fast when I first got the car in 1969 so I think it was always like that)                                         Cheers Rob  

[Tr4aJim]

Of course swapping motors is only the first step to getting a more efficient wiper system. Then I’ll start looking for replacement wiper arms/blades to replace the weedy stock ones. Hoping SVC will be a good source there.

Jim

[Andy Moltu]

The 14w motor is cheap, reliable, readily available and more powerful with more torque than the one on the 4.

If you use the 90 degree wheel you don't need the TR6 wiper boxes. The rack is the same. The 4 arms are slimmer and the blades are slimmer to fit and slightly shorter than the TR6 items. Why is puzzling as the screen the same and the longer arms don't manage to contact the curved part of the screen?

[Tr4aJim]

The issues I have with the stock 4A wiper arms/blades (at least the ones on my car), is that the arms barely grab onto the knurled shafts, and the arm “bayonet” attachment socket on the blade is so flimsy the arm rocks back and forth when the wipers change direction. We were caught in a heavy thunderstorm last summer and the wiper performance was so ludicrous, we were laughing out loud (when we weren’t gasping in terror).

Jim

[RogerH]

The DR3/DR3A motor is so poor it would have trrouble with bigger wipers.

 

Roger

[RogerH]

Hi JIm,

I use the TEX arms that have a screw wedge that attaches the arm very positively indeed.  TRGB in the UK do these arms.

This style  HERE  but I do not know the part number

The blade needs a certain amount of flex at its joint to allow it to flip flop. Otherwise it will judder across the screen.

Of course with the 14W motor you could use the TR6 blades.

Roger

Edited November 30, 2023 by RogerH

[Andy Moltu]

The screw on arms lack anything to retain them onto the wheel box bar the grip of the screw force. Mine worked off. 

Have reverted to tex clip ones.

[RogerH]

Hi Andy,

 the screw forces a light metal wedge between the wheelbox spindle and the arm casing (both of which are splined

I'm sure they could part company but do give a good grip in the meantime.

 

Roger

[Andy Moltu]

Rotational grip is fine but mine worked off so have reverted to clip on ones.

[RogerH]

Hi Andy,

I must declare that in the last year I have had both the right and then left wiper arm come off.

I put it down to me not tightening the screw (Gorilla) tight.

So far both arms remained on the bonnet.

I think I shall connect them with a lovely pink ribbon - just in case.

 

Roger

[BlueTR3A-5EKT]

1 minute ago, RogerH said:

Hi Andy,

I must declare that in the last year I have had both the right and then left wiper arm come off.

I put it down to me not tightening the screw (Gorilla) tight.

So far both arms remained on the bonnet.

I think I shall connect them with a lovely pink ribbon - just in case.

 

Roger

Wire locking would be my solution 

[RogerH]

Hi Pete,

 could be difficult and look tatty

 

Roger