Wiper motor

[Jessica Herald1961]

Is it possible to fix a wiper motor?

 

Does anyone have one lying around? (Happy to pay!)

 

How do I check if it's actually the wiper motor that's stopped working? 

[PeteStupps]

Hello,

What happened? Did the wipers just stop moving? Have you checked you're getting 12V to the motor when the switch is on?

I'm not an expert but did some work on mine this year. I found that if either of the wheel boxes were jammed (as mine was) the motor didn't have enough torque to move anything. However the motor didn't burn out, which I expected it would have. 

There are also carbon brushes in the motor, which may have worn out or lost enough spring tension to hold them against the commutator. When I dismantled my motor, the tiny spring fell out and was lost, so beware of that if you do take it apart.

See item 4 on the Canley diagram here:

[Jessica Herald1961]

Thank you. Turns out all I needed to do was screw the switch back onto the dashboard!

[RobPearce]

Ha! Well, I'm glad it was a simple fix.

If you ever do need to refurbish the wiper motor, it's not at all a bad job. I did my Spitfire's one last year. The self-parking is the only awkward bit - both the wire that goes through a hole so it needs to be unsoldered for dismantling, and the little rivets that are supposed to make the electrical connection through the cover but have usually rotted away.

One thing Pete's post might mislead on - you should have 12V to the motor whenever the ignition is on - the wiper switch is on the earth side on a Herald or early Spitfire.

[RustyRick]

It’s a worthwhile project. After 40-50 years the grease goes hard in the wiper gearbox and the drive cable tube. They work much better after a clean and re-grease.

 Rick 

[PeteStupps]

Quoted from RobPearce-

One thing Pete's post might mislead on - you should have 12V to the motor whenever the ignition is on - the wiper switch is on the earth side on a Herald or early Spitfire.

I was not aware of that, thanks. A little knowledge is a dangerous thing, as they say!

[Bitumen Boy]

Quoted from RobPearce-

If you ever do need to refurbish the wiper motor, it's not at all a bad job. I did my Spitfire's one last year. The self-parking is the only awkward bit - both the wire that goes through a hole so it needs to be unsoldered for dismantling, and the little rivets that are supposed to make the electrical connection through the cover but have usually rotted away.

 

The one I did didn't have a wire needing to be unsoldered, so it's not all of them - just a matter of luck which type you have!  Adjusting the self-parking is the bit I found awkward, I eventually settled for "near enough". Things are no better with modern cars, I had to replace the wiper motor on my Corsa last winter and also ended up settling for "good enough" rather than dismantle it all again to make an adjustment... 🤔

[Hogie]

Hi Folks,

          these dodgy motors turn up like buses.

My 2 speed DR3 on the TR4A died on the Isle of Lewis. I used my boot laces to operate the disconnected wiper blades - deep joy (but easy to do).

The two copper rivets on the lid for the self parking MUST be insulated from the lid.

Quite often the high speed winding insulation disintegrates and shorts out.

This is not a conventional winding but a resistance wire wound on the field coil.

Easy enough to remove and clean and refit without shorting - coated mine with RTV silcon sealant.

I eventually fitted the TR6 14W motor - cheap, and plentiful.

You need to get the correct gear wheel for the sweep. However the wheelbox gear will affect this.

On my 4A I left the 4A wheelboxes in place and fitted a 90 degree gearwheel in the motor.

This gives almost 120 degree bade sweep.  AND it works wonderfully.

 

Roger