Intermittent fault - wiper motor

[AlanT]

Everyone knows that faults which are intermittent are the hardest to find.

 

This motor would run for ages and then just refuse to start. After a while it would go again.

 

Eventually the owner got desperate and sent it to me. It seemed fine at first. I gave it my usual clean, lubricate and service.

 

Then it just stopped. I popped in a spare armature and off it went.

 

My standard armature test soon showed an open-circuit but on close inspection this proved an easy fix.

 

Over 50 years ago the production operator failed to solder this joint. This thing has survived all this time just because the wires were touching for most of the time. Amazing.

 

Edited April 28, 2016 by AlanT

[John Morrison]

Yes amazing Alan,

 

and congratulations on finding something so obscure.

 

John.

[John Bracher]

That looks to me like a manufacturing defect!

Warranty claim, I say!!

[Don H.]

For all the criticism of Lucas -- and over here lots of people with no first hand experience with the brand love to tell bad jokes about Joe & co. -- their stuff is usually very serviceable and repairable. I find it seriously impressive that one can take apart a 50+ year old electrical bit, service it (sometimes with NOS parts) and put it back in operation. Almost all the parts that were put on my car in April 1962 are still on it.

 

Well done to salvage an old armature!

[AlanT]

I've been fault finding electrickery for 50 years plus. I've a sixth-sense about it.

This was found in under ten minutes. It took longer to get the wires to tin.

 

The quality of the parts in these motors is amazing. I just compared the diameter of an NOS gear shaft and crankpin with one that has been in use for many years. Less than 1 thou difference. Hardened steel in Bronze.

[stuart]

I seem to have spent a lifetime arguing with lots of our colonial friends over the merits of Lucas parts, they have always bad mouthed them as being unreliable or poor quality which couldnt be further from the truth. Try Italian stuff!

Stuart.

[Don H.]

I seem to have spent a lifetime arguing with lots of our colonial friends over the merits of Lucas parts, they have always bad mouthed them as being unreliable or poor quality which couldnt be further from the truth. Try Italian stuff!

Stuart.

 

Agreed, Stuart. It's a convenient joke, usually made from complete ignorance of the quality Lucas built into their parts. I've spent a lifetime defending Lucas to my countrymen. Dumbasses who don't know how to make a ground connection, and laugh as they blame someone else.

[AlanT]

Whilst the quality of material and manufacture is good, maybe even excellent, there are often design weaknesses.

 

One reason for this is that design details were often left to "draughtsmen" rather than being thought out by mechanical engineers.

Often these blokes did not consider ease of manufacture. The TR pedal box is a great example of this.

 

With the wiper motors you find it takes a lot of skill to do the soldering. There is nowhere to put the wires.

Many draughtsmen argued with me saying "we don't draw wires.

 

[ianc]

A great many of the electrical faults in earlier times were the caused by bad earths, because the bodywork, which provided the earth return path, rusted and disintegrated. The answer, of course, is to provide a return path in copper cable from each device: lamp assembly, wiper motor etc.

Ian Cornish