Morris Minor Owners Club

Hi All,

I'd better introduce myself first being that I am a newbie to the board! My name is Tristan and (more importantly) I am the proud owner of a 1968 2-door Minor called Agatha - I have put a pic below for your viewing pleasure

Despite owning Agatha for six years now I have to confess that I am shamefully useless when it comes to car mechanics etc. This time, however, I have attempted to make my own diagnosis but would like your advice anyway - I don't fully trust myself

Basically, when I was driving the other night I stopped at some traffic lights and as I released the accelerator the indicator faded out and my radio stopped working. However, when I revved the engine it all came back on! When I got her home I attempted to start her again but she wouldn't - it appeared as though she didn't have any power! This is perplexing as I have only just put a brand new battery into her about a week ago. I'm thinking, therefore, that it must be the alternator but I'm not 100% sure - can any of you guys offer suggestions?

Thanks very much for looking and if I've missed out anything obvious then do ask - I am new to this as you can probably tell!

Tristan<br><br>

Hi Tristan and welcome.
Did the ignition light on the speedo come on at all?
You can check if the battery is charging by using a multimeter to check battery voltage. Get one from Maplins - quite cheap to buy - and they usually come with instructions on how to check basics. Once you have one you will use it for everything

Thanks for the quick reply! The ignition light did come on as did the interior light (albeit very dim). I shall definitely take your advice and get a multimeter!

Thanks again for the advice

If the ign light came on then it's usually a sure indication of a charging fault. Not certain why the interior light would come on though? First check would be that the fan belt is still attached and is tightened up correctly. After that it could be bad connections or a kippered alternator / dynamo.....

Sounds to me that the alternator IS charging - hence radio etc works when engine running - but you have a bad connection at the battery, or at the cables connecting the battery to the car. Check the connections - they must be clean and tight. Is the new battery definitely connected right way round ?

bmcecosse wrote: Is the new battery definitely connected right way round ?

Only applicable if you HAVE an alternator fitted. I know you said alternator but some people call them all alternators when they are in fact dynamo's

I have checked that the fan belt is tight and the battery is definitely connected the right way. Am not sure how to tell the difference between an alternator and dynamo visually - it's a pretty hefty green cylinder shape beneath the coil. I assume it is an alternator?

When we have a proper break in the weather I shall nip-out and check that all the cables are connected right. I had a cursory glance and they all seemed ok...

Thanks for the advice everyone!

Well no - that would be a DYNAMO ! Alternators tend to be squat and silvery coloured! Also - if dynamo, there will be a black control box fitted high up on the firewall in front of the driver - with many wires going to it. Still think it's bad connections at the battery - or perhaps a faulty new battery of course. But - if it was fitted wrong way round - and the dynamo has been charging it 'backwards' - it could well be ruined.<br><br> This is Bull Motif picture of a dynamo - without the drive pulley fitted.

If the charge light has only just come on then the battery would have been OK. The dynamo cannot charge backwards as the action of changing from pos to neg earth or vice versa usually repolarises it automatically. If not you would have to flash the dynamo but the charge light would have been on from the moment the new battery was fitted. If its not had new brushes in the last 6 years it could just well need a new set in.....

Dynamo doesn't always self-polarise, unfortunately. But ML reports that electrical equipment works when engine running - so something is charging! The power is just not getting to the battery - or it's not holding the charge!

Thanks for the info everyone - alot to think about! I am now armed with a multimeter and will venture out at some point this week to see what I can find. Will keep you posted!

An update! I have now replaced the brushes in the dynamo (the old ones were seriously worn out) and, having checked with the multimeter, I think all is working well.

There is now another glitch though, the starting motor doesn't seem to be engaging. I turn the key and it makes a very nice grinding sound but nothing happens. I don't know what you guys think, but I am hoping this may be due to the battery being flattened after all its exertion. So I am going to charge it up and see.

Yes - it could be completely flat battery - but if it won't start, how do you know "all is working well" ? If you have bump (or handle) started it - it would charge up the battery sufficiently in a very few minutes. Check again all battery connections!

Battery has been charged and reconnected and she started the first time! Have tried again today just to make sure and is going like normal again. Thanks for all your help everyone

So - is the Ign light now working as expected? You should check the battery volts with engine running at a good fast idle - should be 13.8/14 volts. This confirms it IS charging!

you know a voltage or ampere gauge hooked up to the car will till you instantly when were the problems are sometime.

Like in your case the electronics worked fine in the higher RPM range which would indicate worn Brushes (or bad diodes in alterantor) however when this happened a simple look at the gauge would have told you exactly what was happening it would have been very low when at idle and then spiked when reved up.

I am a big on auxliary gauges over dummy lights (what we call them in the U.S. the little lights that come on when somthing is wrong)

All of my cars have a Oil pressure Voltage and temp gauge its the first thing I do to every car get that doenst have them

The ignition light is working as expected. Have checked all with the multimeter and have driven her a couple of times since. Everything is back to normal