Ignition light glowing

[Essex Stag]

Took the Stag for 30 mile run today when I noticed the ignition light glowing at about half brightness . I revved the engine it did not change the glow of the light at all . I turned into a junction looked again it had gone out any ideas why is the alternator on its way out ? or could it be something else . Also you nearly lost me and the Stag today when some idiot parked in a lay by decided to do a U turn across the front of me how I missed him I do not know thank god the brakes are good on the Stag all I saw was a black car broadside about 20 feet in front of me . If I had been in my Rover P4 I would have bent him in half as she ploughed though him like an ice breaker she has brakes but not as we know them captain
Derek.

[Danny]

Aye Derek,

I sounds like the alternator is on it's way out.

[Essex Stag]

Thanks Danny I will get it checked out . there is no sign of it not charging the battery as she turns over very fast when cold starting so I was wondering if it was just a bad connection somewhere but thanks for he reply
Derek

[SaskStag]

Loose belt? That's what happened to me, well actually the alternator fell off its mounting......
Tanya

[Essex Stag]

Thanks Tanya come to think of it I did hear a little screech from the fan belt the other day you just reminded me I will check the tension. Don't want any of my bits falling off
Derek

[Essex Stag]

Took the Stag out again today the ignition light keeps coming on randomly when it's on the voltmeter shows 12 volts as soon as it goes off it reads 13.5 volt . I also notice when starting away it showed 11 volt then gradually rose to 12 volt . would this just be a loose drive belt ?
My alternator belt is a toothed belt is that correct as the power steering belt is the traditional vee pulley belt is this correct


Derek

[wilf]

Worth checking all connections including earths before condemning the alternator.

[peterl]

Once you have checked the belt tension and the problem still persists, and the ignition warning light intermittently glows and becomes progressively worse over the next week or two, the alternator brushes are usually too short and need replacing.
Peter

[Mike Stevens]

Agreed it could be the brushes, but in my experience although the light glow dimly at low revs, it goes out at higher ones. Certainly worth checking though.

Cheers,
Mike.

[staggering]

Derek,
If I remember correctly, sometime ago I had similar symptons and found that cleaning each of the fuses and carriers in the fuse box (engine bay) cured the low rev ign glow - maybe worth a check before Alt replacement etc, good luck.

cheers
ian

[Essex Stag]

My ignition light does not glow at low revs it is a constant brightness almost the illumination you get at first switch of the ignition it does not glow dimly or at low revs it glows at the same brightness what ever the engine revs are even reving very high does not change it then suddenly it goes out and the volts increase.
Oh the joy of old cars as soon as I can I will check the belt tension
Thanks Derek

[73stagman]

When the alternator light is on the alternator is not charging so the voltmeter will show a drop in volts and vice versa.
Check for slipping belt (Unlikely it would be squealing its head off) or slipping pulley if the nut has come loose or the key has sheared on the alternator shaft.. occasionally picking up and the alternator then gets working.... Then if that's the case you need to find out why which is most likely a damaged / worn bearing in the alternator
If none of the above then the alternator is faulty inside!
Any of the above will require the alternator and / or pulley and / or belt to be replaced

[Essex Stag]

Called to see an auto electrician I know today and told him the symptoms I am having and he instantly said its the Alternator on its way out. the belt must be broken or slipping and screeching to cause the light to glow at full intensity. He will rebuild it for me but he asked me does it have its own inbuilt voltage rectifier or is it separate before I take it to him or I will have to run it over to him to let him have a look . Well whats the answer it is a Mk 2 , 1977 model it was auto but now manual.
Derek

[staggering]

Called to see an auto electrician I know today and told him the symptoms I am having and he instantly said its the Alternator on its way out. the belt must be broken or slipping and screeching to cause the light to glow at full intensity. He will rebuild it for me but he asked me does it have its own inbuilt voltage rectifier or is it separate before I take it to him or I will have to run it over to him to let him have a look . Well whats the answer it is a Mk 2 , 1977 model it was auto but now manual.
Derek

Derek,
This guy knows his stuff - my 76 should have had an "inbuilt" regulator, i.e. within the alternator, but it had the "external regulator" type which is indicated by a small black box - the regulator - normally housed just under the wing top edge in the engine bay (offside) and has several wires connected to it - these are usual for MK1 cars - so I was surprised to find it on mine. I converted to the "proper" Mk11 (internal regulator in alternator type) some years ago but can't remember the process
Apologies if I have over complicated the answer, others maybe able to explain it better - if it is driveable it maybe better to take it to him before he gets the relevant bits asits no immediately obvious - good luck

Cheers
Ian

[Essex Stag]

Thanks Ian
Yes this guy knows his stuff I have known him for over 35 years. Since posting I have looked at the price of a recon one and they start at about £ 40 plus vat and of course delivery not bad if it comes to to less than £75 . I will ring him tomorrow to see what he charges to take it off and refurb it . . The good thing about using him he will check everything else is OK as well
Thanks for all your help lads
Derek