Alternators, belts, jiggery pokery

So I've fixed the battery problem and I'm starting properly again. I did notice some squeal from the alternator belt the day before the battery failed but it's been fine with the new battery. Questions...

Does the alternator give more resistance to the belt when the battery is knackered/low?

The belt (less than six months old) does seem as if it could do with a little more tension. Simple a case of removing the filter box, intercooler hoses, slackening some bolts, jiggling the alternator and reversing the procedure? Anything to watch out for?

I've a spare belt if/when that becomes necessary. Is there a good reason why the alternator belt was placed behind the power steering belt? I read somewhere that the job is easier without the fan and cowling in the way, although my haynes manual seems to insist that that step also requires removing the radiator. Is that actually the case?

Ta in advance..

pishmishy said:

So I've fixed the battery problem and I'm starting properly again. I did notice some squeal from the alternator belt the day before the battery failed but it's been fine with the new battery. Questions...

Does the alternator give more resistance to the belt when the battery is knackered/low? No.

The belt (less than six months old) does seem as if it could do with a little more tension. Simple a case of removing the filter box, intercooler hoses, slackening some bolts, jiggling the alternator and reversing the procedure? Yes Anything to watch out for? The skin on yer knuckles.

I've a spare belt if/when that becomes necessary. Is there a good reason why the alternator belt was placed behind the power steering belt? No I read somewhere that the job is easier without the fan and cowling in the way, True although my haynes manual seems to insist that that step also requires removing the radiator. Is that actually the case? No - complete bollox.

Ta in advance..

Click to expand...

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Thanks. I didn't think that removing the radiator made sense =) And in this case the workshop manual was a lot clearer.

So they were just being awkward placing the belts in that order? Grrr ;-)

Ere, Trewey, if the battery was knackered it would draw more power wouldn't it and therefore the alternator would put up a bigger resistance so it would be more likely to slip....wouldn't it???

pishmishy said:

So I've fixed the battery problem and I'm starting properly again. I did notice some squeal from the alternator belt the day before the battery failed but it's been fine with the new battery. Questions...

Does the alternator give more resistance to the belt when the battery is knackered/low?

The belt (less than six months old) does seem as if it could do with a little more tension. Simple a case of removing the filter box, intercooler hoses, slackening some bolts, jiggling the alternator and reversing the procedure? Anything to watch out for?

I've a spare belt if/when that becomes necessary. Is there a good reason why the alternator belt was placed behind the power steering belt? I read somewhere that the job is easier without the fan and cowling in the way, although my haynes manual seems to insist that that step also requires removing the radiator. Is that actually the case?

Ta in advance..

Click to expand...

Yes the more power the alt is producing the more energy it requires to make this happen, a powerful alt charging at full load will require a few horsepower in order to work, if the belt is incorrectly tensioned it can squeal or even snap if it's in bad shape.

Knackered battery = little charge = alt will have to charge at a higher rate to keep up with all the electrics and to try and bring the battery up to 14/14.5V.

When you start an engine on a summers day, the alternator will (once spinning fast enough - often not idle) start to recharge the battery, once this has happened the alternator will generate just enough to keep the battery topped up and run the basic ignition electrics - this usually takes about 10/15minutes at a fairly high output (all it wants is to lift the voltage back up), so if it's doing this all the time on a knackered battery you can see why they give up the ghost.

A bad battery will increase fuel consumption and if left for too long will lead to the alternator packing in (usually the diode pack fails - these can be replaced).

Thanks that's starting to make sense, and fits with the symptoms I was seeing before it died. I'll see if I can tension the belt a little at the weekend, but otherwise I'm not as worried as I was =)

Since I've learnt too much about how batteries work, I may at some point go and teach myself a little about these alternators now!

I sheered the thread off the tensioning bolt on the bottom of the alternator, and now i cant get it off to get a decent bolt on, grinder doesent fit down there eather. Im complitly boned.

So dont over tighten those things, even though its very tempting!

woods767 said:

I sheered the thread off the tensioning bolt on the bottom of the alternator, and now i cant get it off to get a decent bolt on, grinder doesent fit down there eather. Im complitly boned.

So dont over tighten those things, even though its very tempting!

Click to expand...

It's a good job that I'm a bit of a wimp then! Is it easier to work these bolts from above or below? Can you not get a smaller grinder in there?

I only have a small grinder! Loks like ill be pulling all the belts off so i can get at it. Seems to be working for now, just. Very loose belt, being held by fricton on the top piviot bolt.

What have you got to work with? Is the bolt/nut just spinning?

Yea, wont come back off the thread is mullered.