18 replies to this topic

[xchickyx]

Model:Cooper 1.3i
Year: 1996 - fan on the right, snug next to the alternator.


Hey all, this is driving me absolutely nuts!

Today is the ONLY chance i'm going to have to fix this for a long time, but i need to be able to drive the car. So ANY help is appreciated!

I have searched the forum, replaced my drive belt 3 weeks ago and spent the last two hours to get the 13mm slack perfect (re-adjusted it today). But i still have this DAMN SQUEALING, ONLY when the LIGHTS are on.

It's driving me mad, i'm guessing it's the alternator that's causing the problem; when the lights are on it has to put more stress on the belt?

I dunno but i need to fix this NOW as i have a very important date to make tonight and don't fancy my car screaming at everyone the whole journey.

Oh and for the record, i have ZERO noise when the lights are off.

Please help!

[Guess-Works.com]

Where are you testing the slack ?

and is that 1/2" up and down or 1" total ?

Slack should be tested between the alternator and bottom pulley (the longest run of the belt between pulleys), not between the alternator and water pump as many people assume...

Edited by GuessWorks.co.uk, 17 December 2009 - 01:29 PM.

[xchickyx]

Yeah i tested it on the bottom, like the haynes says. It's about 1cm up and 1cm down, is that wrong?

Edited by xchickyx, 17 December 2009 - 01:32 PM.

[Guess-Works.com]

it should be 1/2" in total, or 13mm in new money....

[GraemeC]

Try sprinkling the belt with a little water whilst it is squeeling. If it stops the noise then it is probably the belt that is the problem, if it carries on then it is probably the alternator bearings

[xchickyx]

I will tighten it a bit more and try Graeme's idea, i'll post back in 10 minutes

[Dan]

It is too slack so that's probably the problem but when you changed the belt did you clean the pulleys?

[xchickyx]

Didn't clean the pulleys no, i'm a bit of a noob when it comes to mechanics.

[xchickyx]

Right well i have now discovered a forth bolt, which is the REAL adjustment bolt. I loosened the wrong one (thus limiting how much the alternator can be moved).

But f''ck me this bolt WILL NOT SHIFT. I have managed to get the bolt to the point where it can wiggle a little but i can't get it unscrewed any further, my spanners keep slipping!

Does anyone have any tips for this *illegitimate person* of a bolt? It's the one right at the back of the alternator, where no human can possible see or get the hand into I don't know how they expect you to adjust the alternator when the main adjustment bolt is in such a bloody stupid place.

...and now i've successfully wasted the majority of my day, i started at 10am and now its 3pm and i have nothing to show for it. Just another thing to bring me down this week, brilliant!

[xchickyx]

And to add to it all, my hands wont stop bleeding.

[pantera2075]

There are 4 bolts/nuts. 3x 1/2" spanner, 1x 9/16" spanner

You only need to slacken them a bit - just enough to allow movement, a bit of "drag" is good.

Then, get a lever - I usually use a wooden handle of a hammer behind the alternator and lever it away from the block until the belt is tight.

keep some pressure on the lever and tighten the 9/16 nut.

Tighten the rest.

If this still squeals, then either yr alt/water pump bearings are shot, or the alternator has the wrong pulley or it's out of line.

I know the above is a bit Heath Robinson, but it's worked literally hundreds of times for me with no probs.

[GraemeC]

Firstly, make sure you have the right size spanner - 9/16" AF (if it is still the original fixing). However chances are you have rounded it off now.

Presuambly you have removed the grill to give better access?

Personally I would now take the time to remove the alternator (you don't need to undo that bolt to do so) and then get everything freed up and moving whislt you have more access.

The bit you are looking to loosen should look like this (for reference):

[chrisxr2]

another one for removing the grille, first time i adjusted mine i adjusted the wrong nut and did'nt take the grille off. Grille off job easy and saw where i had gone wrong the first time.

[[email protected]]

Before anyone says anything, I realize this post is from 2009 and the OP has likely solved his issue....

 

But I am pointing to another link as another resource for the NEXT chap who comes along and says "Mine also makes noise only when the lights are on - I don't understand why!"

 

See http://www.myminipro...c-mini-faq.html for this text:

 

To test if the fan belt is tight enough, turn on the engine, the headlights, hazard warning lights, radio, wipers and any other electrics that will place a load on the alternator. If the fan belt makes a squealing noise then it is slipping.  So turn the electrics and engine off, loosen the alternator bolts and lift it higher so the fan belt is tighter with hardly any play. I prefer to slide a long socket set extension bar under the alternator and rest it against the engine block so I can use the bar to lift up the alternator body with one hand and use the other to tighten the three alternator bolts. I then press down on the top of the fan belt between the alternator and water pump with one finger and if there is more than a little play I will raise the alternator a little higher. The real test is that the fan belt should not slip (a high-pitched squealing noise) when under heavy load (slow speed or idling with lots of electrical components switched on).

[KernowCooper]

If you pull the belt up and eliminate the 1/2inch of slack on the longest side to stop the belt squealing under load, you risk pulling the water pump baring out, or the alternator. If you need to tension the belt tighter than the recommended 1/2 inch of free play, then the belts worn and most likely could be bottoming out. Time for a new belt and ensure its correctly aligned.