Alternator questions / problems

jj · Post by jj » Fri Dec 28, 2007 6:06 pm

Been using the car daily last few weeks, and noticed last week it started "chirping" when at low revs. This got worse, then started to belt squeal, so decided to get the wheel off and have a look at the alternator.

Technical terms coming

- the top "pivot" bolt had lost the nut and was halfway out, making the alternator sit squint. I am guessing this is the cause of the squeal. The bottom "tensioner" arm bolt (the one nearest the back of the car) had also worked itself loose, but I cant see how to undo the little screw that goes into the alternator and stops the "arm" moving past the set point? Will it be OK to use this belt again (it looks spotless as it and the alternator are only 5 months old). There was a lot of copperslip on every bolt which may have aided the vibrating free process?

I hope that makes sense, its all in bits at the moment and re-assembly is tomorrows hungover task. Ta in advance chaps.

Post by **Shug** » Fri Dec 28, 2007 6:16 pm

Not expensive to replace IIRC, but I'd not imagine any damage if it's not scored or cracking.

I'd chance it, as it's not gonna kill the engine if it goes - just strand you somewhere the locals might think you purty....

BiggestNizzy · Post by **BiggestNizzy** » Fri Dec 28, 2007 6:16 pm

probably be ok (in no way taking responsability if it goes t1ts up) but how much is a new belt ? me being a pikey tight 4rse would bung it all back on. but then again I have not seen it

jj · Post by jj » Fri Dec 28, 2007 6:46 pm

It looks brand new so i`ll put it back together and see what happens. The alternator doesnt make any noises or have any play in it so I hop the few days of running with a squinty belt hasnt gubbed it.

Access is a slutbag isnt it

?

robin · Post by **robin** » Fri Dec 28, 2007 9:22 pm

The little screw that tensions the arm is an 8mm head - it points more-or-less into the driver's back, so the spanner goes between bulkhead and alternator - best if you have a wee ratchet spanner as not much else will fit - lean down from the top.

The top pivot bolt being loose means it will have received some impact, ditto the bottom bolt (near the crank pulley). The bottom bolt is notorious for shearing and is a royal PITA to remove the left over bolt from the block without removing the engine. I would replace both bolts ASAP (I have had two of the bottom bolts fail on me).

Cheers,
Robin

jj · Post by jj » Sat Dec 29, 2007 6:03 am

robin wrote:The little screw that tensions the arm is an 8mm head - it points more-or-less into the driver's back, so the spanner goes between bulkhead and alternator - best if you have a wee ratchet spanner as not much else will fit - lean down from the top.

The top pivot bolt being loose means it will have received some impact, ditto the bottom bolt (near the crank pulley). The bottom bolt is notorious for shearing and is a royal PITA to remove the left over bolt from the block without removing the engine. I would replace both bolts ASAP (I have had two of the bottom bolts fail on me).

Cheers,
Robin

I will try and bosh the 8mm onto the wee bolt the morra. I have a snekng suspicion it will be a beeyatch and not go on. Also, the bottom bolt seems to have worked itself loose most easily, is it best to replace before it shears / works loose again or will a good solid tightening be OK?

cheers
jj

mac · Post by **mac** » Sat Dec 29, 2007 9:52 am

The top bolt on mine worked loose and had been for some time ovalising the alloy of the alternator which started throwing belts - needed a new alternator.

Mac

robin · Post by **robin** » Sat Dec 29, 2007 10:27 am

jj wrote:
I will try and bosh the 8mm onto the wee bolt the morra. I have a snekng suspicion it will be a beeyatch and not go on. Also, the bottom bolt seems to have worked itself loose most easily, is it best to replace before it shears / works loose again or will a good solid tightening be OK?

cheers
jj

It should go without saying that there is no point tightening the 8mm bolt unless all three main bolts are loose (otherwise you're tightening against the clamp).

You must replace the bottom bolt - it will already have received shock loading from the flailing alternator.

You must tighten to something approximating the correct torque. For the bottom bolt that isn't all that much - if you overtighten, you stretch the bolt and it will then become loose again. Use threadlock on the bottom bolt.

IIRC, it's an M8 bolt into alloy, so it would be 25Nm; if it's M10 then it would be 45Nm.

Cheers,
Robin

jj · Post by jj » Sat Dec 29, 2007 3:48 pm

Thanks robin/mac all points noted- off out with my new bolts to sort it out.

I read a thread on SELOC about the ovalised hole problem but the bolt sits fairly tight in mine and doesnt look like it has ovalised.

monster hanogver though

so this should be fun!

fd · Post by fd » Sun Dec 30, 2007 5:30 pm

jj wrote:Thanks robin/mac all points noted- off out with my new bolts to sort it out.

I read a thread on SELOC about the ovalised hole problem but the bolt sits fairly tight in mine and doesnt look like it has ovalised.

monster hanogver though so this should be fun!

You should really remove it and have a look - you won't be able to tell if the top hole has ovalised if you don't.

I've had exactly the same thing happen and it wrecked the alt - I repaired it but that repair meant overdrilling the hole and pressing in an ali bush to restore the alt mounting bolt geometry . . . simple enough if you have the skills and tools . . . throw it in the bin if you don't.

As Robin says it's very important to replace the bottom bolt . . .

For the we 8mm tensioned a ratcheting spanner is very handy . . . and remember to disconnect the battery unles you want some arc welding practice . . .

Fd

Rich H · Post by **Rich H** » Sun Dec 30, 2007 5:34 pm

Deffo don't for get the batery... It makes you jump and there isn't much room for flinching like a girl under there...