I hope this is of some use to somebody, but I have just had my alternator fail on my 160,000 TDI Octavia. I was just pulling on to the carpark at a customers, when there was a clunk (the freewheel pulley had seized and come off!) and the battery light came on, and steering got heavy. Anyway, after much searching to locate a replacement alternator, (they can't get them at Halfords, and Skoda want £270! even recon ones are £170.) I had to remove the old one. The way I did it was to undo the earth lead on the battery first, remove the engine cover, then undo the power steering pump and the bracket which holds the rigid pipe (makes it more moveable) to move it out of the way, undo the tensioner, removing the pulley first (easy job, just 3 x 6mm allen bolts). I pulled the belt out of the way from underneath, having first removed the undertray, and disconnected the alternator wiring. I undid the radiator fan, so it would give me more clearance, and having undone all the bolts for the alternator, was able to squeeze the alternator up through the gap, bending the radiator hose out of the way. This all sounds simple, but as it was trial and error, it took me about an hour. I think you could do it easier by removing the a/c pump and dropping the alt out through the bottom, but I thought it looked trickier to locate the bolts.

I am still to put the new one back in, so if I find any problems I will add to this thread

Cheers

Neil

WARNING

If you're thinking about removing the air con pump, make sure you don't need to move it more than the reach of any flexi pipes attached to it. If you open the air con circuit, you'll need to have the system regassed.

Managed to get it back together last night (mostly). The alternator I was given did not want to go straight in, as the gap between the mountings on the alt were smaller than the distance on the engine, so I had to use a socket and G Clamp to pull the threaded parts through the casting on the alt, after that it went on fine. It took me ages to work out what to do with the belt and tensioner, so another visit to the Briskoda website was called for, which told me that I could move the tensioner with a 19mm spanner, so with a bit of tube on the end of the spanner, and the belt on all the pulleys except the a/c one, which was nearest to me underneath, I pulled the tensioner load off and slipped the belt over the last pulley, no bother. One tip I can give is to protect the radiator when your are getting the alt in place, as the fins will take a bashing if you don't, assuming like me you have removed the o/s fan.

If you have the time, it is definitely worth doing the job yourself, given the cost, it is fairly straight forward, just allow plenty of time, and get some thin gloves, as the plastics cut your hands to hell when your spannering the bolts.

All I have to do tonight is get the covers back on, and fingers crossed, start it!

Hope this helps

Neil

Managed to get it back together last night (mostly). The alternator I was given did not want to go straight in, as the gap between the mountings on the alt were smaller than the distance on the engine, so I had to use a socket and G Clamp to pull the threaded parts through the casting on the alt, after that it went on fine. It took me ages to work out what to do with the belt and tensioner, so another visit to the Briskoda website was called for, which told me that I could move the tensioner with a 19mm spanner, so with a bit of tube on the end of the spanner, and the belt on all the pulleys except the a/c one, which was nearest to me underneath, I pulled the tensioner load off and slipped the belt over the last pulley, no bother. One tip I can give is to protect the radiator when your are getting the alt in place, as the fins will take a bashing if you don't, assuming like me you have removed the o/s fan.

If you have the time, it is definitely worth doing the job yourself, given the cost, it is fairly straight forward, just allow plenty of time, and get some thin gloves, as the plastics cut your hands to hell when your spannering the bolts.

All I have to do tonight is get the covers back on, and fingers crossed, start it!

Hope this helps

Neil

Bump:

Hi guys. Can anyone tell me how many bolts secure the alternator. I removed the two long 13mm bolts as per the Haynes manual - one top and one bottom, but it doesn't want to move. The v-belt and tensioner are already removed. The twin point electrical connector is removed, as is the battery cable and nut. What have I missed, that is preventing me from removing the alternator?

The bushes are very tight, so you might need to lever it off. The bracket mouldings can be fragile so try to pull it straight. When it's out I'd recommend you stand it on its side on a bench, put a long socket on the outside over the bush, put the bolt through the middle and then tighten it to pull the bush out slightly; it'll go back on a lot easier that way.

Interphase: Many thanks Your advice was totally correct, it was just being held by an interference fit via the spacers. It came of easy enough on an SDI - I just did the following.

1. Disconnect battery earth - 10mm nut.

2. Remove top engine cover - 2 * 10mm recessed nuts, so 1/4" drive 10mm socket required.

3. Using a gear wrench serpentine belt tool, (so much easier than a long 16mm 0 degree-offset ring spanner) I removed the tension from the v-belt tensioner, and secured it under tension with a 4mm Allen key (a small nail would also be fine.)

4. I then removed the three 13mm bolts securing the v-belt tensioner ( easy to access with a 13mm ratchet spanner or combination or socket) and removed tensioner from top of engine - it comes up easy with loads of room!

5. Removed the two long 13mm bolts securing the alternator (top and bottom and from the left side looking into the engine bay.)

6 Following interphase's advice, I then levered the alternator out, as it was now just being held by the tension from the spacers (see advice from interphase - above.)

7. Then turning the alternator so that I could see the back, I pulled out the two-pin connector - I undid the battery cable secured by a 13mm nut - I undid the cable securing nut with a 8mm 1/4 drive socket.

8. I then removed the alternator from the top of engine - it came up easily with loads of spare room.

9. Fitting was a reversal of the above, using a new v-belt. Don't be intimidated fitting a v-belt on an sdi - there are not many pulleys to worry about. Make sure the arrow on the belt faces the direction of rotation, and if you get confused remember that the belts grooves fit into grooved pulleys, and that the smooth back of the belt, fits against smooth idler pulleys.

Ps: You do not need to go under the car, and you do not need to remove the power steering pump - everything is done from the top down as described above.

Pps: I changed to a spare alternator because I heard my Pulley clutch going last night - at tickover it just goes pop, and your battery light comes on, and it starts screeching as you increase power demands - lights. demister etc.

The pulley had in fact disappeared completely and the tensioner ensures that the v-belt is driving the bare shaft. I hear that at higher rpm's the pop becomes a bang!

TTFN.

Edited 13 January, 201115 yr by Talisman

thats great info , thanks . , mine has gone today i thing so will need to come off tomorrow , i had a look today and didn't have a clue where to start ..

 

 

anyone know if its basicly the same on a 1.9 tdi ? 

 

many thanks d 

thats great info , thanks . , mine has gone today i thing so will need to come off tomorrow , i had a look today and didn't have a clue where to start ..

 

 

anyone know if its basicly the same on a 1.9 tdi ? 

 

many thanks d 

 

From memory, yes.

cool . it looked a bloody nightmare but from that sounds not to bad at all

On 13/01/2011 at 17:40, Talisman said:

Interphase: Many thanks Your advice was totally correct, it was just being held by an interference fit via the spacers. It came of easy enough on an SDI - I just did the following.

1. Disconnect battery earth - 10mm nut.

2. Remove top engine cover - 2 * 10mm recessed nuts, so 1/4" drive 10mm socket required.

3. Using a gear wrench serpentine belt tool, (so much easier than a long 16mm 0 degree-offset ring spanner) I removed the tension from the v-belt tensioner, and secured it under tension with a 4mm Allen key (a small nail would also be fine.)

4. I then removed the three 13mm bolts securing the v-belt tensioner ( easy to access with a 13mm ratchet spanner or combination or socket) and removed tensioner from top of engine - it comes up easy with loads of room!

5. Removed the two long 13mm bolts securing the alternator (top and bottom and from the left side looking into the engine bay.)

6 Following interphase's advice, I then levered the alternator out, as it was now just being held by the tension from the spacers (see advice from interphase - above.)

7. Then turning the alternator so that I could see the back, I pulled out the two-pin connector - I undid the battery cable secured by a 13mm nut - I undid the cable securing nut with a 8mm 1/4 drive socket.

8. I then removed the alternator from the top of engine - it came up easily with loads of spare room.

9. Fitting was a reversal of the above, using a new v-belt. Don't be intimidated fitting a v-belt on an sdi - there are not many pulleys to worry about. Make sure the arrow on the belt faces the direction of rotation, and if you get confused remember that the belts grooves fit into grooved pulleys, and that the smooth back of the belt, fits against smooth idler pulleys.

Ps: You do not need to go under the car, and you do not need to remove the power steering pump - everything is done from the top down as described above.

Pps: I changed to a spare alternator because I heard my Pulley clutch going last night - at tickover it just goes pop, and your battery light comes on, and it starts screeching as you increase power demands - lights. demister etc.

The pulley had in fact disappeared completely and the tensioner ensures that the v-belt is driving the bare shaft. I hear that at higher rpm's the pop becomes a bang!

TTFN.

This was absolutely so helpful that it took me 1.50 to replace the alternator and out of that 50 minutes in pretty much darkness as it got too late. I will also like to highlight that spacers gave me a bit of a challenge as I did it all in the driving bay (no vice etc.). I used small socket set extender and the equivalent size socket on top of the spacer to whack it back - and good old wd40 for a good measure as I replaced with the refurbished alternator. Again - many thanks for the steps Talisman.

Just a note. If your alternator freewheel pulley has gone (mine disintegrated), then with a cheap, splined tool and a long hex/torx set (can't remember which), you can just replace the pulley. Did mine in about an hour or so. Just relieve the tension on the V belt (obviously). Only the removal of the fuel filter housing is required (undo and set to one side without disturbing the filter). Really simple job and cost around £25 for the pulley (I used a Gates item), and a few quid for the splined tool.

This is interesting, as I have an issue which may require some alternator work.

The alternator fusible link in the battery fuse box has burned up; I only replaced the fusebox a year ago. The fuse link is rated 110A; despite the winter and it's demands on the car's electrical power, I think something else is sucking power causing the fuse to blow. And when people say 'earth fault', I reach for my revolver... finding earth faults in an old car is gonna take weeks!

I read somewhere that it's common, the Mk1 VRS blowing alternator fuses. Considering it shuts the car down, I have to sort this out, not just patch it up. I also read there can be arcing to the 110A fusible link, but I'm not sure about this. Something else would cause arcing, no?

This is where a VAG scanner would be helpful, but I don't have one.

Does anyone know if the alternator belt tension could be causing the problem? I'm sure the alternator itself is fine

I would definitely get a diagnostic on the electrical problem. Like you, I reckon electrics are a dark art and 'earth fault' is not far off torching the car and buying another.

You'll know when the pulley is on the way out when the belt/pulley starts screeching at you. When I released tension on the V belt and tried to rotate the pulley, it actually moved up and down and was very stiff. On removal, most of the roller bearings fell out and the cage had partially disintegrated.

If you do replace, put a dab of grease around the bearings - helps keep the moisture out. My old one was dry as a bone and a little rusty too.

Good luck with those electrics.

On 14/02/2026 at 02:26, ogpuprison said:

This is interesting, as I have an issue which may require some alternator work.

The alternator fusible link in the battery fuse box has burned up; I only replaced the fusebox a year ago. The fuse link is rated 110A; despite the winter and it's demands on the car's electrical power, I think something else is sucking power causing the fuse to blow. And when people say 'earth fault', I reach for my revolver... finding earth faults in an old car is gonna take weeks!

I read somewhere that it's common, the Mk1 VRS blowing alternator fuses. Considering it shuts the car down, I have to sort this out, not just patch it up. I also read there can be arcing to the 110A fusible link, but I'm not sure about this. Something else would cause arcing, no?

This is where a VAG scanner would be helpful, but I don't have one.

Does anyone know if the alternator belt tension could be causing the problem? I'm sure the alternator itself is fine

If this is the same issue that has plagued us all, were the fuse box on the battery melts? If so, it's very, very common on the VAG range of this year; Golfs, Seat, Ibiza, TT, etc.

Search Results for Melted Fuse Box

Example

Hey thanks! However I'm aware of the alternator cable getting hot and resistance build-up, just wondered if the cable can be cleaned up at the alternator end and if there's a specific resistance I should be aiming for. I' should receive the fusebox tomorrow so intend to risk snipping alternator cable and re-crimping the loop connector. I got some 16mm w/8mm hyole ones, just hope they're up to the job. These crimps didn't state their accepted current, I'm just gonna go for it... if there's enough cable to pull up, that is. If the issue is common it wouldn't surprise me if it's been done ten times before by previous owners!

It's crazy that the various fusible links are so close together and their high-current connectors are a bit exposed if you ask me.

Do the real skoda hardcore re-route these to ensure a more reliable electrical system? The amount of diagnostic weirdness these fuseboxes and their connectors can cause blows my mind

...all done, but had to exchange the loop connectors for ones with a 6mm hole. I only cut off about a centimetre as there wasn't much slack to play with; scrubbed up the end, then used flux and solder to reduce oxidation

Getting them onto the cable itself was a struggle but they crimped up good. Let's see how long the fusebox lasts this time

Excellent work, got a photo of it all finished?

Actually I didn't take any pictures but here's what's left of the fusebox cover!

I've driven about 150 miles since doing it, took a look today ands looks un-melted thus far. It is still hot on the alternator cable side of the new box, sadly...so one day I need to trace the alternator cable and see if there are any other sections that are corroded/exposed/whatever. But the weather is so **** I can't face it right now

Wow, that's done a proper job melting that!

If alternator cable is hot and you suspect a high resistance due to corrosion then you could maybe just disconnect at the alternator and at the "big" fuse and fit a new cable between the two?.......just leave the old cable in place and fit the new cable in a route to your liking ?...until the weather gets better!!

You mention a "scanner" would be helpful, as far as I know your mk1 Octavia doesn't have a control unit as such for the charging system, it's control unit is the regulator.

Regards a "specific resistance", resistance isn't really worth checking as it's done with the engine switched off....... checking voltage drop under load IS worth doing.

Have you considered bypassing the big fuse and just hard-wiring the alternator cable to the battery terminal?....the more connectors then the greater chance of resistance?

Well, fuses are there for a reason; I said to my mate,'why do we need a fuse between alternator and battery' when the alternator has a regulator.. and he said ' cos the regulator could fail'. Well yeah, but why not carry 4 spare wheels cos you might blow 4 tyres? Sure you get my drift. But it seems more like the cable was burned up and as a result, had burned the insulation off the next cable to it (the 110A car systems cable). Or the other way round.

I've driven loads since I repaired it, the cable insulation and fusebox cover all look in good condition, so I'l just keep an eye on it. I did go a scrapyard in cheltenham today and tried pulling an altetrnator cable out of a Golf (07 plate) but it was too hard without any tools. I might go back and get it (<£10 he said) if I can figure out how it comes out. I don't think it's part of a larger loom so should be possible

Sounds like keeping an eye on it is the thing to do.