1.4mpi AQW without aircon. Had an electrical issue. Removed and dismantled alternator to find one of the brushes has 4mm left. 

 

On looking it seems the part number for this particular voltage regulator is 047903803. Looking on eBay I see a VEMO branded one at £46.44 or a Hitachi branded one for £67.94. Are these about the right price?

 

The regulator that came off has a separate part for the brushes joined by a metal connector, and that part has two screw holes. The ones on eBay seem to have this integrated and no screw holes present. (They state they are actual pictures of the item.) It looks like it would probably fit as the major bits seem to be in the same place, but looks different enough for me to query hoping someone who has replaced one knows.

 

Edit: looking at alternator prices it seems some 90a alternators are cheaper than 70a. The main difference I see is that the 90a come with a pulley for 6 ridged belts, whereas the 70a are for 5. Would it simply be a case of swapping over the pulley?

 

Many thanks.

Edited 9 October, 20196 yr by anewman
90a upgrade

I replaced the brush pack on mine and it was only £25, those prices seem excessive to me.

OE part is £120 here https://www.oemvwshop.com/047903803a-voltage-regulator-skoda-fabia-6y-p234779/ and most of their prices for other things seem reasonable. At that price I'd be expecting a whole alternator 😂

I reckon it will make more sense to pick up a whole alternator from a scrappie not necessarily a Magneton one, taking the aux belt with it if still on the car; I guess you've seen this page of variants:

https://skoda.7zap.com/en/cz/fabia/fab/2002-225/9/903-903000/#1

Seems to be a few options that'll fit AQW, 70A or 90. Not sure which belt will fit a 90A one if used on a car without A/C though.

 

 

 

 

Edited 9 October, 20196 yr by Wino

8 minutes ago, Wino said:

I reckon it will make more sense to pick up a whole alternator from a scrappie not necessarily a Magneton one, taking the aux belt with it if still on the car; I guess you've seen this page of variants:

https://skoda.7zap.com/en/cz/fabia/fab/2002-225/9/903-903000/#1

Seems to be a few options that'll fit AQW, 70A or 90. Not sure which belt will fit a 90A one if used on a car without A/C though.

 

I found this one which looks like it should be a straight swap, and it seems quite clean. Also I imagine a voltage regulator would be much cheaper if it needs one. It's a Bosch 047903015Q.

 

https://www.ebay.co.uk/itm/1634010163

Edited 9 October, 20196 yr by anewman

Yep, makes sense to me. It does have a different part number belt associated with it, but as you suggest that may be a work-aroundable thing with a pulley swap (that's not always easy though).

On 09/10/2019 at 14:59, Wino said:

Yep, makes sense to me. It does have a different part number belt associated with it, but as you suggest that may be a work-aroundable thing with a pulley swap (that's not always easy though).

Just swapped it. The Bosch 047903015Q was a straight swap for the Magneton. (Funny that Skoda parts said alternator and voltage regulator were both "obsolete".)

 

Most electrics off it tops out at 14.5v. With everything switched on (headlights, fans on full, rear demister) it's around 12.8v at idle. This is better than before, but concerned it's still a little low.

23 minutes ago, anewman said:

Most electrics off it tops out at 14.5v. With everything switched on (headlights, fans on full, rear demister) it's around 12.8v at idle. This is better than before, but concerned it's still a little low

 

Was that measuring across the battery posts, or where?

 

Try adding a few revs and see if that perks it up.

 

If not: Try with both meter probes at the alternator, positive on the output stud, negative on a scratched-clean bit of the body.  If it's significantly higher there (with the same loads on), you have a poor connection in either the positive or earth leads. Main engine earth at top starter bolt would be my first suspect, remove, clean up refit, re-measure.

You could be a little more systematic with the diagnosis, and move each meter probe around to see where the voltage drop is happening, i.e. move the positive lead back to the battery and see if most of the loss is still there, or not.

Edited 10 October, 20196 yr by Wino

IIRC 1.4 MPI do tend to read about 12.7V under load, only the later engines with the 90A alternator and ECU controlled charging will read 14.4V.

There isn't ECU controlled charging on any Mk1 Fabia.