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Alternator fan belt

Posted: Mon Jul 11, 2016 8:40 am
by simmit
Is the alternator fan belt on MB same as standard Ford (for say Scorpio)? Either way does anyone have a part number for the MB belt. Previous owner fitted one that is too narrow and it's rubbing on the bottom of the pulley 'V' groove.

Alternator fan belt

Posted: Sun Apr 22, 2018 11:27 am
by drcdb15
ALERT: Please note that the QH codes shown on the MESS site may not be quite correct. The belts should BOTH be 13mm wide. The QH belt QBA 1225 is a 9.5mm belt, which explains why Simmit found it running too deep into the pulley groove. The correct QH code is QBB 1225 - but this seems longer than the Gates belt on my car, so I suggest the correct QH belt for the alternator should be QBB1200.

Also note, the belts given on the GATES web site for the Scorpio/Granada do NOT match the lengths used by Middlebridge - I don't know why, maybe the MB routes differently to clear the bodywork, but anyway, they are not the same.

My car has Gates belts: power steering 6470MC (1000mm long); alternator 6478MC. These are both AVX13 profile, ie 13mm wide, cogged V-belts. The length in the Gates numbering increments by 25mm for each last digit increase:

6478MC - 1200mm long
6479MC - 1225mm long
6480MC - 1250mm long
6481MN - 1275mm long - Capri 2.8 (among others)
6482MC - 1300mm long

On the MESS site Mick Gaughran mentions using a 'Capri 2.8 belt' for the alternator when converting to alloy rocker covers. I suspect that this is the 6481MC belt, which gives an extra 75mm over the 6478MC, allowing the alternator to be moved an inch or so closer to the offside so as to clear the alloy rocker cover filler hole.

For those who didn't know (and that includes me prior to this investigation) it seems Gates are the originators of the V-belt which they invented in 1917, and have been the presumed gold standard ever since. I'm obviously not endorsing their products but if you want an equivalent from another manufacturer it would seem sensible to take the Gates reference number as your starting point.