Alternator Belt Dusting

[Ian_Rob]

I am getting a lot of black dust from my alternator belt this season which I am putting down to abrasion caused by rust on the pulleys? The belt is correctly positioned in the correct grooves but slightly slack - depressing by 15mm or so rather than the recommended 10mm. It may not last very long but to slow further rusting, is there any reason why I shouldn’t spray paint the pulleys and grooves after I removed the rust ?

Older D1-30’s seem to have been supplied with painted pulleys whereas the pulleys on later versions weren’t.

Is there a better inhibitor than paint that wouldn’t cause slippage or degrade the belt?

Thanks.

 

[savageseadog]

The paint will simply abrade off, probably in minutes.

 

[ChromeDome]

Once polished by the belt it will remain so if used regularly.

Lots of belt sprays ('belt dressing' et al) around, but no personal experience. Suppose most universal sprays will wear off in seconds or, worse, make the belt slip.

 

[PetiteFleur]

Tighten the belt. Alternatively fit a Cogged Raw Edge vee belt which transmits more hp than a standard vee belt, must still keep it properly tensioned.

 

[WoodyP]

If it's a v belt then Beta for instance recognized the problem and converted to multi groove pulleys and belts which cured the problem. Could you do the same with your engine. The higher output alternators cause the most dust.

 

[Daydream believer]

Are you sure that the belt has not bottomed on the pulley. It needs to sit in the groove. Once it bottoms out, no amount of tension will stop it slipping & you will only put strain on the bearings. Check the top edge of the belt to see if there is an "edge " turning up where it has abraded the belt.
It may also help to get a different belt with a wider section. I had belt slip for a long time. I changed the belt pattern & although it is slack in comparison there is no visible slip & the black dust from the belt is no longer visble. It now sits on the outer circumfrence of the pulley

 

[Ian_Rob]

All useful stuff. Thanks very much.

 

[Slowboat35]

I think the mention of rusting is the key here.
Once rust has formed the even polished finish is lost as the pulley faces become pitted and this pitting contributes greatly to the abrasion of the belt.
When mine did this I took the pulley off, mounted it on an electric drill and dressed it carefully with a strip of very fine emery paper glued to an old ruler. It worked for a while but the rust returned, so I'd suggest preventing the rusting is a top priority. Toothed belts seem much better in this respect.

 

[MikeBz]

I had this problem after fitting an alternator-to-battery charger which tends to load up the alternator more. Solved by linishing the pulleys (fine sandpaper wrapped around a screwdriver blade very carefully applied with the engine running) and fitting a better belt than the standard Volvo item (from Gates belts IIRC).

 

[LittleSister]

Excessive heat in the engine compartment will also cause increased dust.

But whatever, in the meantime having the belt slack isn't going to help.

 

[Poey50]

Before upgrading to a serpentine (multi-ribbed) belt I had a lot of problems with belt dust because of some rust on the pulleys. I found the small wire brush that fits on a Dremmel to be ideal for keeping the rust down.