after many many miles my mazda alternator belt broke. so i go replace it w/ a belt from ABC(this belt actually had some teeth rather than being smooth like my stock one) and after about 200 miles it snaps. so i then go to pep boys and get one which was smooth, similar to the stock one. well after about 150 miles, that snaps too(this time it snaps while i'm pulling into my driveway...whew!). so now i am at a loss. i was planning on getting a mazda belt anyway but this just doesnt seem normal! 2 belts snapped in 4 days? can anyone give me insight on this? when i put them on i do give it enough tension. i know they eventually stretch and i have to re-tighten it, which is what i did on the first replacement belt after 100 miles...but it broke anyway.

-jet-

 

How tight did you Install them?

 

i usually leave about 1/2" of give when i press down on it after initial install. is that too much? too little?

 

Why do they break?
Too tight.
Too loose.
Pulley is warped.
Alternator is siezing.
Belt has bad quality control.

I use a 1/4" deflection on the LONGEST span between pulleys. It sounds like yours is too loose. Do you see fine rubber powder in your engine bay?


-Ted

 

edit: i rechecked everything and yeah, on this 2nd break i see fine black rubber powder all over. i guess this means something is grinding? it's getting un-aligned or something?

 

Try and tighten the belt and see if that works. The "ABC" belts you mention sound like the Gates belts, and these need to be on the tight side - they tend to get loose the more you run them. I typicall check belt tension at least once a month, by habit...

You might want to check the pulleys for warpage or misalignment - watch the while the engine is idling...



-Ted

 

thanks for the tips. will do!