Volvo AD41 Alternator belts always loose

[sickcat]

New belts stretch after running for a bit. Are you near the end of the adjustment on the alt arm? Overtightening belts just leads to cooked alt and water pump bearings. With new belts adjust them for about 1/2" "play" and check them after about 30 minutes running time. 1/2" play doesn't mean having to put a bunch of force into stretching the belt - it means using a thumb and finger to deflect the belt to the side.

You can also get a bolt that is about 1/2" longer (and no not from your VP dealer! ) and back it up with a nut. Also use washers to give the adjustment bolt on the alt arm more "grab".

[neversink2]

Originally Posted by zarco

I have another arm/bracket and pulley if you find yours to be bad.

Thanks for the offer and thanks everyone for your help.

Took the arm off today and found that the holes are 1/8 bigger than the bolts so my dad welded the holes up, re-drilled to a closer size and re-painted the arm. He also made a turnbuckle tensioner that fits between the pulleys. We set the tension per factor spec and snugged everything up, then removed the tensioner. It worked great! The belts are much tighter than previously and hopefully will no longer slacken due to poor bolt/hole size mismatch.

The problems started after about 400 hours when we changed belts. Before that, the engine was a brand new repower and everything was factory so I assume tension was factory set and we were never able to achieve that level of tension due to limited access. We're hoping the turnbuckle fixed that. I'll post an update after our next trip.

[BiggestT]

Great news Chris, glad you got this resolved.