my 85 again

[rob66f100]

ok i been burning up altenators on my 85 they still charge but only if the load is small start turning on the lights and i get about 10.5 vdc kill @ the battery when it was working i was getting around 4.5 vdc on the field not that it's messed up again im getting 10.3vdc again on the field alt is grounded and the rest of the grounds are good what kinda reading should i get on the field for a good alt and any ideas whats causing this trouble oh yea regulato is new too rob

[64 f100]

Belt worn out? Checked the wiring for resistance. Checked for shorts? Could be a bad regulater, even though new. Where you getting your alternaters?

Rich