so last week my dad calls me and tells me that the truck died and the battery tester/charger is saying that the alt is giving low voltage. so i sent him a new regulator and brushes. after screwing with the tensioner. he got the alt out and installed the new parts and now the gauge reads slightly higher than middle of the gauge. yet the tester/charger still reads low voltage.

now he ran the test with the truck off so i told him to do it with the truck running. i also have a multimeter in my tool box so what test can i tell him to do?

also apparently he had a hell of a time with the tensioner. the pulley does not seem to have a place for a wrench or a bolt that the aftermarkets have. i dont remember having such a bad time with it when i replaced the belt but i am mechanically inclined and he isnt. have any of you had issues with the tensioner?

 

Have him run a voltage test at the battery and at the back of the alternator to see if they are the same. The test should be done with the motor running and with lights,AC on or with enough things on to load up the alt. He should have at least 13.5 volts under load.

Not sure about the tensioner every one I've seen has had a bolt on the pulley to work it with and so the pulley can be replaced. Other than the older ones that has the square hole in them.

 

i will have him do the test tonight. the tensioner has a mounting bolt but the pulley has nothing in it. i will check it out when i get home tomorrow

 

I think the original tensioners have a square hole for a 1/2 drive breaker bar to attach. Agreed, 13.8 to 14.2 volts on voltmeter, I never rely on the trucks instruments, they are for visual reference only. And besides they look nicer than idiot lights.

 

Just because the alternator is putting out 13.8 to 14.2V does not mean its putting out full power. You may have diodes burnt out and only putting out 1/3 of the amperage and the battery is not being charged enough.

You need to load test the battery and alternator, some places will do free charging system checks.

 

13.8 and above IS full power, and engine running is load testing.

 

so the alt is fine now and i figured out what his problem with the tensioner was. the bolt that holds the pulley to the tensioner is missing. the belt is the only thing holding it in place. does anyone know what size bolt it is?

 

If it's a 5.0 or 5.8 it should be a M10-1.5 x29mm.
My bad I reread you post that is the tensioner bolt size.

 

ya i need the bolt going through the pulley

 

never mind! the tensioner decided it didnt want to part of the truck anymore. this morning i left my house at 7am to take a 3 hour round trip to pick up a moving truck and 10 miles down the road there was a loud screech and no more tensioner. luckily i was able to pull over quickly. had to pull the bracket to get at the sheered off bolt from the back side and had us up and running by ten.

to make a long story longer i dont need the bolt anymore.