Generator stopped turning...

Good morning all. '66 CJ5 and the generator is stamped 12V by Prestone.

First crank of the day, pulled out of garage and down driveway in reverse, then headed down the road a few hundred yards in first gear and the belt began squealing and amp light came on. Opened the hood and found generator not turning. Shut engine off and was able to turn it by hand. Cranked engine and drove it for 4 miles without further incident.

Questions from a bright green rookie:
1. Should I able to turn the generator by hand if the belt is at proper tension - i.e., could it be that the generator was not turning because belt is too loose? Belt has about 1 inch of play when I pull up and down on it. Loose belt might be tighter as RPMs go up driving down the road? Hey, a free solution is worth a shot, right?
2. Assuming the belt is properly adjusted is there anything that I, a very mechanical rookie, can do or is it time to take it off and go see my favorite mechanic?

Thanks for any advice.

 

Would agree that the belt is too loose, but you should be able to turn the generator by hand-without the belt. At essentially zero rpm, there should be no load on it and if it doesn't turn easy, the bearings are VERY shot. One other possibility would be a malfunctioning regulator that is putting a maximum load on it-with a loose belt, that would definately cause it to squeal. What is the amp gage doing?

 

Thanks guys. After receiving the suggestion about belt tension I tightened it up for about a half inch play and the squealing was worse which makes me think bearings are going based on the discussion you guys had. I shut it down and didn't have time for more investigation. The belt seats nicely in the pulleys so i think it is the correct one but will check the part number to be sure. I will next remove the belt and turn by hand as suggested - I suspect I'll be able to "feel" bearings that are shot. Thanks for the advice.

 

I removed the belt, spun the generator by hand and metal shavings appeared... The part tag says Prestolite GJP 7402A. Can I go to my nearest NAPA or what are your suggestions?

 

If you are halfway handy, take it apart.

If it's just the bearing, get the number off it. Buy a new bearing at the auto parts place. Put in some new brushes while you are at it.

 

My brother in law at NAPA got me a Wilson replacement.... Want to make sure I reconnect the leads right: when looking from the left front fender towards the engine, on the Wilson there is a silver lead closest to the engine and a brass one furthest away. On the old Prestolite I noted the green wire was attached closest to the engine and the red was furthest away. Reconnect same way? Any screw up if it's different for some reason?

 

also, need to remove the old belt pulley - what is the trick to keeping generator from spinning?

 

An impact wrench will zip them right off-otherwise a strap wrench will hold the pulley or-if desperate, a chain type visegrip at the risk of maring the pulley.