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Dead battery, would not accept a charge. Car had not been driven for 2 months (we were out of town). I don't trust leaving the battery on trickle charge during our long absences so I just disconnect the negative lead to the battery and upon our return put it on trickle charge for a couple of hours.
Called AAA. Here is the test results:
AAA was able to jump start the car. I was told to just drive it on the freeway for 30 minutes to charge the battery. At 70 mph my amp meter showed only a very slight positive charge. I would have suspected a much stronger charging current on a depleted battery, probably confirming the alternator has an open diode???
Looking at Corvette America and Willcox, neither website shows an alternator matched for a 300/350 with AC. Do any of you have a recommendation for an alternator replacement and a harness connector if required?
I would purchase a diode, install it and see if it solves the problem. I believe you can also test a diode with a volt ohm meter, with more continuity in one direction than the other when hooking up to the legs on the diode.
Last edited by mark79,80; Jul 14, 2018 at 02:46 PM.
I would purchase a diode, install it and see if it solves the problem. I believe you can also test a diode with a volt ohm meter, with more continuity in one direction than the other when hooking up to the legs on the diode.
You are forcing me to learn new tricks. Been on the internet learning about diode repair. My options are to disassemble the alternator to see what kind of diodes I have. Not too keen getting into a soldering job. I could also just jump start the car and take it to an alternator shop for repair or order a new alternator but not certain which one to order.
Call a starter rebuilder in your town. Ask him to rebuild your alternator. If he has any bigger rotors or stators, tell him you are fine with it. But you want your front and rear frames.
You are forcing me to learn new tricks. Been on the internet learning about diode repair. My options are to disassemble the alternator to see what kind of diodes I have. Not too keen getting into a soldering job. I could also just jump start the car and take it to an alternator shop for repair or order a new alternator but not certain which one to order.
Regards,
Tom
On the alternators I replaced the diodes in, the job entailed just removing and reinstalling the nuts on the new diode. There was no soldering. I agree with another suggestion is to take it to a rebuilding shop if there is one in your area. In my area the few electrical rebuilders closed a number of years ago.
Another alternative is to purchase a rebuilt one locally. You could always send yours off to be rebuilt if you are concerned about keeping the car original, and there is not a rebuilder in your area.
I am thinking a '69 may need the round individual diodes (external regulator style alternator) rather than the one piece aluminum diode bridge found on the later models (with internal regulators). Still not a big deal to diagnose or service either way. Fix what you have is my advice.
On the alternators I replaced the diodes in, the job entailed just removing and reinstalling the nuts on the new diode. There was no soldering. I agree with another suggestion is to take it to a rebuilding shop if there is one in your area. In my area the few electrical rebuilders closed a number of years ago.
Another alternative is to purchase a rebuilt one locally. You could always send yours off to be rebuilt if you are concerned about keeping the car original, and there is not a rebuilder in your area.
Mark,
I just returned from NAPA and ordered a diode trio set. Their data base shows the 69 alternators have the screw on diodes. Will receive the set on Monday. Also got a good reference for a reputable alternator rebuild shop so that will be my backup. Thanks for push!
Originally Posted by dmaxx3500
a child could rebuild an alt in these
go find a video on it,,you pull the 4 screw around the case,and replace the brushs ,diode trio,
Thanks...Mark's post forced me to go online and educate myself. I'm going to give it a try. (Chi-town is my home town - will be visiting in September...Portillo's here I come!)
Originally Posted by stingr69
I am thinking a '69 may need the round individual diodes (external regulator style alternator) rather than the one piece aluminum diode bridge found on the later models (with internal regulators). Still not a big deal to diagnose or service either way. Fix what you have is my advice.
I'll pull the alternator tonight and take a look. If I have the screw-on diodes I'll do it, if not, I'm taking the alternator to the shop.
those black things in the middle are the brushes,push them and the springs back in there holder and use a tooth-pick thru the hole to hold em in,after the alt is back together,pull the tooth-pick out from the back side of the alt
did you mark the case halfs when you took it apart?,,they need to go back on the same way [its called clocking]]
No, I only ordered the diode trio but discovered a different problem. See below.
those black things in the middle are the brushes,push them and the springs back in there holder and use a tooth-pick thru the hole to hold em in,after the alt is back together,pull the tooth-pick out from the back side of the alt
Will do, or use a small plastic straw from an LPS or WD40 aero-spray can.
did you mark the case halfs when you took it apart?,,they need to go back on the same way [its called clocking]
Yes
]
What I discovered was a loose diode in the rectifier body (under top stud in photo below). The rectifier diode checks okay however it had broken loose from its solder joint on the rectifier body thus creating an open. The diode trio checked okay.
Go to drugstore and splurge on a sewing needle kit. Toothpicks and straightened paper clips don't make real good brush holder pins. 3 screws on brush holder-regulator. 2 are insulated. Make sure to put back in the right locations. I never took apart that rectifier. But then when i was doing alternators i had a bucket full of them. They either had 6 good diodes or got tossed.
Last edited by derekderek; Jul 15, 2018 at 04:52 AM.
Go to drugstore and splurge on a sewing needle kit. Toothpicks and straightened paper clips don't make real good brush holder pins.
Got the bushes pinned back using a straw from an aerosal can.
3 screws on brush holder-regulator. 2 are insulated. Make sure to put back in the right locations.
Have the grounded terminal identified.
I never took apart that rectifier. But then when i was doing alternators i had a bucket full of them. They either had 6 good diodes or got tossed.
Found a u-tube video on how to solder the diode back on the rectifier. By the time I purchase the butane torch to heat the rectifier body, silver solder, and flux, I might as well just have a shop rebuild the alternator. It looks like I have a GM 10SI alternator. Can you tell by looking at the serial number on the case whether it was a 37 amp or 62 amp alternator. I have AC so I would assume it would be 62 amps. I also found an 110 amp alternator upgrade kit for the 10SI but the stator looks huge and not sure if the rest of the electrical system could take a 110 amp load, or will the case have enough cooling ventilation holes to keep the rectifier cool? So now I am looking for a source for a new rectifier. If unable will then have the alternator rebuilt.
But a local rebuilder would probably have given you a rectifier. How full of wire is your rotor? Show me a pic of your stator. Low amp rotors are about half full. Higher amp ones pretty full. Harder to tell a high amp stator from a low amp unless they are side by side.
But a local rebuilder would probably have given you a rectifier. How full of wire is your rotor? Show me a pic of your stator. Low amp rotors are about half full. Higher amp ones pretty full. Harder to tell a high amp stator from a low amp unless they are side by side.
Okay, I think my helmet fire is about extinguished. I found a link to a nice 10SI rebuild kit.
It is better to learn to fish, than it is to buy a fish.
I had to purchase the rod, reel, and bait, to catch this fish...to include having to take the alternator case to a repair shop to have new bearings installed. Not complaining...it was a fun learning process thanks to CF help. For those of us that have a limited tool inventory, by the time you purchase the correct tools for the job, it is cheaper to just buy the fish!
Right now, just waiting for the rebuild kit to arrive. By the way, my alternator did not have the resistor installed. The rebuild kit includes one so I assume it should be part of the system?
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
good job...about buying a fish...... Buy a man a plane ticket and he flies for a day,
push a man out of an airplane and he'll fly for the rest of his life.
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Alternator Open Diode Help
