Hans1965 Posted August 20, 2022 Share Posted August 20, 2022 Dear all, my 52 Pontiac, the 49 Buick convertible and now the 12 V 53 Buick, they have all the same problem. The charge indicator gauge showed me for a while the generator is charging. After a few hundred miles of driving they all stopped doing that and are just discharging the battery. Does the voltage regulator need some maintenance or adjustment? Does the generator needs something? Are the gauges prone to failure? I oil the generator slightly with a few drops of engine oil and I make sure the driving belt is not too strong. Today I am going to take my multimeter to check it out. But is there something typical that I should be aware of? Thanks a lot. Hans Link to comment Share on other sites More sharing options...
Rusty_OToole Posted August 20, 2022 Share Posted August 20, 2022 Once the battery is fully charged the gauge will drop to 0 or close to it. This can take some time if the car is not in regular use and the battery not fully charged. Best thing to do is test the battery with a volt meter with the engine stopped and also with the engine running. Voltage should be between 6 and 6.6 when stopped, slightly higher when running, up to 7.2 if you rev the engine to 1500 or 2000 RPM. If voltage is low and does not change or goes down when the engine is running the generator is not charging, this could be a faulty voltage regulator, generator, loose fan belt, faulty wiring. 3 Link to comment Share on other sites More sharing options...
Rusty_OToole Posted August 20, 2022 Share Posted August 20, 2022 The voltage regulator has points like ignition points or like a solenoid switch. Sometimes they stick or get burned or corroded. It is not hard to take the cover off, inspect and clean them with a points file. The brushes in the generator can stick and fail to make a good connection, or just wear out. Check if they are moving freely and not sunk below the level of the brush holder. First you need to do a few tests and see where the problem is, if there is a problem. If the cars are starting and running normally there may not be anything wrong. If the charging system is not working you will know it when the car fails to start. 1 Link to comment Share on other sites More sharing options...
billorn Posted August 20, 2022 Share Posted August 20, 2022 What happens if you turn on the headlights while its running? Link to comment Share on other sites More sharing options...
Hans1965 Posted August 26, 2022 Author Share Posted August 26, 2022 The 53 that I am driving now is definitely not charging. I took the battery out and my charger indicated it is at 20% only. When I switch on the head lights, the needle in in the gauge goes well done, so it is draining the battery. Yes, I need to find my multimeter and make some tests. I just wonder that it happens to almost all my cars, if there is something to start with. Link to comment Share on other sites More sharing options...
EmTee Posted August 26, 2022 Share Posted August 26, 2022 Are the fan belts tight? Link to comment Share on other sites More sharing options...
Rusty_OToole Posted August 26, 2022 Share Posted August 26, 2022 Generator systems are not as reliable or long lived as alternators, and we are talking about cars over 50 years old. But it does seem you are having a run of bad luck. Normal life of a generator is 20,000 to 30,000 miles. Brushes and regulators are more likely to stick if the car is out of commission for a long time but these are easy to fix. 2 Link to comment Share on other sites More sharing options...
EmTee Posted August 26, 2022 Share Posted August 26, 2022 The generator on my '38 quit working recently and upon disassembly I didn't see anything wrong, other than it was pretty dirty inside and the commutator was black. I just cleaned it up and reassembled it and it's working fine now (knock on wood)... Before: After: 2 Link to comment Share on other sites More sharing options...
dodge28 Posted August 27, 2022 Share Posted August 27, 2022 Rusty-Otoole just gave you the answer. It could not be said better. The place to start is remove the generator from the car and dis assemble , wash with varsol.. Make sure the brushes move freely in the brush holders Hold the assembly in a vise, ground one battery cable to the vice and touch the other battery cable to the field. The generator should spin like a starter motor. Do not forget to polarise the field after installing. STEP 2. disconnect the battery ground cable and clean the contacts in the voltage regulators., Most electrical problems are poor ground . The 53 Buick should not be too problematic because it is a 12 v system 1 Link to comment Share on other sites More sharing options...
Hans1965 Posted August 29, 2022 Author Share Posted August 29, 2022 On 8/26/2022 at 2:35 PM, EmTee said: Are the fan belts tight? Yes, they are. Not too tight, but the thing is spinning. Link to comment Share on other sites More sharing options...
Hans1965 Posted August 29, 2022 Author Share Posted August 29, 2022 On 8/26/2022 at 3:29 PM, EmTee said: The generator on my '38 quit working recently and upon disassembly I didn't see anything wrong, other than it was pretty dirty inside and the commutator was black. I just cleaned it up and reassembled it and it's working fine now (knock on wood)... Before: After: I give it a try, thank you! I had disassembled generators and starters before, that's not difficult. Thought the change the voltage regulator is the culprit is higher. Link to comment Share on other sites More sharing options...
Hans1965 Posted August 29, 2022 Author Share Posted August 29, 2022 On 8/27/2022 at 5:08 AM, dodge28 said: Rusty-Otoole just gave you the answer. It could not be said better. The place to start is remove the generator from the car and dis assemble , wash with varsol.. Make sure the brushes move freely in the brush holders Hold the assembly in a vise, ground one battery cable to the vice and touch the other battery cable to the field. The generator should spin like a starter motor. Do not forget to polarise the field after installing. STEP 2. disconnect the battery ground cable and clean the contacts in the voltage regulators., Most electrical problems are poor ground . The 53 Buick should not be too problematic because it is a 12 v system Yes, that was the shocking part. Thought the 53 is safe but same thing as in my 6 V cars Link to comment Share on other sites More sharing options...
EmTee Posted August 29, 2022 Share Posted August 29, 2022 To determine whether the problem is the generator or the regulator, disconnect the IGN terminal from the regulator to disable it. Start the car and use a jumper wire to apply 6V directly to the field terminal (F) on the generator. If the ammeter shows a charge then the generator is working and the issue is the regulator. If the generator is not charging then the problem is with the generator. Link to comment Share on other sites More sharing options...
Rusty_OToole Posted August 29, 2022 Share Posted August 29, 2022 If you want a generator to last use Oilite bearings and lubricate with 3 drops of synthetic motor oil at every oil change. This will practically eliminate bearing wear. Then, replace the brushes when they get worn down to where they are below the top of the brush holder. If there is supposed to be a metal band around the brush area make sure it is in place. If you do this the generator should last the life of the car with perhaps one rebuild around the 60,000 mile mark. Link to comment Share on other sites More sharing options...
Frank DuVal Posted August 29, 2022 Share Posted August 29, 2022 On 8/26/2022 at 11:08 PM, dodge28 said: Hold the assembly in a vise, ground one battery cable to the vice and touch the other battery cable to the field. No! Touch the Armature terminal. If there is both a Firld and Armature terminal only the Armature terminal should be used for Motoring a generator. Awaiting others to say a particular generator is different 3 hours ago, EmTee said: Start the car and use a jumper wire to apply 6V directly to the field terminal (F) on the generator. Depends on if it is an A or B circuit generator. Typical GM generator systems are A circuit and you Ground the Field terminal to maximize generator output! See the shop manual for the particular car one is working on. Putting hot to a field terminal on an A circuit generator field will hurt both the generator and voltage regulator. Link to comment Share on other sites More sharing options...
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