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Old 02-28-2024, 11:50 AM   #1
72c20customcamper
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Alternator decoding

I’m thinking this is the original alternative for my 1968 part number 1100794 = 37a date code 7L8 I’m thinking that stands for 1967 December 8th am I off base ? I’m putting new bearings in it regardless it was charging but howling. I took it off the 68 stepside
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Old 02-28-2024, 12:20 PM   #2
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Re: Alternator decoding

Yes, it appears correct for your truck. 1968 307, 327 or 396 37amp.
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Old 02-28-2024, 12:38 PM   #3
72c20customcamper
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Re: Alternator decoding

Quote:
Originally Posted by too much stuff View Post
Yes, it appears correct for your truck. 1968 307, 327 or 396 37amp.
250 too?
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72 c20 custom camper Husky edition,
66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark
1969 AMX ,
1968 c20 stepside ,85 K20
1977 Suburban sold
68 anniversary.
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Old 02-28-2024, 01:11 PM   #4
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Re: Alternator decoding

Test your diodes while you have it apart. A bad diode will cause a noise similar to a brg.
The alt will still charge with an open diode but will have much lower output.

George
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Old 02-28-2024, 01:37 PM   #5
72c20customcamper
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Re: Alternator decoding

Quote:
Originally Posted by Wrenchbender Ret View Post
Test your diodes while you have it apart. A bad diode will cause a noise similar to a brg.
The alt will still charge with an open diode but will have much lower output.

George
Front bearing was toast was actually hard to turn the shaft . Rear wasn’t to bad but I replaced it to . Spins nicely now
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72 c20 custom camper Husky edition,
66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark
1969 AMX ,
1968 c20 stepside ,85 K20
1977 Suburban sold
68 anniversary.
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Old 02-28-2024, 03:36 PM   #6
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Re: Alternator decoding

I have a noisy one also. Can you elaborate a bit on the complexity of swapping out the bearings. Mine charges great but it is in need of new bearings for sure…thanks !
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Old 02-28-2024, 04:10 PM   #7
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Re: Alternator decoding

Quote:
Originally Posted by 72c20customcamper View Post
250 too?
Dec 8 of 67 is correct. My book only covers V-8, but may have been used on the 6 cyl also.
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67 gmc custom lwb dakota truck. Sold...And bought back
69 swb 4x4 project (in progress)
70 c-10 lwb texas truck
70 4x4/BB/bkts/posi/tach(retired)
70 swb (wifes)
70 jimmy camper
71 K-5 factory 2wd
71 cheyenne 4x4/tach/posi/ plow rig
71 Cheyenne20 BB, buckets, tach, tilt, 4 speed
72 jimmy CST wyoming rig
72 jimmy Colorado rig
72 lifted texas 4x4 3/4 ton burb
65 fury conv. 383/auto
65 chrysler 300 "L" 413 auto
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Old 02-28-2024, 04:26 PM   #8
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Re: Alternator decoding

Quote:
Originally Posted by 54blackhornet View Post
I have a noisy one also. Can you elaborate a bit on the complexity of swapping out the bearings. Mine charges great but it is in need of new bearings for sure…thanks !
Very easy front is held in with cover with three screws just falls out . The rear needs to be pressed out and in but it’s really a simple job you will need a piece of thin wire to hold the brush’s in I use a small finish nail you can see it in this picture
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72 c20 custom camper Husky edition,
66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark
1969 AMX ,
1968 c20 stepside ,85 K20
1977 Suburban sold
68 anniversary.
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Old 02-28-2024, 10:14 PM   #9
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Re: Alternator decoding

Nice work.

George
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