alternator diode
Advanced
Joined: Dec 2006
Posts: 72
Likes: 0
I have, a few times, replaced the diode bank and in all cases it corrected the problem. This was in the 70's and I have not tried this recently. I also remember when a friend started working at the Ford dealership and when I stopped in for a short visit I noticed the work benches were full of bad rotors. My diode replacements were all Chevy. If you can get a megger to test rotor and stator to verify insulation I would try the diodes.
Team Owner
Joined: May 2000
Posts: 53,716
Likes: 5,609
From: Plantation Florida USAF(Retired) 1966-1990
U.S. Air Force
St. Jude Donor '05 thru '26
NCM Sinkhole Donor
When I had my C4, the diode seems to go bad, and since I chromed my alternator I just kept changing them. They seem to go bad every 20,000 miles for some reason on my 89.
Team Owner
Joined: Sep 2003
Posts: 25,383
Likes: 2,736
Your alternator should be or is likely the CS130 and the rectifier is sometimes replaced "singularly" but I don't know why if you were going to the aggravation of removal and disassembly anyway you wouldn't do the brushes/holder assembly. Bearings maybe pass on but if it's original and 78K and you do your own services why not? There are premium rectifiers out there and there's also very inexpensive product. Which? Sounds like maybe you're wanting to "cheap-out"!
The 70's product that "net_coma" mentions were SI series and had bridge/rectifiers and diode-triode by description and a general repair consisted of "both" plus whatever.
The 70's product that "net_coma" mentions were SI series and had bridge/rectifiers and diode-triode by description and a general repair consisted of "both" plus whatever.
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
Many things can cause an alternator to fail.. A single Diode will not not cause an total failure, there are two Diodes per "Y" leg, one + and, one - for a total of 6. But if you loose one Diode per leg, then you will see a total failure, or a bad Stator, regulator, brush's, etc.. basically the alternator need to be disasembled and tested..
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
This makes sense.. Chrome acts like a thermal blanket, it doesn't dissapate heat nearly as well as an aluminum surface..
Team Owner
Joined: Sep 2003
Posts: 25,383
Likes: 2,736
In your hand the alternator is just a CS130 - Corvette means nothing!
Last edited by WVZR-1; Sep 28, 2013 at 02:41 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Instructor
Joined: Mar 2013
Posts: 149
Likes: 2
From: Long Island NY
You should give it a full rebuild by someone who knows how, but if you want to play here's some info and links that may help:
http://www.pirate4x4.com/tech/billav...2/#performance
http://www.pirate4x4.com/tech/billav...2/#performance
Team Owner
Joined: Sep 2003
Posts: 25,383
Likes: 2,736
Just maybe more difficult to find. If you check with a large fleet in the area or maybe a municipality they might offer up a shop that they use. The shops your looking for don't advertise, they're as busy as they want or need to be. Where are you located?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
I have fixed two alternators myself (and replaced a few).
The first one was on a '78 Corvette I used to own. I fixed it by replacing the voltage regulator module.
The second one was the one that's on my '86 now. It's a lifetime unit from O'Reilly. After ( had it for about 5 years it became intermittent. Sometimes it would just stop charging for no apparent reason. A minute later it would go back to working. I took it apart, cleaned everything, and put it back together. It's been fine for a year or so since then.
The first one was on a '78 Corvette I used to own. I fixed it by replacing the voltage regulator module.
The second one was the one that's on my '86 now. It's a lifetime unit from O'Reilly. After ( had it for about 5 years it became intermittent. Sometimes it would just stop charging for no apparent reason. A minute later it would go back to working. I took it apart, cleaned everything, and put it back together. It's been fine for a year or so since then.
Team Owner
Joined: Sep 2003
Posts: 25,383
Likes: 2,736
OE I believe should be 105A - K68
Thread Starter
Racer
Joined: May 2012
Posts: 269
Likes: 0
there is the remains of a sticker that was on bottom of the unit. i`ve seen this on recon units. there is corossion on the wires from coil to the rectifier . not even gonna open it up. i`ve replaced diodes on these things before and they worked. not taking chances with this one. i don`t need a breakdown in the middle of nowhere. there are no marks on this one anywhere.