I suppose you can have TWO "good" junkyard alternators both suddenly fail though it seems kinda unlikely. For the price for a fresh rebuilt alternator ($40 or so) you might be ahead to get one instead of another junkyard unit.
However a healthy alternator will be ruined if the charge circuit (alternator BAT to ammeter to battery positive) goes open while it's charging - if even for an instant. Also if the sensing circuit (wiring to the #2 terminal) goes open while running. So I'd suggest double checking all wiring for good tight connections - including the battery cable terminals
---
As for determining exactly what's failed on a dead alternator here's a couple things to check:
1 - With the engine running at 1/2 throttle bypass the regulator by grounding shorting tab inside the back of the alternator. If it now charges hard the regulator has failed.
2 - If you have a VOM or DMM set the meter on the lowest ohms range. Now disconnect all wiring from the alternator and take a resistance reading between the BAT terminal and the case. Note the reading then reverse the meter probes and measure again.
A "good" reading is infinite resistance with the probes one way and very low resistance with the probes reversed.
Infinite ohms in both directions means an open circuit in either the stator or diode bridge. Low ohms in both directions is a shorted bridge. Only fix for either is to replace with new.
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]
Today's Featured Article - History of the Cockshutt Tractor - by Danny Bowes (Dsl). The son of a very successful Toronto and Brantford, Ontario merchant, and himself quite an entreprenuer, James G. Cockshutt opened a business called the Brantford Plow Works in 1877. In 1882, the business was incorporated to become the Cockshutt Plow Company. Along with quality built equipment, expedious demand and expansion made Cockshutt Plow Works the leader in the tillage tools sector of the farm equipment industry by the 1920's.
... [Read Article]
Latest Ad:
1964 I-H 140 tractor with cultivators and sidedresser. Starts and runs good. Asking 2650. CALL RON AT 502-319-1952
[More Ads]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
