NHC250 alternator pulley loose, throwing belts!

[98G]

Why would the shaft get hot?

I'm not doubting you, just wondering how. .

 

[M35A2-AZ]

I think I would replace the Alt., I'm thinking the shift will brake off in time.

 

[73m819]

Why would the shaft get hot?

I'm not doubting you, just wondering how. .

From the pulley working on the shaft , from the gouge making.

 

[sed6]

She might not be charging

I appreciate the input so far guys. So I finally got around to testing my alternator output and it's low. 24.4v, 22.1v with the lights on as the TM says. The TM says to remove the hex plug and turn the adjusting screw ccw to increase the output volts to 27.8 to 28.2v. Adjusting the screw either way had no noticeable effect on the volts. What say ye, bad alternator?

 

[jonesal]

Regulator. Check the large pile resistor and see if it phused it's guts out. If so. $5 fix. If not, new regulators are reasonable and abundant.

Al Jones
M923

 

[The HUlk]

While I have your attention, what's the small wire here do?

I believe the small wire is either a voltage reference which controls how much energy is output from the alternator, or a signal to the protective control box which indicates the engine is running so the starter can not be engaged. Knowing the wire number would help to understand it's function.

These alternators are notorious for going bad, being expensive to replace, and causing other problems along the way. I replaced mine with a civy unit and am glad I did. Details are here...

http://www.steelsoldiers.com/showthread.php?146113-M931A1-losing-magic-smoke&highlight=

 

[sed6]

Regulator. Check the large pile resistor and see if it phused it's guts out. If so. $5 fix. If not, new regulators are reasonable and abundant.

Al Jones
M923

Point me to this?

 

[jonesal]

The resistor is usually gold in color with fins in the longitudinal direction, about 1.5 to 2 inches in length. You'll see one of the black ends have pushed out if it went south. It's held into place with screws so you'll have to unsolder the ends to unmount it. I get the resistors from Israel or off eBay for $5. I have repaired 3 regulators this way. That being said in EVERY case, the generator baked the regulator because I had other problems on the vehicle like a bare wire, a miswire, etc. So although these units have a bad reputation, in my opinion, a lot has to do with other problems that manifest itself in cooking the regulator/generator. Hence, your pulley issue may have cracked a brush holder, rubbed through an internal wire, etc. requiring complete disassembly to properly diagnose. If the regulator faults (in a certain way) these units can run wide open and will catch fire. Repair parts are plentiful and I like working on electrical assemblies so I consider these units a reasonable one to repair. I consider a regulator a must-have spare part to carry in my onboard parts stash (like a PCB, compressor regulator, etc.). It takes minimal time to swap out to be back on the road.

I'll reiterate that your rotor shaft is beyond useable and you are gambling with being stranded on the road with a fist sized hole in your radiator making the cost of a generator repair pale in comparison to that.

Good luck,
Al Jones
M923 and other MVs

 

[sed6]

Great description, thank you! So $50 for a rotor, $25 for a pulley, I'm half way to a new clone setup right there and that doesn't count resistors or anything else that's gone wrong. Smart money says go clone, along with almost every member here. I'm thrifty but not stupid, so I'll go clone. Anyone want to buy my old alt, maybe I can recover a few dollars there? Thanks all for the input!

 

[74M35A2]

Chinese Delco clone can be had for $89. Genuine used but functional Delco could be had off eBay for nearly same price. Al Jones makes some good points, but you have multiple things wrong with yours, and replacing it entirely fixes all of it in a single swoop.