2007 Honda Pilot EX Alternator and Brushes Issue

[maverickfhs]

So I have a 2007 Honda Pilot EX, started the car today and battery light was solid on - checked the voltage and it was showing 14.XX.

Alternator sound was different and producing a slight burning smell.

Turned the car off, started back again this time voltage was fluctuating and still battery light was solid.

Removed the alternator and took it to a parts shop for bench test, they said it is a bad alternator.

Just now I pulled the brushes and they are completely worn, can it be just brushes or one of the diode is bad? Can I test the diodes?

Would anyone please know the part number for brushes? Checked on rockauto and not seeing it. It is a Honda/Denso alternator.

Thank you for the help.

 

[ctechbob]

I've bought parts from these folks before. They usually have most everything you need:

Parts Assistance

Premium quality alternator parts, alternator repair kits, starter parts and starter rebuild kits wholesale.

www.aspwholesale.com

Should be a link straight to your model. Click the 'Parts List' for a breakdown.

ALTERNATOR

Premium quality alternator parts, alternator repair kits, starter parts and starter rebuild kits wholesale.

www.aspwholesale.com

 

[Dave9]

Considering it is (assuming the factory part) now 15 years old, I'd just get a whole rebuild kit.

 

[spackard]

I can test the diodes by ear, tuning to a low frequency AM that's not in use and listening.
You need an oscilloscope, or a meter that measures percent distortion, and neither are cheap. Diodes are $40. If you don't run any aftermarket loads and are quick to change out batteries when they go bad I'd bet your diodes are still good.

 

[maverickfhs]

I can test the diodes by ear, tuning to a low frequency AM that's not in use and listening.
You need an oscilloscope, or a meter that measures percent distortion, and neither are cheap. Diodes are $40. If you don't run any aftermarket loads and are quick to change out batteries when they go bad I'd bet your diodes are still good.

No aftermarket loads and car is not a daily driver either.

Anyway I can use a multimeter to test the diodes bridge?

 

[spackard]

> Anyway I can use a multimeter to test the diodes bridge?

My feeling is no. I looked up the alternator for you car. It's an integrated diode bridge, so 6 diodes in a sandwich inside the alternator.

One cheap way to test is remove from car and take to auto parts store for a free bench test. Requires removal.

One method that doesn't require removal: if you have incadescent headlights you can shine them at a house or garage door and look for light dimming momentarily at warm idle maybe around 3 times per second.

 

[maverickfhs]

Tested diodes and they were burnt and shorted out, so after all brushes were super low and diodes were bad too.

 

[brianl703]

I can test the diodes by ear, tuning to a low frequency AM that's not in use and listening.
You need an oscilloscope, or a meter that measures percent distortion, and neither are cheap. Diodes are $40. If you don't run any aftermarket loads and are quick to change out batteries when they go bad I'd bet your diodes are still good.

Never tried it, but I bet a cheap wired telephone (or a butt/linesman's set) connected across the battery would reveal if the diodes are bad. You'd hear it as a whine.

I have used a telephone to check if filter capacitors are bad in power supplies...you'll hear the 60Hz buzz if they are.

 

[meep]

I’ll bet the arcing from intermittent brush contact killed the diodes. Diodes are probably rated to 60V and can’t handle the inductive pulse every time the connection dropped (which is how you get enough push to create a spark). The slip rings therefore likely could use a light buffing with emory cloth, but not enough to remove material in an inconsistent manner. ?