so in january...i was getting a light glowy alternator light.
so i replaced the voltage regulator. this seemed to cure all ills.
the brushes on the old reg were verry worn down..so i suspected this was said culprit. alas...a couple days ago light is back..this time pretty much solid red the whole time im driving. is it time to buy a new alternator? rather be safe than sorry


minsk
1982 300Td // Mathilda // 150k on her


edit: brand new battery. also bought a new adjustment bolt for the alternator...belts are new and nice and tight

edit 2: ok put the multi meter on the battery. 12.5 at with key on. 12.13 with clicked to on. 12.65 with motor running and gassing it.
seems as thought the alternator is barely working am i correct?

Hard to say for sure without more testing.

Do you have a multimeter? If not they are a good investment. It would be helpful to know what voltage the battery is at with the car off vs. idling vs. revving up.

The battery light in the cluster lights up when there is a difference between battery voltage and alternator voltage. This can be caused by a deceased alternator but it's not the only possible problem. It may be as simple as a bad connection, or a loose belt.

If you have a nearby auto parts store they will usually test your charging system for free. It can help narrow it down.

Don't rule out that the voltage regulator you installed has gone bad already. Quality on these parts is not what it used to be. A friend had his fail on him after 1 year despite the brushes passing visual inspection. It failed suddenly while on a group cruise up to Phoenix. Lead to a no-charge situation. It had some sort of internal failure.

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1979 300D 040 Black on Black - 1985 300D Maaco job (sadly sprayed over 199 Black Pearl Metallic) on Palamino

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Before replacing the alternator, clean the slip rings. Do this by removing the VR, which will expose the rings. Hold a solvent soaked cloth against the rings while turning the alternator. Put the VR back and see if that does it.

err...what are slip rings...are these the things things the brushes ride on inside the alternator

Yes. The carbon that wears off the brushes coats the slip rings, and doesn't conduct well.

any recommended alternators at FLAPS i have autozone, napa, and advanced

returned from FLAPS .
Regulator FAIL
Diode FAIL
it also had a cracked case
the regulator was new
upgraded to a 65amp Duralast
they dint have bosch
tho it does have a life time warranty

$122.00

oh well
better safe than sorry

Did you grab the old regulator for your parts box?

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

no i screwed up. long day.
edit: just realized i have to get the pulleys and washers off the old one.

If you had a diode fail, it will usually take out a new regulator in short order. For this reason, it is best to take VDC and VAC measurements with a multimeter before replacing the regulator. High VAC (above 100mVAC) indicates a bad diode.

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Sam

84 300SD 350K+ miles ( Blue Belle )

replaced the alternator today.
my tensioner bolt is broken however.
so i got it a tight as i could with out the long tensioner bolt.
the one that is broken is only a couple months old
obviously a bad weld on it. the man who i bought it from claimed it was OEM.
i dont remember the packaging.


question.
so the long tensioner part of the tension alternator bolt broke.
so i had a freind push down..cause belt tension on the belt...and tightened the bolt. mind you i dont have the tensioner part of the bolt connected. i torqued down the bolt pretty well. is this safe? i have like an 1.8 in play in the belts when i push on it. the alternator works very well..battery light goes off as should etc. im getting 13.9v when engine is running now. also i upgraded to the 65amp alt. sorry for the winded message

There is a fix for that Tensioner Bolt.

http://www.peachparts.com/shopforum/diesel-discussion/290803-stuck-v-belts-alternator-bolts-frozen-tension-bolt-broken.html

Post# 24 shows a picture using an "EYE Bolt".


Charlie

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1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

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Your problem is corrosion in the wiring. Look for green where it should be copper red. Also look at the chassis ground, and make sure it is solid.

Any green in the wiring (most of the time + battery post) causes resistance in teh circuit. The electrons travel on the outside of copper wire, when the wire is corroded, the corrosion adds resistance to the path.
This resistance causes the alternator to put out a higher voltage (to charge the battery) this voltage could get high enough to the point that lights start to burn out frequently.

Check for Green,,,

Baking soda & water remove green, (so does Coke)

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