Alternator Brush Replacement

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JoeIsuzu
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Location: Germantown (next to Elvistown), TN
Isuzu vehicle(s): Original owner, '83 LS Diesel, 5-spd, 2wd, Long Bed, restoration in progress!

Alternator Brush Replacement

Post by JoeIsuzu »

This article is compiled from instructions from Andy (puttputtinpup), StevePT, Jerry (JLEMOND), and finally, from my experience at doing this job.

Parts and supplies needed:
  • New brushes: Advance Auto, Brush Holder Assembly (currently $4.49, but subject to change). My local store didn't have these in stock on a Saturday afternoon, but got them the next day (a Sunday) as a "PDQ" order at no extra charge.
    Update, 5/29/2012: Tim "Seer7" found a supplier who sells the brushes with the leads already soldered on. That eliminates the need for soldering, and makes it about a 10-minute job.
  • Stubby Phillips head screwdriver
  • Box-end or socket wrench for the coverplate bolts. I'm fairly certain it's metric, but I didn't have a small enough metric wrench. A standard 9/32 worked fine without any slipping. The screwdriver wouldn't break them loose, but worked well once I get them loose.
  • Can of brake cleaner.
  • Drip pan.
  • Work light.
  • Soldering iron/solder/flux.
  • File or grinder to clean off any excess solder/wire from top of retainer clip.

Time required: If you're really good, 20-30 minutes. If you're being overly careful not to drop a screw into the alternator or burn yourself soldering, maybe an hour. If you drop the screw in...it depends on how much damage you do retrieving it.

The alternator brushes can be replaced without removing the alternator. If you have power steering, it's a little harder to get to, but it can be done. The intake baffle box is a little in the way. You could remove it or the entire air cleaner assembly, but I just used a stubby screwdriver and left everything on. The biggest challenge was NOT dropping the little screws into the inside of the alternator, as is my normal method of operation.

All the under-hood photos below are taken from the driver's side looking across the engine compartment (in case you're having trouble getting your bearings).

Looking on top of the alternator towards the back, you'll see a wire loom coming out of the alternator. There is a plate held down by two screws. The wiring goes in through the plate. Take those two screws out and remove the plate (see photo).
This photo shows the coverplate.  The wrench is on one of the two bolts that must be removed.
This photo shows the coverplate. The wrench is on one of the two bolts that must be removed.
Inside, you'll see two more screws, one holding each of the brushes. Be careful not to drop the little screws inside. The bushes are spring loaded. If they're worn badly, they shouldn't pop up much, if any. Take the brushes out, noting the orientation of the brushes--not just the retainers, but the brushes themselves. The brushes wear at an angle, and the new ones are ground off at a similar angle. You will want to put the new ones in oriented the same way as the old ones, which is long side toward the drivers side fenderwell on both brushes.
One brush has already been removed in this photo.  The second brush still has its retaining screw in place in the lower left side of the opening.
One brush has already been removed in this photo. The second brush still has its retaining screw in place in the lower left side of the opening.
After removing the brushes, Jerry (JLEMOND) recommends that you take the opportunity to clean out any debris. He says this will make a mess under the truck, so use a drip pan if that's an issue. Spray a can of brake cleaner into the openings (not carb cleaner, as it tends to leave a residue). Give it about 10 minutes to drip and dry before putting the new brushes in.

While it's drying out, if you bought the brushes without ends soldered on, now is a good time to transfer the ends to the new brushes. Andy (puttputtinpup) recommends that when soldering the cables back on the ends, try to get the length (the distance from the carbon to the metal connector) close to the originals. You will want the cable stopping the brush from wearing completely out, but rather leaving a small piece.
This shows the soldering.  The retainer tab is locked in the vise.  I threaded the wire through the small hole in the retainer, soldered, then clipped away the excess.
This shows the soldering. The retainer tab is locked in the vise. I threaded the wire through the small hole in the retainer, soldered, then clipped away the excess.
I recommend NOT putting the springs on until after you have soldered the connectors on.
This one shows a spring partially installed.  You just slip the wire into the spring, and either spin it or wrap the wire into the spring.
This one shows a spring partially installed. You just slip the wire into the spring, and either spin it or wrap the wire into the spring.
PupAlternatorBrushes_spring_replacement.jpg (44.81 KiB) Viewed 7170 times


Some have reported that they only needed to replace one brush, as they don't always wear at the same rate. Use your own judgment on this, it should be easy to tell when you compare the old ones to a new one. Replace the retainer screws (without dropping them into the alternator), replace the cover plate and screws, and you're done.

Added 12/07/2009, by popular demand:
The first time you move, remove, or replace your alternator, you REALLY need to replace the oil line that runs from the block to the vacuum pump on the back of the alternator. After sitting in one place for 20-25 years, it can break INSIDE without showing up on the outside. You can lose all your oil very quickly, and destroy your engine. Mine broke, and I was dangerously low before realizing it. And yes, I'd been warned, but for some reason I thought it wouldn't happen. :oops: Fortunately, no damage was done.

JLEMOND tries to keep "about 2 dozen" of these lines in stock, so he can get you one pretty quickly. Some owners have also gotten new lines custom made at motorcycle shops and hydraulic shops.

When replacing, be really careful not to overtighten, because the banjo bolts can easily be stretched and broken.

Added 01/11/10 by request from kraavdra: If you find that you need an alternator, here's a tip from smokey:
smokey wrote:...The great thing about the alternator is that it came with a NEW vac pump already on it and everything you need to hook it up you'll have too change a few things off your old one but that will be a no brainer on what to do. The part # is 14648 and the manufactor is Ultima Import and I got it from O'Reilly's just under 130.00 after core charge.
If anyone discovers this part number to be obsolete, please let me know.

I've deleted all replies to this post because this is a "How-to" article, and the replies were going off topic. If anyone wants to suggest improvements to this article, just send me a PM.

Jack
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