ALTERNATOR REBUILD
10-02-2008, 01:49 PM
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ALTERNATOR REBUILD
I thought I would post my last (just finished) project was gutting/completely restoring the original Denso alternator in my '94. The headlights were getting "tweaky", and the bearings were starting to get sluggish. Denso alternators are known to run with toast bearings/brushes long before they actually go into failure.
The truth is to do it right, with TOP QUALITY parts costs more than a cheap rebuild, but should last 3-5 times longer. Here are a few notes-
When you have the case cracked open, take a Dremmel, or other HS small rotary tool, and using a felt-pad and fine grit polishing compound POLISH the bearing chases. They will have some corrosion, and if you do this, with the help of a LITTLE tune-up grease smeared to the insides of the bearing chases and outside edges of the bearing the bearings will press in VERY easily with a home-made press of flat steel/sockets/a large clamp.
You should plan (for extra long life) to replace ALL the internal parts except the rotor, if you soak it in electrical solvent to clean it up, then bench-test it for proper function (in any good manual). Also soak/scrub the coils.
Internal parts include front/rear bearings, the rectifier (AC to DC), the regulator (controls max voltage output), the brush housing, and various internal wave washers, gaskets and electrical bushings. Get a GOOD schematic off Majestic Honda to study the parts. Be sure to buy the internal small bushings/rubber washers/wire bushings also.
If you shop the net, you can find sources for a good, but cheaper, rectifiers. This is the part that "breaks the bank", the ONE part the rebuilders almost NEVER replace. They usually 1) clean the casing 2) replace bearings 3) install a cheap brush-set and regulator 4) use cheap hardware/bushings. Almost any cheap rebuild "runs" for 3-5 years until the RECTIFIER fails (first rebuild), then will be rebuild again with all the same cheap parts and a cheap rectifier.
resources- hondaautomotiveparts.com
waiglobal.com
wai-wetherill.com/products
acalternator.com/supply.htm
I found a local alternator store where the owner was willing to buy the parts for me, for a small fee, he rebuilds alternators and starters. I used all Denso OEM parts (especially the BEARINGS) and went with AM parts for the others. Next time I would probably go entirely OEM EXCEPT for the RECTIFIER, which Honda parts dealers hold onto as a "sacred cash cow". There's ALWAYS ONE PART Honda skins you on!
Except for MASSIVE bearing failure, rotors are RARELY damaged. I took mine to a machine-shop, and for $10 they took 1/1000 off the rotor poles to clean the brush-bearing faces.
I also chucked a 1/4" wide med wire brush into my LARGE Makita hammer/drill, and on HS drill setting completely buffed the entire casing, also easily done on a brush on a bench-grinder. How it shines!
A few notes- when I dropped the rotor into the end bearing/shell, it would not spin. The guy who sold me the parts checked it out- the BOTTOM bearing case cover was BARELY off, even set all the way down with the screws tightened. It was "catching" the end cooling fins. He loosened the screws, moved it around just a tiny, tiny bit, voila! The rotor spun free.
The rectifier mounted fine, but where the regulator sets right up against it a POURING-FLAW in the rec case (a "fin" sticking out") kept the regulator mounting tabs from aligning right. No prob- up on the "fine" grinder, cut the fin back, paint with some nearly matching paint I had, the reg dropped right into place and nestled right up to the reg housing.
Now I go to drop in the brush housing, and its mounting lugs/fins are slightly "off"- their shells are "fatter", and one is angled just a bit off to fit correctly. No prob-onto the FINE wheely, barely trim about 1/32 off the outside tabs, barely tweak one with a large linemans pliers, it dropped right in and fit perfectly.
Due to impending engine build, I installed an UR lightweight/polished pully. A NOTE here- the Honda OEM "washer-nut" sits down inside an inside chase at the front of the pulley, with around 3/16 clearance to the upward slanting pulley walls.
NOW- torquing down an OEM washernut onto ALUMINUM? Be careful! To "spread" the force of the nut out on the pulley, I bought a 7/16 ID polished zirc washer that almost fit the ENTIRE inside chase. It was just barely too large (about 1/16"), so I spun it on the fine grinder to drop the diameter about 1/16 per side. It dropped inot the cone-impression PERFECTLY, and protected the soft aluminum at final torquing. It also stops the OEM bolt form "digging" into the aluminum, making future removel VERY difficult if ANY corrosion starts.
Slapped it in, then the PS pump (soon to be gutted/rebuilt), fired the engine, and the finsihed unit is INCREDIBLY smooth and quiet, much quieter than ANY rebuilt alt I have ever dropped in. And, personally, I am SICK and TIRED of 'partially rebuilt' parts failing after 3-5 years, if you haven't been around a while, it's PLANNED that way for 2nd and later owners, an ENDLESS stream of revenue!
A perfect 15.2V under no load, dropped to 12.2 under headlight load, then came back up. No more "headlight tweaking" as the very old bearings and brushes try to work.
Anyway, I thought I would post this. Most pics would be useless- many of these parts are SMALL and would be very hard to see in a pic. You are better off studying a blowup schematic of your unit. If you are a good mechanic, and have the time, this type self-rebuild will outlast ANY rebuild 3-5X, IF you buy good AM or OEM parts and not "cheapos".
"Warrantees" are a joke, they just bank money to cover the "failed units", IF you have the RECEIPT from 2-5 years ago! They'll just give you another unit, rebuilt in Mexico or Asia, where the "one bad inner part" was replaced, with CHEAP bearings, then shipped out for sale. This original is 14+ years old, and should go for another 14+ years. Study, take your time, DONT buy cheap parts!
Just the way I build ALL my cars. The suspension and entire brake system on this car were rebuilt with this same attention to detail. The entire brake system, rebuilt apx. 3 years ago (including ALL hydraulics and SS lines), has used 0 drops of fluid (mostly Honda OEM). The suspension was done so carefully 2.5 years ago that after 20K miles there is ZERO wear on any of the tires (ES bushings EVERYWHERE, HK springs, Tokiko struts, Ingalls camber-arms rear).
If you do it slowly, with precision, and with good parts, it can last 20+ years. If you go "cheap" for parts, and often use a hammer when working (mine is rusty) and do typical 'line-mechanic" quality work (hurry/hurry/hurry) you will get a half-assed product that will cause problems, headaches, and wear out FAST. For some advice, the ONLY problems I have EVER had on this car was when "mechanics" touched it. A few good ones are left, but a dying breed. I never let one touch this car now. Wrenchy
The truth is to do it right, with TOP QUALITY parts costs more than a cheap rebuild, but should last 3-5 times longer. Here are a few notes-
When you have the case cracked open, take a Dremmel, or other HS small rotary tool, and using a felt-pad and fine grit polishing compound POLISH the bearing chases. They will have some corrosion, and if you do this, with the help of a LITTLE tune-up grease smeared to the insides of the bearing chases and outside edges of the bearing the bearings will press in VERY easily with a home-made press of flat steel/sockets/a large clamp.
You should plan (for extra long life) to replace ALL the internal parts except the rotor, if you soak it in electrical solvent to clean it up, then bench-test it for proper function (in any good manual). Also soak/scrub the coils.
Internal parts include front/rear bearings, the rectifier (AC to DC), the regulator (controls max voltage output), the brush housing, and various internal wave washers, gaskets and electrical bushings. Get a GOOD schematic off Majestic Honda to study the parts. Be sure to buy the internal small bushings/rubber washers/wire bushings also.
If you shop the net, you can find sources for a good, but cheaper, rectifiers. This is the part that "breaks the bank", the ONE part the rebuilders almost NEVER replace. They usually 1) clean the casing 2) replace bearings 3) install a cheap brush-set and regulator 4) use cheap hardware/bushings. Almost any cheap rebuild "runs" for 3-5 years until the RECTIFIER fails (first rebuild), then will be rebuild again with all the same cheap parts and a cheap rectifier.
resources- hondaautomotiveparts.com
waiglobal.com
wai-wetherill.com/products
acalternator.com/supply.htm
I found a local alternator store where the owner was willing to buy the parts for me, for a small fee, he rebuilds alternators and starters. I used all Denso OEM parts (especially the BEARINGS) and went with AM parts for the others. Next time I would probably go entirely OEM EXCEPT for the RECTIFIER, which Honda parts dealers hold onto as a "sacred cash cow". There's ALWAYS ONE PART Honda skins you on!
Except for MASSIVE bearing failure, rotors are RARELY damaged. I took mine to a machine-shop, and for $10 they took 1/1000 off the rotor poles to clean the brush-bearing faces.
I also chucked a 1/4" wide med wire brush into my LARGE Makita hammer/drill, and on HS drill setting completely buffed the entire casing, also easily done on a brush on a bench-grinder. How it shines!
A few notes- when I dropped the rotor into the end bearing/shell, it would not spin. The guy who sold me the parts checked it out- the BOTTOM bearing case cover was BARELY off, even set all the way down with the screws tightened. It was "catching" the end cooling fins. He loosened the screws, moved it around just a tiny, tiny bit, voila! The rotor spun free.
The rectifier mounted fine, but where the regulator sets right up against it a POURING-FLAW in the rec case (a "fin" sticking out") kept the regulator mounting tabs from aligning right. No prob- up on the "fine" grinder, cut the fin back, paint with some nearly matching paint I had, the reg dropped right into place and nestled right up to the reg housing.
Now I go to drop in the brush housing, and its mounting lugs/fins are slightly "off"- their shells are "fatter", and one is angled just a bit off to fit correctly. No prob-onto the FINE wheely, barely trim about 1/32 off the outside tabs, barely tweak one with a large linemans pliers, it dropped right in and fit perfectly.
Due to impending engine build, I installed an UR lightweight/polished pully. A NOTE here- the Honda OEM "washer-nut" sits down inside an inside chase at the front of the pulley, with around 3/16 clearance to the upward slanting pulley walls.
NOW- torquing down an OEM washernut onto ALUMINUM? Be careful! To "spread" the force of the nut out on the pulley, I bought a 7/16 ID polished zirc washer that almost fit the ENTIRE inside chase. It was just barely too large (about 1/16"), so I spun it on the fine grinder to drop the diameter about 1/16 per side. It dropped inot the cone-impression PERFECTLY, and protected the soft aluminum at final torquing. It also stops the OEM bolt form "digging" into the aluminum, making future removel VERY difficult if ANY corrosion starts.
Slapped it in, then the PS pump (soon to be gutted/rebuilt), fired the engine, and the finsihed unit is INCREDIBLY smooth and quiet, much quieter than ANY rebuilt alt I have ever dropped in. And, personally, I am SICK and TIRED of 'partially rebuilt' parts failing after 3-5 years, if you haven't been around a while, it's PLANNED that way for 2nd and later owners, an ENDLESS stream of revenue!
A perfect 15.2V under no load, dropped to 12.2 under headlight load, then came back up. No more "headlight tweaking" as the very old bearings and brushes try to work.
Anyway, I thought I would post this. Most pics would be useless- many of these parts are SMALL and would be very hard to see in a pic. You are better off studying a blowup schematic of your unit. If you are a good mechanic, and have the time, this type self-rebuild will outlast ANY rebuild 3-5X, IF you buy good AM or OEM parts and not "cheapos".
"Warrantees" are a joke, they just bank money to cover the "failed units", IF you have the RECEIPT from 2-5 years ago! They'll just give you another unit, rebuilt in Mexico or Asia, where the "one bad inner part" was replaced, with CHEAP bearings, then shipped out for sale. This original is 14+ years old, and should go for another 14+ years. Study, take your time, DONT buy cheap parts!
Just the way I build ALL my cars. The suspension and entire brake system on this car were rebuilt with this same attention to detail. The entire brake system, rebuilt apx. 3 years ago (including ALL hydraulics and SS lines), has used 0 drops of fluid (mostly Honda OEM). The suspension was done so carefully 2.5 years ago that after 20K miles there is ZERO wear on any of the tires (ES bushings EVERYWHERE, HK springs, Tokiko struts, Ingalls camber-arms rear).
If you do it slowly, with precision, and with good parts, it can last 20+ years. If you go "cheap" for parts, and often use a hammer when working (mine is rusty) and do typical 'line-mechanic" quality work (hurry/hurry/hurry) you will get a half-assed product that will cause problems, headaches, and wear out FAST. For some advice, the ONLY problems I have EVER had on this car was when "mechanics" touched it. A few good ones are left, but a dying breed. I never let one touch this car now. Wrenchy
10-02-2008, 02:01 PM
#3
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Re: (TheMuffinMan)
Sweet write up, very detailed. I like!
I actually just cracked mine open and completely stripped it last night.
Some really good tips on the rebuild.
Thanks Wrenchy
I actually just cracked mine open and completely stripped it last night.
Some really good tips on the rebuild.
Thanks Wrenchy
10-03-2008, 08:07 PM
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Re: (GhostAccord)
Hey, Muffinman. Long time, no talk.
When done, I had about $180 into the rebuild. But you have to consider a few facts
1) I saw a few "new" units, with "all new parts" for about $150-180. Let's argue I paid 50% markup off wholesale on my parts. That would mean the parts, hard-core wholesale (what a "builder" would pay) were $90.
Now, HOW can a builder of "new" units use the same $90 high-quality parts I did, but then have to also pay for a "new" pulley (maybe $15), a new rotor (maybe $20), new shell parts (maybe $20), and new windings (maybe $15). They would have $160 just in parts, BEFORE labor and shipping!! They would make 0% profit!
The rebuilder I bought the parts from explained what I already knew- the unit IS "NEW" (all parts), but the QUALITY of the parts is very low quality. They have to put every single part out to bid, absolutely 'lowest bidder'. So the end product is FAR below the OEM Denso quality.
As I said, the market for AM alts, PS pumps and such is VISCIOUS. The lower priced units are made of very, very low quality "new" parts, or the rebuilder strips each unit, bench tests and REUSES almost all the internals (new brushes, usually new regulator, new bearings, new gaskets), but the end rebuild is mostly OEM parts that are "still working" with AM cheap parts added on. This is the ONLY way they can make ANY money, and the profit margins are SLIM.
The rebuilder I bought parts from said he sees a LOT of "rebuilt" or "new" 2-3 year old units with re-failed regulators (cheap parts) or failed rectifiers (rarely replaced in 'rebuilds').
The bottom line is I have a unit I know has ALL NEW OEM quality parts, except the rotor (re-used), so there is an excellent chance it will last as long as the Denso OEM unit. I would rather spend a little extra $$$ and time to KNOW the unit has all new, high quality parts.
In the past 30 years I have noticed "rebuilds" are failing at a higher rate, and faster, than they used to. I myself have had a few alts, PS pumps, and other "rebuilt" units fail 2-3 years after install. I'm not alone-mechanics I talk to are having the same problems. No more- I have the time now to REBUILD, so I do!
MOST AM parts ARE NOT the same quality as Honda suppliers used OEM, but they are what is going into the "rebuilds". The "rebuild" or replacement "new" market is so competitive the profits have to come from SOMEWHERE- it's coming from sub-par quality parts. Wrenchy
When done, I had about $180 into the rebuild. But you have to consider a few facts
1) I saw a few "new" units, with "all new parts" for about $150-180. Let's argue I paid 50% markup off wholesale on my parts. That would mean the parts, hard-core wholesale (what a "builder" would pay) were $90.
Now, HOW can a builder of "new" units use the same $90 high-quality parts I did, but then have to also pay for a "new" pulley (maybe $15), a new rotor (maybe $20), new shell parts (maybe $20), and new windings (maybe $15). They would have $160 just in parts, BEFORE labor and shipping!! They would make 0% profit!
The rebuilder I bought the parts from explained what I already knew- the unit IS "NEW" (all parts), but the QUALITY of the parts is very low quality. They have to put every single part out to bid, absolutely 'lowest bidder'. So the end product is FAR below the OEM Denso quality.
As I said, the market for AM alts, PS pumps and such is VISCIOUS. The lower priced units are made of very, very low quality "new" parts, or the rebuilder strips each unit, bench tests and REUSES almost all the internals (new brushes, usually new regulator, new bearings, new gaskets), but the end rebuild is mostly OEM parts that are "still working" with AM cheap parts added on. This is the ONLY way they can make ANY money, and the profit margins are SLIM.
The rebuilder I bought parts from said he sees a LOT of "rebuilt" or "new" 2-3 year old units with re-failed regulators (cheap parts) or failed rectifiers (rarely replaced in 'rebuilds').
The bottom line is I have a unit I know has ALL NEW OEM quality parts, except the rotor (re-used), so there is an excellent chance it will last as long as the Denso OEM unit. I would rather spend a little extra $$$ and time to KNOW the unit has all new, high quality parts.
In the past 30 years I have noticed "rebuilds" are failing at a higher rate, and faster, than they used to. I myself have had a few alts, PS pumps, and other "rebuilt" units fail 2-3 years after install. I'm not alone-mechanics I talk to are having the same problems. No more- I have the time now to REBUILD, so I do!
MOST AM parts ARE NOT the same quality as Honda suppliers used OEM, but they are what is going into the "rebuilds". The "rebuild" or replacement "new" market is so competitive the profits have to come from SOMEWHERE- it's coming from sub-par quality parts. Wrenchy
10-03-2008, 08:22 PM
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Re: (wrenchy)
GHOST- Note the problem with the internal cooling-fins clearing the bearing retainer-case inside the shell.
At first it seemed the outside face of the rotor was brushing the windings (it was), but after the bearing-case was VERY finely reset, allowing the fins to "clear", the center-axis of the rotor itself was reset, stopping the dragging of the rotor-face on the windings. We're talking a misalignment of the bearing case by maybe only 1/1000 of an inch, that's how tight the internal tolerances/clearances are!
One of those cases where one SMALL problem causes another, with the second problem appearing to be the real problem. Use good parts, take your time, the new unit should outlast any 'market' unit 2-5X. Wrenchy
At first it seemed the outside face of the rotor was brushing the windings (it was), but after the bearing-case was VERY finely reset, allowing the fins to "clear", the center-axis of the rotor itself was reset, stopping the dragging of the rotor-face on the windings. We're talking a misalignment of the bearing case by maybe only 1/1000 of an inch, that's how tight the internal tolerances/clearances are!
One of those cases where one SMALL problem causes another, with the second problem appearing to be the real problem. Use good parts, take your time, the new unit should outlast any 'market' unit 2-5X. Wrenchy
11-09-2008, 08:11 AM
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Re: (wrenchy)
Thanks for this thread, sir. I noticed this thread is fairly new, and I still amaze myself, with how much info I can find here on H-T, even though I sold my civic over 2 years ago, and I've been with H-T since 02! This time, I was looking for info about my lady's 02 accord alternator, and you've researched some pretty impressive info on alternators in general, and I plan on buying a rebuilt one for her, for the time being, while I take the original one out, and rebuild it back to OEM spec. Her friend, has the same accord, and she had to replace her alternator, and it is so loud, I am sure the mechanic half-assed the rebuild, and told her it's normal to have that sound in rebuilt alternators, and to his knowledge it's true, because like you say, they are poorly built, and the minor details are overlooked in the rebuilding, and so that is why the mechanic said such a thing. Anyways, I honestly think this should go in the FAQ section! Thanks again 
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05-23-2011, 08:19 AM
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Re: ALTERNATOR REBUILD
wrenchy, where did you get your regulator? Did you build your own to make it sit at 15v, or did somebody build it for you custom? I cant find any that will output more than 14.4. I want a new one for this backup alt I have (the regulator is tore up on it) and i want to have my voltage about 14.6-15v.
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