Thinking of rebuilding the alternator

Kestas

Staff member
Messages
13,863
Location
The Motor City
My winter car has 95K with an original alternator. I'm thinking of rebuilding the alternator when it's retired for the summer. It seems I can do it with the $50 kit from this web site. Alternator starter rebuild kits They have good video tutorials, and the pictures they show of the worn copper rings makes me think my alternator may be close to being consumed. The last time I though about doing both starter and alternator with another car, I thought too long and the started conked out and I had to do an emergency repair in 11°F weather. Checking rockauto, the alternator for my car varies from $80 for the inexpensive all the way to $250 for OEM. I've been stranded before more than once with a bad alternator. Is this a good plan? Has anyone done anything like this?
 
Messages
5,183
Location
NJ
What kind of car is it? My Rav4 still has the original alternator. Why fix what ain't broke unless you suspect your alternator has a short life span due to its design or lack use over the summer.
 
Messages
25,414
Location
Upstate NY
One of the things a rebuilder can do is to put the armature on a lathe and cut slightly where the brushes hit. Can you do that? How about the 6 diode bridge, will you replace that?
 

Kestas

Staff member
Thread starter
Messages
13,863
Location
The Motor City
This is for a 2001 Mercury Sable. The alternators reportedly last an average of 120K. I want to stay on the good side of the Bell curve. The voltage regulator is included with the kit. Would that include the diode bridge? I have easy access to a lathe. At the very least I'll have the luxury of time to be able to take it apart and assess the unit before tackling it.
 
Messages
4,063
Location
Central Virginia
My brother is probably one of the best shade tree mechanics that exists and he yelled at me for being lazy and buying a rebuilt alternator LOL. It was for a 1999 Jeep Cherokee 4.0 and the bearings seized up sometime during the summer (it was a winter car). I figured as hard as it was to get to I should get it right the first time but it def is a DIY job if you have the motivation and want to save a few bucks. I replaced diodes in an old Buick alternator a LONG time ago and IIRC they press out of the "bridge" and you can replace them individually.
 
Messages
9,028
Location
Marshfield , MA
Originally Posted By: Donald
One of the things a rebuilder can do is to put the armature on a lathe and cut slightly where the brushes hit. Can you do that? How about the 6 diode bridge, will you replace that?
Yah, I've seen starters and generators rebuilt. Sonny Oxner had an an electric thingy that tested windings on the armature by turning it into an electro-magnet. The lathe was driven by wide leather belts from a huge electric motor 30 feet away. You could probably turn an armature on a wood working lathe. Sonny used a tool to clean the gaps in the commutator. Bearings were repacked, bushing replaced and reamed to fit. brushes were replaced. In alternators, diodes were checked and resoldered. This was over 50 yrs ago. The rebuild kit for a 1 or 2 wire Delco alt. came with a new diode pack
 
Last edited:
Messages
36,108
Location
ME
I've fiddled around inside of Delco CS130s. The bearing is a common 6203 (?) and $2 on ebay. Sometimes the front and rear are clocked differently for different applications but they're otherwise identical inside. If you have a couple of them you can build a mongrel that works for you. I tried fiddling with the armature of a motorcycle starter motor, didn't end well. I would just change the diode bridge if necessary and the bearings and brushes.
 
Messages
6,639
Location
South Florida
I wouldn't touch it until it goes out. Which could be years and years from now. You might even sell the car before the alternator ever goes out. I have almost a million miles on the road without an alternator failure. My last alternator failure was probably 20 years ago.
 
Messages
9,922
Location
MA
Originally Posted By: Kestas
This is for a 2001 Mercury Sable. The alternators reportedly last an average of 120K. I want to stay on the good side of the Bell curve. The voltage regulator is included with the kit. Would that include the diode bridge? I have easy access to a lathe. At the very least I'll have the luxury of time to be able to take it apart and assess the unit before tackling it.
Which engine do you have? The duratec was a pain, but you could flip the alternator and get it out of the wheel well instead of dropping the subframe. The vulcan was easier to get at from the top. I went over 200k on the duratec engine and changed the alternator 3 times. I got one with a lifetime warranty from Autozone. I think the first one conked out at around the 100k mark and I think I changed the 2nd one at a bit under the 200k mark and then the 3rd one was just hopping that some glitches I was getting was just an electrical problem as the alternator was free and the mechanic only wanted $50 to toss it in. I think it was only a bit over $100 for the alternator. I did have them test it before I took it, lots of stories about how the reman ones are duds.
 
Messages
25,123
Location
MA, Mittelfranken.de
Originally Posted By: andyd
Sonny Oxner had an an electric thingy that tested windings on the armature by turning it into an electro-magnet. The lathe was driven by wide leather belts from a huge electric motor 30 feet away. You could probably turn an armature on a wood working lathe.
Years ago we had a small hand crank commutator lathe and a motor growler, both still worked fine despite being 25 yrs old then. The growler was a primitive yet very effective way of checking the armature winding's, checking the field is easy with a VOM. There was a big round soldering iron for replacing the commutator if necessary.
 
Messages
2,560
Location
wv
My alternator went out on my Suburban about a month ago while i was driving. I drove it about 20 miles with it dead. I could have.. If i made it home- a)Called the local starter/alternator rebuild shop to see what they had (they are usually about $50 with exchange). b)Called Junkyards- They are usually $25 c)Ordered online. What i did- My local NAPA had a new one for $150- they loaned me all the tools to do it and one of the guys helped me with the belt while i installed in the lot. If you have free time on your hands you can start looking at junkyards and probably find a shiny one that someone has replaced and put it in the trunk.
 
Originally Posted By: krismoriah72
If you have free time on your hands you can start looking at junkyards and probably find a shiny one that someone has replaced and put it in the trunk.
Steal it? It doesn't sound like OP is in dire straits...
 
Messages
10,592
Location
Cincinnati, OH, USA
Originally Posted By: AZjeff
Originally Posted By: krismoriah72
If you have free time on your hands you can start looking at junkyards and probably find a shiny one that someone has replaced and put it in the trunk.
Steal it? It doesn't sound like OP is in dire straits...
I think he means a recently replaced one, or a spare in the trunk of the junked car, & buy that one (?) I've bought a few radiators like that-PO bought & installed thinking it would fix their overheating problem-but a cracked head/block or blown HG later gave up & junked it (or parted it out on CL, my personal favorite).
 
Messages
1,087
Location
Minneapolis
They're generally pretty easy to rebuild. I woulnd't worry too much about where the brushes ride. You can just smooth it out with some emery cloth while spinning it by hand. It's satisfying to do this yourself and produces a better result than anything from Autozone.
 

Kestas

Staff member
Thread starter
Messages
13,863
Location
The Motor City
Originally Posted By: AZjeff
Originally Posted By: krismoriah72
If you have free time on your hands you can start looking at junkyards and probably find a shiny one that someone has replaced and put it in the trunk.
Steal it? It doesn't sound like OP is in dire straits...
I think he meant place it in the trunk to keep as a spare. The engine I have is a Vulcan.
 
Top