Would like to rebuild an 10DN alternator,. There are kits our there but have not found much on how to rebuilding them (beyond the service manual). Looking for feedback from someone who has rebuilt an 10DN - thanks

 

I would trust the service manual over anything I read on the web. Just sayin'.
This is not difficult. The biggest challenge is getting the nut that holds the pulley loose. Also, pay attention to where the spacers under the pulley go. Use a wooden toothpick to hold the brushes in place as you put the alternator back together. And be careful installing the front bearing, as its a tight fit and can wedge in the case.

 

I've done a couple of 12SI rebuilds using all Delco parts and they're not complicated. VERY close to doing a 10SI, but not exactly like a 10DN. Just ensure any spacers are properly identified as to which thickness goes where during reassembly. When redoing a 10 series, I'd hesistate to buy those monster amp conversion kits. I personally believe they overload the cooling arrangement on those 10s. But, it's your money. IIRC, the 10DN has round diodes that normally come in the kit and those are press fit in the inside backing plate.

Shaft nut: Borrow, beg or steal if you don't have an impact wrench. If memory serves, it's a 15/16" nut. Wear leather gloves, grab the fan and hold it tight, then zip off the nut. Just a couple of ugga-duggas and it's off. You will fight it, and could damage stuff if you don't use an impact. I reinstall with about 2 ugga-duggas and never had an issue. I think the spec is around 60 lbs/ft, but as long as it's not coming off, I call it good. But if you're bold, good luck holding that shaft still while you use a crow's foot to torque it.

Rear bearing: I've talked to like a zillion people, including lubrication engineers, about re-greasing these bearings. Nobody seems to know exactly which grease to use. Most lean to "likely using" EM, or electric motor bearing grease, and that makes sense. Some people just don't care and use any old grease. Just don't use moly-based, as they're roller needles in there and moly could allow them to slide, and don't overgrease them. Luckily, replacements are relatively chaep and come pre-greased. Get the newer style if yours has a separate seal. I always get the Delco/GM parts, so everything is ready to go. Use a properly sized socket or round steel dowel just smaller than the bearing cap diameter and press to push the old bearing toward the FRONT, or inside of the casing half. Push it into the case until it falls out. Ensure the hole is clean and smooth. No need for sealer or anything. Press fit. Place new bearing and press it in straight until the back of the bearing cap is FLUSH with the boss. You're done with that install.

Front bearing removal- press it out from the front. Ensure to support the casing half on the inside around the bearing boss to ensure you don't deflect or break the casing. I can't think of any easy way to do it otherwise.

Front bearing installation- easy peasy. If yours has the single sealed front roller bearing, you can use double sealed bearing in its place and avoid all that extra crap of the separate seal, etc. Night before you install: put bearing in a plastic sandwich bag or wrap with saran wrap if not already in a factory bag (cleanliness concern). Put bearing in the freezer overnight. When ready to do the job, heat the front half of the prepped casing (cleaned, blasted, painted, whatever you need to do to it) in an oven. Heat at around 275-300 or so degrees F for 15 minutes or so. Remove casing half, wearing heat gloves or something to handle it with. Quickly remove bearing from freezer, and drop it in the bearing hole. Should plop right in, and you should hear it hit bottom. Using a non-marring tool like a screwdriver handle, quickly press it in if it doesn't seat immediately. Set it on the bench and let the temps return to ambient.

If your condenser is still in place, and you don't want to replace it or if you don't have a new condenser, it's only for alternator radio noise, so you could add an external one if yours don't work and you don't want to or can't replace it in the alternator.

If you're scared of doing it yourself, you can always get a replacement for fairly cheap. Unless you want to maintain the correct date codes and such. New Delco numbers 1100849 or 1100883.

MCR - Delco Replacement 1100849, 1100883 Alternator

 

Thanks for the information/tips!

 

I did mine in March. I agree, use the service manual to see where the parts go. Biggest problems I had was:
- make sure the rear bearing is pressed in far enough. The outside should be even or a little more out of the case. I had to take my alternator apart a second time as it was to tight and not spinning freely.
- Make sure to get the positives and negatives correct. See manual. I cut a slot into a 1/2 inch thick nut so I could fit it over the wire to press them in.
- The spacer for the capacitor screw broke on me. A replacement was not in the kit I bought, so I had to make one.
- Do all the electrical checks suggested in the service manual. You don't want to put it together and find out the core is bad.
Good luck.

 

I've heard of this rear bearing thing happening, although infrequently. I've only used GM rear bearings and never had an issue installing them per the CSM instructions. I wonder if it has something to do with using a different brand bearing with a questionable source, like those that come in some of the kits? Another possibility is case half deflection by not supporting the bearing boss while pressing the rear bearing in or when pressing the front bearing out. This could allow the rotor to bearing position to end up slightly more to the rear, causing a clearance issue.

 

At 1 time I use to know all of the replacement kits and parts numbers in my head. Well 30 years later I have forgotten this information. Does anybody have the kit information or part numbers that they can list here?

 

I got mine off of Ebay https://www.ebay.com/itm/201927134673

 

Pulling it apart was easy, just checked it all out to see the condition and put it back together for now. I have tried the reman. route before. The last one/current one I have is still fine after about 7 years, just to me the bearing was a little louder, was concerned it would degrade soon so tried to pick up a new reman unit. However after trying two new reman units last summer, and one again this year which all sounded bad, .mine is not that bad at all/fine for now until I rebuild it, or find a good replacement..