FINOCJ
December 1st, 2020, 01:29 PM
At one time for about 30 years, the Delco 10si was the most common alternator around - and its slightly improved, larger output cousin the 12si....I run these on both my 70cj5 and the 58 willys with sbc....the one on the cj was working fine in terms of electrical output, but started making a growling noise on the way back from Holy Cross a couple months ago - basically a bearing was going bad, and it only got worse on the next couple runs....These rebuilt NAPA/Carquest etc units are pretty cheap, but I had done some work to the housing sleeve to help stabilize the mount, and figured it was worth an attempt to replace.....Most likely it was the wobbly mount that lead to the bearing wear....
This summer I put in a sleeve on the bottom bolt/pivot - I think when they 'refresh' these housings, they are over enlarging the mount hole as the one on the sbc is the same - I tried just swapping it out at first. In this case, I drilled out the hole just a bit, and put in a sleeve that fits the mounting bolt perfectly, and used a touch of epoxy to hold things in place. That solved the wobble problem, but I think the bearing damage was already done and it didn't take but a couple months for it to start growling.
https://beamingpix.com/images/2020/11/30/PXL_20201130_211820259.jpg
When you separate the two halves, the back half has the stator ring (wire coils - not pictured here, but is below) as well as the rectifier (rectangular finned thingy that changes alternating current to DC) as well as the dual plastic housing for the spring loaded brushes and the internal voltage regulator (this is a 3-wire unit), the diode trio, as well as a needle bearing cap that sits in the back of the housing....this is one of the two bearings to be replaced. You can also see the brushes are pushed out by the springs when the rotor is removed....
https://www.beamingpix.com/images/2020/12/01/PXL_20201201_011629071.jpg
Here are the brushes up close (and the voltage regulator underneath and the diode trio on top):
https://www.beamingpix.com/images/2020/12/01/PXL_20201201_012439538-1.jpg
One of the brushes in particular was worn significantly more than the other - usually that means a bad spring, but in this case its just kind of weird....but you can remove the brush with its metal clip and replace:
https://www.beamingpix.com/images/2020/12/01/PXL_20201201_175715217.jpg
The other front half holds the pulley, fan, front drive bearing and shaft along with the rotor that spins inside the stator coils - sorry no pic....but here is the back half with new needle bearing installed, the new front drive bearing, and the brush housing....a paperclip or pin can be used to hold the brushes back against the springs until everything is installed.
https://beamingpix.com/images/2020/12/01/PXL_20201201_164044349.jpg
Reassembly of the back half with new needle bearing in the bottom, new brushes, and stator ring in place:
https://www.beamingpix.com/images/2020/12/01/PXL_20201201_172959926c2dde112087a1482.jpg
I put the front half in the oven for 10 min with the bearing in the freezer so it slipped right in - no need to have to pound it in....
https://www.beamingpix.com/images/2020/12/01/PXL_20201201_173234927.jpg
Assemble the two halves of the case back together...and you can see the pin that holds the brushes in has a hole through the back of the case that can be removed (pulled out) as the last step allowing the brushes to push against the rotor....
https://www.beamingpix.com/images/2020/12/01/PXL_20201201_175744600.jpg
Sorry I didn't get pics of the front halve with the drive bearing and rotor - I wasn't really thinking about a full write-up - but its pretty straight forward. The front case half has a bearing in the front opening that the rotor shaft goes through, the fan and pully slide on the outside end of the shaft, and then you tighten it down with nut...
This summer I put in a sleeve on the bottom bolt/pivot - I think when they 'refresh' these housings, they are over enlarging the mount hole as the one on the sbc is the same - I tried just swapping it out at first. In this case, I drilled out the hole just a bit, and put in a sleeve that fits the mounting bolt perfectly, and used a touch of epoxy to hold things in place. That solved the wobble problem, but I think the bearing damage was already done and it didn't take but a couple months for it to start growling.
https://beamingpix.com/images/2020/11/30/PXL_20201130_211820259.jpg
When you separate the two halves, the back half has the stator ring (wire coils - not pictured here, but is below) as well as the rectifier (rectangular finned thingy that changes alternating current to DC) as well as the dual plastic housing for the spring loaded brushes and the internal voltage regulator (this is a 3-wire unit), the diode trio, as well as a needle bearing cap that sits in the back of the housing....this is one of the two bearings to be replaced. You can also see the brushes are pushed out by the springs when the rotor is removed....
https://www.beamingpix.com/images/2020/12/01/PXL_20201201_011629071.jpg
Here are the brushes up close (and the voltage regulator underneath and the diode trio on top):
https://www.beamingpix.com/images/2020/12/01/PXL_20201201_012439538-1.jpg
One of the brushes in particular was worn significantly more than the other - usually that means a bad spring, but in this case its just kind of weird....but you can remove the brush with its metal clip and replace:
https://www.beamingpix.com/images/2020/12/01/PXL_20201201_175715217.jpg
The other front half holds the pulley, fan, front drive bearing and shaft along with the rotor that spins inside the stator coils - sorry no pic....but here is the back half with new needle bearing installed, the new front drive bearing, and the brush housing....a paperclip or pin can be used to hold the brushes back against the springs until everything is installed.
https://beamingpix.com/images/2020/12/01/PXL_20201201_164044349.jpg
Reassembly of the back half with new needle bearing in the bottom, new brushes, and stator ring in place:
https://www.beamingpix.com/images/2020/12/01/PXL_20201201_172959926c2dde112087a1482.jpg
I put the front half in the oven for 10 min with the bearing in the freezer so it slipped right in - no need to have to pound it in....
https://www.beamingpix.com/images/2020/12/01/PXL_20201201_173234927.jpg
Assemble the two halves of the case back together...and you can see the pin that holds the brushes in has a hole through the back of the case that can be removed (pulled out) as the last step allowing the brushes to push against the rotor....
https://www.beamingpix.com/images/2020/12/01/PXL_20201201_175744600.jpg
Sorry I didn't get pics of the front halve with the drive bearing and rotor - I wasn't really thinking about a full write-up - but its pretty straight forward. The front case half has a bearing in the front opening that the rotor shaft goes through, the fan and pully slide on the outside end of the shaft, and then you tighten it down with nut...