How to: 4g alternator rebuild with pictures

[koda2000]

Great write-up @donalds. I've saved the link to the parts source.

I replaced 2 alternators 6 years ago with Autozone rebuilt's (with lifetime warranties). They're both still working fine, but if I have problems in the future I may just rebuild them myself. I may just me lucky, but I've never had any problems with rebuilt Autozone stuff (like starters, alternators, brake calibers). I'd never buy a rebuilt water pump or cam sync though. Not worth the risk and I'd never buy their "Valuecrap" stuff.

 

[donalds]

@koda2000 I think the bad rebuilt alternator s
That different people all over the US
Have experienced is some local builders in different places just suck

Must be a good builder around you hehe
Mine has the lifetime duralast warranty to no one will ever know I took it apart

 

[koda2000]

@koda2000 I think the bad rebuilt alternator s
That different people all over the US
Have experienced is some local builders in different places just suck

Must be a good builder around you hehe
Mine has the lifetime duralast warranty to no one will ever know I took it apart

I once looked into having an Expl alternator rebuilt by a local re-builder I've used (with success) many times before. He said that the typical problem he finds with these alternators is that the armature shaft gets worn down, presumably when the bearings fail, and that rebuilding is then about the same cost as replacement. IDK.

 

[donalds]

Yea the slip ring wears my original one lasted a long time
The kit was not to bad $65 Inc shipping
The one I rebuilt had bad bearings
A bad voltage regulator brush assembly
That someone rebuilt tried to install new brushes with week springs why Idk
But the slip ring was like new prob the week springs on the brushes

Just looked at rock auto out of curiosity bc you mentioned it's about the same price to rebuild for a new good one like a.c. Delco or Bosch _$150 here is a pic of a worn out slip ring

 

[4pointslow]

Nice write up!
Good job on the rebuild too!
Probably never have to mess with it again.

 

[BrooklynBay]

Terrific how to thread! I have a how to thread on the older model alternators. I saw that you're getting 14.75 volts. This is probably while it's cold. The voltage output reduces as it warms up on the internal regulators. I saw that your regulator has a built in aluminum heat sink. Maybe the output will be slightly higher since it dissipates the heat better. Check the output with a voltmeter when it's warm to compare readings. What is the amp rating of your alternator? Did you increase the rating with the rebuild kit? Did you use thermal transfer grease on the back of the regulator?

 

[donalds]

130 amp factory no upgrade
It's recommended to use dielectric grease on the contact points of the regulator so I used that thermal heat transfer paste I did not even think of using it and I even have a tube of it to

The rebuild guy said to use dielectric grease or white lithium grease
Thermal paste will work the same

I did check it as it warmed up and it was 14.4 while hot hopefully that's on point

 

[CDW6212R]

Great DIY pictorial, well done.

I've had one rebuilt that was an aftermarket, my local shop wasn't impressed with the guts in it at all. I bet you are right about quality of builders and the kit parts. It's hard to know what to get and where.

 

[RickOTR]

Here's some great info on the 4G SOHC Alternator:

http://p71interceptor.net/alternator/convert4g6g/pcmalternatorpdfs/regulatorjpg/techup32_web.pdf

 

[jawknee99]

Nice! Great job

 

[donalds]

Here's some great info on the 4G SOHC Alternator:

http://p71interceptor.net/alternator/convert4g6g/pcmalternatorpdfs/regulatorjpg/techup32_web.pdf

Hay thanks for info

 

[Gary Crist]

Thanks @donalds great write-up! I have always wondered about "high out-put"
4Gs and after reading I wonder if it is the V setting of the regulator?
I came across this site

National Quick Start Sales, High output alternator, Alternator & Starter Parts

It got me wondering.

 

[donalds]

Thanks @donalds great write-up! I have always wondered about "high out-put"
4Gs and after reading I wonder if it is the V setting of the regulator?
I came across this site

National Quick Start Sales, High output alternator, Alternator & Starter Parts

It got me wondering.

Interesting

 

[RickOTR]

Here's what I used to rebuild my Alternator

Ford 4G Alternator Slip Ring FORD LINCOLN MAZDA MERCURY | eBay

Find many great new & used options and get the best deals for Ford 4G Alternator Slip Ring FORD LINCOLN MAZDA MERCURY at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Alternator Brush Pair Fits Ford Motorcraft 4G Alternator F76 | eBay

Find many great new & used options and get the best deals for Alternator Brush Pair Fits Ford Motorcraft 4G Alternator F76 at the best online prices at eBay! Free shipping for many products!

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Pardon Our Interruption...

Have 215,000 miles on this alternator rebuild

 

[DP96XLT]

Since this thread is about rebuilding a stock "OEM" alternator, I figured I would ask here...

I have a stock, low-mileage (42k miles) alternator I went through, put new slip-rings, new brushes and holder, new bearings (all NTN premium bearings) and after the rebuild it had the same issue as it had before I tore it apart, which was a knocking at lower RPM.

Upon inspection I couldn't find any evidence of the rotor hitting the stator, there was no play in the new bearings, the case was firmly bolted together, there was no extra play in the rotor shafts to bearings or anything else obvious. (I will note that the original bearings were loose and rattling, thus why I figured they were the original source of the knocking I noticed before ordering new parts, but ultimately after the rebuild, I am having the exact same issue as before the rebuild.)

In the meanwhile I built up a new super-duty 240amp unit from all new parts that I added a smaller overdrive pulley to along with a shorter belt and have no issues. I would also like to figure out what is wrong with the OEM alternator to have as a spare.

 

[CDW6212R]

Since this thread is about rebuilding a stock "OEM" alternator, I figured I would ask here...

I have a stock, low-mileage (42k miles) alternator I went through, put new slip-rings, new brushes and holder, new bearings (all NTN premium bearings) and after the rebuild it had the same issue as it had before I tore it apart, which was a knocking at lower RPM.

Upon inspection I couldn't find any evidence of the rotor hitting the stator, there was no play in the new bearings, the case was firmly bolted together, there was no extra play in the rotor shafts to bearings or anything else obvious. (I will note that the original bearings were loose and rattling, thus why I figured they were the original source of the knocking I noticed before ordering new parts, but ultimately after the rebuild, I am having the exact same issue as before the rebuild.)

In the meanwhile I built up a new super-duty 240amp unit from all new parts that I added a smaller overdrive pulley to along with a shorter belt and have no issues. I would also like to figure out what is wrong with the OEM alternator to have as a spare.

I would take that to a local alternator shop and allow them to fix it. The cost should be about the same as if you knew the issue/part to replace, plus minor labor costs. That would also save you the time and worry of figuring it out, I would consider the shop labor to be cheaper than your own time.

 

[donalds]

I would take that to a local alternator shop and allow them to fix it. The cost should be about the same as if you knew the issue/part to replace, plus minor labor costs. That would also save you the time and worry of figuring it out, I would consider the shop labor to be cheaper than your own time.

I agree take it in its out of balance

 

[D Hook]

Thanks for the write up. Not certain yet my alternator is going out or not but will keep this for reference.

 

[RickOTR]

FYI, those slip rings are polarity sensitive so if you install them backwords, the alternator will discharge the battery and lead to major problems.

 

[JustAnotherMember7]

Thanks for the thread!