Easy Alternator fix / refurbish
The symptom of worn-out brushes is the light comes on at engine speed.. typically highway cruise and recovers to charge at lower rpm. Verify by tap on rear alternator housing, usually resumes charging.
For me, usually happens between 150- 200 K miles.
This is a good alternative to buying a rebuilt as well. Get from a salvage yard - about $35 -and inspect it on the spot for tight yet free spinning, with little to no 'singing' noise.
- note: the best yards will sell you the best merchandise they have. And I'm betting most of the worst is sent directly to rebuilders.
If the alternator has not overheated or been zapped, there is every reason to expect the regulator and diodes to last until the bearings go.
In fact, you dont know that the "rebuilt" hadnt been done exactly like
this, just cleaned up more.
As of July 2011 brush assy were still available from NAPA. Rockauto has many options from individual brushes to complete assy much cheaper.
If your mid-90's Ford has run up it's mileage to about 100 - 150 kmiles
or so, you might want to undertake a quick Saturday project that will
probably save you big bucks -and inconvenience- in the near future.
Check out the back of the alternator to see if the voltage regulator (at
the connector with the smaller wires) is held on by small torx screws. If so this is the version I'm describing. (Many older alternators are built similar to this)
If so, refurbishing which COULD be better than "rebuilding" - for a guy
who is at all handy should be piece of cake.
- 3/8 or 1/2 inch breaker bar or whatever you use to release belt
- appropriate metric or sae tools for automotive access service.
- 1/4 inch driver and small sockets plus small standard torx bits
- standard size paperclip
- brush replacement set for your year, model and engine As of July 2011 brush sets were still available from NAPA.
- new belt, optional
- a dab of high temp bearing grease
Release tension and remove the belt, then listen carefully while you spin
the pulley and check for free-spin and listen for bearing singing -you
want to hear a little but no grinding or roiugh sounds- then wiggle the
pulley back and forth, no sloppiness wanted.
If it fails these, put the belt back on.
Pull the connectors - they may be a little stiff- and unbolt the
With tape or marker, run a reassembly line from back housing to front
Remove the three housing bolts, tap the edges of the front (pulley-side)
to loosen from stator (center section) and pull out by the pulley.
- Now you can check the front bearing for wear. Spin the front housing while holding rotor. Should spin freely with little to no bearing sing. Wiggle front housing.. outer edge no more than 1/8 or so travel.
If the bearing seems worn, you CAN pull the pulley and try to find a replacement bearing at bearing supply house. If you have the time and tools and patience. I prefer to just hit the junk yard and use those brushes on a better candidate.
The stator and back housing are connected, dont attempt to separate.
Check commutator (brass rings) for galling and copper incursion into
separator between them... if brush had gone and either is grooved
continue on, the new brushes will just not last as long. Use fine
sandpaper to smooth it if ring surface is rough.. DO NOT attempt to sand
more than to get the high points off.
Check back bearing for some grease and for no "wash-board" on rotor shaft
This is a break-point: if the bearing/surface or commutator (and SOME
brushes left) is in poor shape, you may want to just reassemble and plan
to replace alt.
Remove the torx screws AT THE CORNERS of the regulator and remove it from
Remove the two torx screws that fasten the brush terminals to the
regulator body. make sure not to lose the nuts.
blow or brush dust from brush holders/reg and insert the new springs and
brushes, note that the wire slot aligns brush terminal with proper
do rear brush first, sliding straightened clip in to hold it in, then
front brush, sliding clip further in to hold both brushes in
fasten terminals with nuts and torx screws tighten just secure, not
Using just enough grease to "skin" the bearing rollers, lube the shaft
If you're going to blow dust out of the
rear housing, plug the bearing cavity tightly with paper towel.
Remove towel from bearing, put in dab of grease, 'dab meaning enough to fill spaces between rollers but not enough to obviously squish out.
Reinstall regulator, then carefully slide alt back together following the marked alignment.
Make sure stator and each housing mate squarely.
Install the three housing bolts and tighten alternately until very
secure. not ultra tight.
Check for free-spin. Pull out paperclip/brush retainer pin
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Originally posted on Alt.autos.ford newsgroup
I learn more about cars every day!
I do it just because I still want to know HOW and WHY!!! Quit learning=die. Be informed as to WHAT, rather than learn,=brain-dead already.
1993 Silver LX 3.8L My Bravadiva's 'go store-fetch me parts' girl
Last edited by pettyfog; 07-17-2011 at 09:34 PM.