keywords: Ford Expedition alternator replace change install how to

The battery light came on in my wife's 1999 Expedition (94,000 miles) and it was apparent that the battery that I had installed a couple of months ago was being drained. After I found out that my favorite shop was booked solid for more than a week, I decided to take matters into my own hands. I started by charging the battery and driving down to the local AutoZone store for an in-vehicle check of the alternator which they told me was the problem. So I bought a remanuafactured alternator ($150), a new belt ($30), and a packet of dielectric grease (99 cents) and I was on my way. Because I wasn't able to find any instructions on how to change the alternator, I thought I'd post them here. This took about an hour and a half start to finish and I didn't have any major glitches.

Start by removing one of the terminals from the battery to make sure the alternator is electrically disconnected.

Remove the plastic throttle body cover (three 12 mm bolts I think it was) and remove the plastic air intake at the throttle body (one hose clamp). I used some string to tie back the intake tube so it was out of the way.

Note how the fan/accesssory belt is routed over the many pulleys and idlers so you remember how to put it back on.

Remove the belt. The belt has a spring-loaded tensioner (somewhat between the alternator and the air conditioner compressor). If tension is removed from the belt it can be slipped off the alternator pulley. I was told by Mr. AutoZone that you could use a 1/2 inch socket wrench handle (the square end fits into the end of the tensioner) as a lever to remove tension but I ended up taking a different approach. Perhaps if I had some help I could have done this from underneath the front end but I was flying solo.

Removing the tension can be done without tools although a 2 foot long piece of 1x1 wood makes a good push bar for the belt tensioner. I was able to get the belt off with a combination of pulling on it and pushing the end of the tensioner with the piece of wood, slipping the belt off the alternator pulley. One nice piece of engineering is that the belt comes completely off without having to remove any other parts. You don't even have to work it around the fan blades to get it off, very nice.

The electrical connections include a thick cable with a terminal (this connects the alternator to the battery), plus two plugs. Slide the black boot up the thick cable to reveal the 10 mm nut that connects the wire to the alternator and remove the nut and cable from the alternator.

The alternator is mounted with 2 bolts (10 mm) on the bottom and a small bracket on a the top. Remove the two bolts on the bottom. Caution: I used a 3/8 socket wrench with a 3 inch extension and by the time one of the bolts was nearly out, the back of the wrench was up against the fan hub. I could tell I wasn't going to remove the bolt this was so I put it back in enough to remove the wrench, took off the extension and then was able to remove the bolt.

I chose to remove the entire bracket (two 10 mm bolts on the engine, one on the alternator) but you could probably do the job by just removing the one bolt holding the alternator and leave the bracket attached to the engine. I also chose to unbolt the alternator first so I could tilt it to get a better view of the plugs and their retaining clips. Once the alternator is free you need to remove the two remaining electrical connections. I used a very small (narrow) flat head screwdriver to lightly pry up the plastic retaining clips and the plugs popped right out. They will not come out without doing this so don't pull too hard.

It's a tight fit but the alternator can now be removed by working it out straight up between the engine and the radiator hose.

Transfer the mounting bracket to the new alternator but leave the mounting bolt a bit loose in order to allow for proper aligmnet later.

Prep the electrical connections by smearing the termininals on the alternator with a light coating of dielectric grease. The grease ensures a good electrical connection over time by minimizing corrosion. Don't glob it on, a little coating is all you need. Thereoretically, if you put too much on it could provide an electical path to ground, since the grease is designed conduct electricity. You may also want to use some sandpaper to remove any corrosion on the terminal on the large cable and put some grease on it too.

Install the new alternator by attaching the short bolts on the bracket at the top to the engine and the two long bolts at the bottom. Tighten the two bottom bolts first then the three remaining bolts on the bracket at the top. Plug in the two connectors. I looked at the old alternator to determine the orientation of the retaining clip since these are hard to see on the new alternator after the alternator is installed. Make sure the clips snap back into place. The wires should not come off with a light pull on the wires. Attach the large cable and slip the boot back into place.

Replace the fan/accesory belt by pushing it between the idler pulleys on and near the tensioner. Slip the belt over the air conditioner compressor and feed it back over the other pulleys, saving the alternator pulley for last. Make sure the belt is correctly positioned in all the pulleys, if it doesn't look right it probably isn't. I used the stick on the tensioner and brute force again to slip the belt over the alternator pulley. Two sets of strong arms would be nice for this step but I was able to do it myself. Make one last check to ensure the belt is on each pulley correctly. Replace the intake and the throttle body cover.

Start the engine and the check battery light should now be off.

Congratulations!

 

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Tigger22 had posted a very helpful set of notes on replacing his alternator, back in December 2004. Since I just did my own alternator replacement, with the help of his notes, I thought I'd add a couple of my own comments (see below).

For reference, in my case the problem was that the Battery light started coming on at high RPMs. There are a lot of posts on this symptom - most of which end with "problem solved by replacing the alternator". In my case, I also noticed that the voltage put out by the alternator would droop from 14 volts or so to less than 13 (more like the raw battery voltage) when I revved the engine (using a multimeter - you couldn't see any change in the dash voltage gauge).

My 2000 Expedition has 102,000 miles and so although I figured it was the alternator, I also felt it was time for a new belt and battery. I bought all three at Kragen Auto Parts - a reman. Autolite alternator for $155 (new was $185), an Autolite 96 mon. battery ($79), and a Dayco belt ($50). All of these might have been a tad cheaper if bought on-line, but I wanted to get them that day. Actually, I discovered something interesting about Kragen - you can order the ports online, find out whether they are in stock at local stores, and then pick them up an hour or so later at the store. Further. the on-line Kragen prices were a little less than the store quoted me over the phone.

I went with a reman. alternator, because the list of things that were new on it basically included everything of any consequence. The belt is one of those that has the "segmented" ribs. Supposedly these are quieter, but I guess I care more about whether they last as long as one with regular ribs. It's the only kind they carried, in any case. (The old belt was the original Motorcraft, which showed surprisingly little sign of wear, considering the 102,000 miles.)

I've inserted a few comments on what I did a little differently from Tigger22's original procedure:


how to install an alternator
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Start by removing one of the terminals from the battery to make sure the alternator is electrically disconnected.

Remove the plastic throttle body cover (three 12 mm bolts I think it was) and remove the plastic air intake at the throttle body (one hose clamp). I used some string to tie back the intake tube so it was out of the way. (added comment - even though there are still two hoses attached to the intake tube, it still bends enough to get it sufficiently out of the way)

Note how the fan/accesssory belt is routed over the many pulleys and idlers so you remember how to put it back on.

Remove the belt. The belt has a spring-loaded tensioner (somewhat between the alternator and the air conditioner compressor). If tension is removed from the belt it can be slipped off the alternator pulley. I was told by Mr. AutoZone that you could use a 1/2 inch socket wrench handle (the square end fits into the end of the tensioner) as a lever to remove tension but I ended up taking a different approach. Perhaps if I had some help I could have done this from underneath the front end but I was flying solo.
(Added comment: It is FAR easier to use a socket wrench or a long-handled wrench like a torque wrench. But you need a 1/2" square drive (male), which is different than the 3/8" drive of many socket sets, or a 3/8 to 1/2" drive adaptor.)

Removing the tension can be done without tools although a 2 foot long piece of 1x1 wood makes a good push bar for the belt tensioner. I was able to get the belt off with a combination of pulling on it and pushing the end of the tensioner with the piece of wood, slipping the belt off the alternator pulley. One nice piece of engineering is that the belt comes completely off without having to remove any other parts. You don't even have to work it around the fan blades to get it off, very nice.

The electrical connections include a thick cable with a terminal (this connects the alternator to the battery), plus two plugs. Slide the black boot up the thick cable to reveal the 10 mm nut that connects the wire to the alternator and remove the nut and cable from the alternator.

The alternator is mounted with 2 bolts (10 mm) on the bottom and a small bracket on a the top. Remove the two bolts on the bottom. Caution: I used a 3/8 socket wrench with a 3 inch extension and by the time one of the bolts was nearly out, the back of the wrench was up against the fan hub. I could tell I wasn't going to remove the bolt this was so I put it back in enough to remove the wrench, took off the extension and then was able to remove the bolt.

I chose to remove the entire bracket (two 10 mm bolts on the engine, one on the alternator) but you could probably do the job by just removing the one bolt holding the alternator and leave the bracket attached to the engine. I also chose to unbolt the alternator first so I could tilt it to get a better view of the plugs and their retaining clips. Once the alternator is free you need to remove the two remaining electrical connections. I used a very small (narrow) flat head screwdriver to lightly pry up the plastic retaining clips and the plugs popped right out. They will not come out without doing this so don't pull too hard.

(Added comment: I undid the bolts a little differently. I loosened the two bottom bolts, so that they were fully out of the threads, but left them in place so that the alternator was resting on them. Then I removed all three bolts on the upper bracket, and pulled the bracket piece out, to get it out of the way entirely. Then I could easily pull out the loose lower bolts as the last step. I agree that you want to rotate the alternator a bit to get a better view of the two connectorized electrical connections, so you can see where you need to pry out the plastic retaining tabs. The retaining tabs are only on one side of each of the two connectors. I'd remove the smaller connector first, as the wires to it are fairly fragile-looking.)

It's a tight fit but the alternator can now be removed by working it out straight up between the engine and the radiator hose. (Added comment: It helps to temporarily push the radiator hose to the other side of it's support bracket.)

Transfer the mounting bracket to the new alternator but leave the mounting bolt a bit loose in order to allow for proper aligmnet later.

Prep the electrical connections by smearing the termininals on the alternator with a light coating of dielectric grease. The grease ensures a good electrical connection over time by minimizing corrosion. Don't glob it on, a little coating is all you need. Thereoretically, if you put too much on it could provide an electical path to ground, since the grease is designed conduct electricity. You may also want to use some sandpaper to remove any corrosion on the terminal on the large cable and put some grease on it too.

Install the new alternator by attaching the short bolts on the bracket at the top to the engine and the two long bolts at the bottom. Tighten the two bottom bolts first then the three remaining bolts on the bracket at the top. Plug in the two connectors. I looked at the old alternator to determine the orientation of the retaining clip since these are hard to see on the new alternator after the alternator is installed. Make sure the clips snap back into place. The wires should not come off with a light pull on the wires. Attach the large cable and slip the boot back into place. (Added comment: Again, I did it in a different order - first inserted the two bottom bolts, and got the threads started a bit. Then I got the electrical connectors back on. My thought was that if I needed to tilt the alternator to do this, it would be easy to slip the lower-right bolt back out and pivot the alternator on the lower-left bolt. But, it turned out to be easy enough to get the large connector on by feel, and then the small connector. Then, I snugged up the bottom bolts, and then put the upper bracket back on using all three of its bolts. Then, tightened everything.)

Replace the fan/accesory belt by pushing it between the idler pulleys on and near the tensioner. (Added comment: slip the flattened loop of the belt between the two idler pulleys, and have it go under the AC compresser before "opening the loop".) Slip the belt over the air conditioner compressor and feed it back over the other pulleys, saving the alternator pulley for last. (Added comment: Once you have the loop over the AC compressor pulley, you want to drape the belt over the smooth (non-ribbed) water-pump pulley, and then shove a loop past the right side of the water-pump pulley, but above the lower crankshaft pulley. Once you have expanded the belt over the crankshaft pulley, you can push the slack over the power-steering ribbed pulley on the right. Only pulley not covered at this point is the alternator.) Make sure the belt is correctly positioned in all the pulleys, if it doesn't look right it probably isn't. I used the stick on the tensioner and brute force again to slip the belt over the alternator pulley. Two sets of strong arms would be nice for this step but I was able to do it myself. Make one last check to ensure the belt is on each pulley correctly. Replace the intake and the throttle body cover. (Again, with a 1/2" drive socket wrench or long-handled torque wrench, it is a piece of cake.)

Start the engine and the check battery light should now be off. (Added comment: Since you have disconnected the battery, expect the gauges to "sweep" when you first turn the ignition on. Also, the ECM has to "relearn" its idle conditions - the manual says to let it idle in Park for 1 minute, then idle in Drive for one minute. It may still take some driving for the relearning process. My radio retained its presets, and also kept the trip computer's "compass zone", but I lost my power seat memory settings.)

Congratulations! (You have saved yourself some money!)

 

This thread is 3 years old now but I'd like to bring it back from the grave, considering we're getting near Halloween, and all.
My wife and i just took a trip to Florida from Georgia. On the 500+ mile trip back home, the battery light came on but the volt meter was still fine. the light would go off every now and then and come back on. As we neared home, I noticed the voltage starting to go down. Within a couple of miles from home we lost all electricity. The gauges all bottomed out. I had a car behind me but I couldn't signal and couldn't lower the (electric) window to use a hand signal, so I slowed down, pulled to the side while they passed and went into our driveway. I put the Expedition in reverse and it died. I couldn't start it back up again. Talk about luck! After 500 miles the car dies in our driveway.

Anyhoo, I just finished replacing the alternator and life is good. I had a heck of a time getting the belt back on. The sharp edges of the plastic around the fan were just cutting my forearms to pieces and I was trying to push my 1/2" socket wrench down while getting my arm sliced and trying to pull the belt up onto the alternator. But my arm that was pushing the wrench down was in the way.
So, here's how I ended up doing it.
I got a ratcheting tiedown from my truck, hooked it onto the wrench handle and underneath the Expedition, attached it to something sturdy. I ratched 'til it pulled the wrench down enough so i could slip the belt onto the alternator.
The tension on the tiedown was so strong I couldn't release the ratchet so I just cut it - it was a cheap tiedown anyway.
So, mission accomplished, thanks to this thread.

 

Sounds like a cool method for ratcheting down the tensioner. I just slip an old 2ft piece of 1/2" pipe (that I 'borrow' from one of my wood project pipe clamps) over the end of the ratchet with the ratchet end pointing upward toward the top of the engine. Gives you plenty of torque and room to pull the tensioner down completely, without having your arms touch the fan, and allows you to use your free hand to roll the belt over the final pulley at the same time. Then I put the pipe clamp ends back on the pipe and hang it back up on the wall. Sometimes, solutions can be staring right back at you from the wall in your garage! Hope this helps.