One of the most critical components in our trucks is the alternator. This little generator creates all the electricity needed to keep our cylinders firing, radios running, and gizmos charged up. Working as hard as it does, it's downright amazing how robust the stock alternators are, even if they only generated 60A-80A when they were new from the factory!
In fact, the most common failure I've seen is that the brushes - a wear component - get worn down and stop making contact with the spindle. When this happens, the alternator stops working and the battery light on the dash turns on. Luckily, this is an easy - and inexpensive - part to replace.
In other cases, especially when there are additional loads on the alternator - aftermarket lighting, winching, charging/running of a house electrical system - it can be a good idea to upgrade the stock alternator to one that outputs more current. This too is relatively easy, and there are several options that bolt right in.
Parts
Regardless of whether you need new brushes in your alternator or whether you're installing an entirely new generator, the general approach is the same - remove the alternator to work on it or replace it - and then bolt it back in for continued service. So, let's get down to it.
Replacing Brushes
- Toyota OEM Alternator Brushes (27370-75060) - the only part you'll need for the job.
Replacement Alternators
If you want to replace the alternator with a stock replacement, pick up a Denso 210-0434 80A Alternator. This will bolt right in because you'll be pushing stock current, there's no need to upgrade any of the stock wiring.
There are several options for higher powered alternators, each ranging in price, power, and ease of installation. Note that whenever a higher-powered alternator is installed, the wiring and fusing for the alternator also needs to be upgraded (see High Output Alternator Wiring Upgrade, below).
- Denso 210-0461 105A Alternator - At 105A, this alternator isn't as powerful as some of the DC Power high-output alternatives, but it still provides 30-90% more juice than the stock alternator and uses the same housing and connectors so it bolts right in, making it a super simple swap. Plus, because it's a standard alternator for a Suzuki, it's very reasonably priced.
- "CS-144 Alternator" - No longer recommended as these alternators are bulky and somewhat hard to fit into the engine bay compared to the alternatives and ultimately aren't really any cheaper once modifications are made. Before discovery of the Denso 105A alternator, this was the go-to upgrade for the 5VZFE. At 120A idle and 140A highway, this GM-spec alternator provides 75-133% more power than the stock alternator. While the CS-144 is not bolt-in, and can be a bear to wrestle into the available space, the process of adapting it to the 5VZFE is reasonably straight forward. This option will require the following parts:
- An alternator
- ACDelco Gold 335-1048 Alternator
- local parts store: 1996 Buick Roadmaster V8
- A slightly different pulley for the alternator in order to properly align the belt. (241277 6-Groove Pulley For Delco CS144 Series Alternators Dimensions 21mm Belt x 56mm Rib OD x 17mm Bore)
- A wiring harness. There are two options here:
- Best: Purchase a purpose-built harness adapter that adapts the CS-144 alternator to the Toyota connector
- Cheaper: Adapt each alternator to a 4-pin trailer wiring harness - this is slightly cheaper but a little kludgier in that it converts the main wiring harness to a 4-pin trailer harness. Works well though if the purpose-built harness adapter is no longer available.
- GM CS-144 Wiring harness
- Two (2) sets of 4-pin trailer wiring harnessess - if desired, the CS-144 alternator and stock alternator wiring harnesses can be adapted to use a common trailer wiring harness connector. This allows either alternator to be installed by using the appropriate adapter, should the alternator fail on the trail.
- A longer alternator belt. Needed to loop over the larger pulley on the CS-144. Either Gates K040425 Micro-V Serpentine Drive Belt or Gates K040425HD FleetRunner Micro-V Serpentine Drive Belt.
- Washers - you'll need several washers to position the alternator in the mounting bracket
- An alternator
- DC Power 180A or 270A High Output Alternator - The price of these options (> $600) puts them out of reach of most, but if you need the power, this is the way to get it. As they are built specifically for the 5VZFE, they bolt right in.
High Output Alternator Wiring Upgrade
Upgrading your wiring is mandatory if you are upgrading the output amperage of your alternator. If you don't upgrade your wiring, it's only a matter of time before the additional current will lead to a fire.
Sometimes called the "Big 3" or "Big 4" or "Big 5" or even "Big 7" wiring upgrade, the idea is to increase the wire size between high-powered components in the engine bay in order to carry extra current, or to carry the same current with lower voltage loss.
- Big 3
- Alternator to Battery (+)
- Engine Block Ground to Battery (-)
- Battery (-) to Fender Ground
- Big "More" - depending on who is describing it - adds
- Battery (+) to Fuse Box
- Frame Ground to Battery (-)
- Starter to Battery (+)
- Cylinder Head Ground to Firewall Ground
Check out this guide for the various wiring upgrades:
Tools
Removing and installing an alternator is easy and requires almost no tools.
- 10mm, 12mm, 14mm, 19mm sockets and ratchet (this is a good kit)
- Torque Wrench - capable of 25 - 150 ft-lbs.
If you'll be installing a Denso 105A alternator, you'll also need:
- A drill - to drill out the a threaded hole in order to fit the tensioning assembly.
- 21/64 or 11/32 drill bit (this is a great set for future use, but not cheap)
If you'll be installing a CS-144 alternator (which is generally a bad idea 
you'll also need:
- Milwaukee M18 mid-torque impact wrench (2861-22) - if swapping out the pully on a CS-144 alternator.
- Soldering iron, solder, and heat shrink tubing.
- A ring terminal.
Doing the Job
Removing the Stock Alternator
- Disconnect the negative, then positive battery terminals.
- Remove the battery from the engine bay.
Give yourself room to work.
- Using a 12mm socket, loosen and remove the lock nut on the alternator tensioner.
- Using a 12mm socket, significantly loosen the alternator tensioner bolt but do not unscrew it all the way.
Loosening the alternator.
- Remove the alternator tensioner assembly from under the alternator (wiggle it out of the support bracket).
- Pivot the alternator toward the center of the vehicle and remove the belt from the pulley.
Belt removed.
- Using a 14mm socket, loosen and remove the alternator pivot bolt.
Removing the pivot bolt.
- Remove the alternator from the pivot mount and rotate it down into the engine bay / toward the frame rail in order to access the power cable and connector on the rear of the alternator.
- Using a 10mm socket, remove the nut securing the electrical power cable to the alternator.
- Remove the electrical connector from the rear of the alternator. Note: this connector can be difficult to remove. Press in from the side while wiggling the connector.
It's much easier to remove these from the alternator when it's not attached to the engine.
- Lift the alternator out of the engine bay.
Replacing Stock Alternator Brushes
Skip this section if you are simply replacing the alternator. The alternator brushes are located just under the back cover of the alternator and are easy to replace.
- Using a 10mm socket, remove the 3 nuts and 1 bolt that secure the rear alternator cover.
Accessing and exposing the brushes.
- Using a #2 Philips screwdriver, remove the two (2) screws that secure the brush assembly.
Worn out brushes (left) and new brushes (right).
- Insert the new brush assembly
- Tighten the two (2) Philips screws to hold the brush assembly in place.
- Replace the back cover and tighten the three (3) 10mm nuts and one (1) 10mm bolt.
Prepping the Denso 105A Alternator
Skip this section if you are not using the Denso 105A alternator.
The Denso 105A alternator needs to have the threaded hole that the tensioning assembly passes through drilled out to remove the threads.
Front comparison of Denso 105A alternator (left) and stock alternator (right).
Rear comparison of Denso 105A alternator (left) and stock alternator (right).
Denso 105A alternator tensioning assembly hole (left) and stock alternator (right).
- Using a 21/64 or 11/32 drill bit, drill out the threaded hole that the tensioning assembly passes through.
Making room for the tensioning assembly to slide through.
Prepping the CS-144 Alternator
Skip this section if you are not using the CS-144 alternator.
Installation of the CS-144 alternator requires a bit of prep - both to the alternator and engine bay - in order to get everything to fit when the alternator is bolted in. The following must be done:
- Replace the pulley in order to keep the belt properly aligned.
- Install a longer alternator belt.
- Adapt the connector on the CS-144 alternator to the 5VZFE wiring harness and to replace the belt with one long enough to capture the larger pulley of the CS-144.
Replacing the CS-144 Pulley
Pulley replacement isn't always necessary, but verifying that the correct 6-groove pulley is installed is important to ensure long belt life.
- To check whether you need to replace the pulley, place the stock alternator and CS-144 alternator pulley-down on a flat surface.
Pully mis-alignment.
Correct pulley on the right has a larger shoulder on the alternator side, pushing the front face of the mount up slightly in the previous photo.
- Compare the forward-facing surface of the mounting bracket.
- If the forward-facing surfaces of the mounting brackets are not aligned, you need to replace the pulley on the CS-144 with the updated 6-groove pulley in the parts section above.
- Wrap a rag around the pulley and fit the appropriate size impact socket over the pulley nut.
- Using an impact wrench, pulse the nut until it loosens; then remove the nut, washer, and existing pulley.
Removing the pulley nut.
- Place the new pulley, onto the spindle, followed by the washer, and nut.
- Wrap a rag around the pulley and fit the appropriate size impact socket over the pulley nut.
- Using an impact wrench, pulse it several times until the nut is secure on the spindle.
- Place the stock alternator and CS-144 alternator pulley-down on a flat surface to verify that the forward-facing surfaces of the mounting bracket are aligned.
Installing a Longer Alternator Belt
In order to install a longer alternator belt, you must remove - and then reinstall - the power steering and A/C belts.
- Loosen (don't remove) the 14mm pivot bolt and 14mm adjuster lock nut for the power steering belt (top-most passenger pulley)
Removing the power steering belt.
- Loosen 14mm adjuster bolt (access may be easier from bottom of engine).
- Once the two bolts are loose enough, pivot the pulley in and remove the belt.
- Loosen (don't remove) the 14mm nut that holds the AC idler pulley on
- Loosen (don't remove) the 14mm tensioning bolt for the AC idler pulley.
Removing the AC belt.
- Once the two bolts are loose enough, remove the AC belt.
- Remove the original alternator belt.
- Install the longer belt for the CS-144 alternator.
- Fit the AC belt. Tension the belt until the it is under the proper tension. Proper tension is approximately 1/2" of deflection at the mid-point of the belt.
- Tighten the pulley nut. Torque to 29 ft-lbs.
- Fit the power steering belt. Tension the belt until the it is under the proper tension. Proper tension is approximately 1/2" of deflection at the mid-point of the belt.
- Tighten the power steering adjuster lock nut. Torque to 32 ft-lbs.
Prepping the Wiring Harness
Skip this section if you've purchased the purpose-built harness adapter, as it will directly plug into the CS-144 as well as the Toyota wiring harness. Good job spending a few dollars on the correct solution.
If you plan to convert the engine wiring harness to use a 4-pin trailer harness, and then two small adapters to adapt the CS-144 and OEM alternator to the trailer harness, follow these steps.
- Cut the plug off of the OEM alternator wiring harness, leaving enough length of wire on each side of the cut in order to solder on the trailer harnesses. Generally, this means leaving about 1-inch of wire coming out of the plug.
Work on the OEM alternator adapter first, in order to ensure that the wires from the original wiring harness are aligned correctly.
- Plug the OEM alt plug into the OEM alternator.
- Solder and heat shrink the OEM alternator plug to the male trailer wiring harness. Note: only the three exposed pins on the trailer wiring harness will be used.
- OEM alt white (sense wire) - exposed pin on edge of trailer wiring harness.
- OEM alt red (ignition wire) - middle exposed pin of trailer wiring harness.
- OEM alt yellow (activation wire) - exposed pin next to the insulated terminal of trailer wiring harness.
- Cut off the unused wire for the insulated terminal of the trailer wiring harness.
- Solder and heat shrink the engine side wiring harness to the female trailer wiring harness. Note: only the three insulated terminals on the trailer wiring harness will be used, and should result in the OEM wiring "aligning" on either side of the trailer wiring harness plugs.
- Engine side white (sense) - insulated terminal on edge of trailer wiring harness.
- Engine side red (ignition) - middle insulated terminal of trailer wiring harness.
- Engine side yellow (activation) - insulated terminal next to the exposed pin of trailer wiring harness.
- Cut off the unused wire for the exposed pin of the trailer wiring harness.
OEM to trailer harness adapter.
Create the adapter for the CS-144 alternator.
- Plug the GM CS-144 Wiring harness into the CS-144 alternator.
- Crimp, solder, and heat shrink a ring terminal onto the end of the thick red wire (sense).
- Attach the ring terminal to the positive post on the alternator.
- Solder and heat shrink the GM wiring harness plug to a male trailer wiring harness. Note: only two of the three exposed pins on the trailer wiring harness will be used, an only three of the GM alt wires will be used.
- Middle wire on GM alt closest to thick red wire - middle expose pin of trailer wiring harness (ignition).
- Middle wire on GM alt furthest from thick red wire - exposed pin next to the insulated terminal of trailer wiring harness (activation).
- Edge wire on GM alt opposite from thick red wire - unused; cut off this wire.
- Cut off the unused wire for the exposed pin on edge of trailer wiring harness.
- Cut off the unused wire for the insulated terminal of the trailer wiring harness.
GM to trailer harness adapter.
Prepping the Alternator Pivot Mount for Installation
The alternator pivot mount has a small sleeve in the front hole that must be "reset" before the alternator will slide into the bracket.
- Place a 19mm socket over the front hole of the pivot mount.
- Insert a bolt through the 19mm socket and alternator pivot mount. Thread a nut on the back side that is larger than the hole in the pivot mount.
- Using a wrench, tighten the bolt against the 19mm socket until the nut on the back side of the pivot mount pulls the sleeve flush with the back side of the pivot mount and a few millimeters into the 19mm socket.
Resetting the sleeve by pulling it forward in the alternator mount.
Installing the Alternator
With the pivot mount sleeve reset, installation of the alternator is the reverse of removal.
- Place the alternator into the engine bay with the pulley facing down.
- Ensure that the orientation will be correct as the alternator is rotated into position and then plug in the electrical connector.
- Using a 10mm socket, secure the electrical power cable (or adapter harness) to the alternator, ensuring that the orientation will be correct as the alternator is rotated into position. Tighten to "good and tight."
- Rotate the alternator into position between the pivot mount.
- Insert the pivot bolt and begin threading it into the rear mount, but do not tighten it. Note: CS-144 alternator only: When inserting the pivot bolt, fill the gap between the alternator and rear mount with washers prior to pushing the pivot bolt through.
- Insert the alternator tensioner assembly into the tensioner bracket and the tensioning hole on the alternator.
- Loosely thread the nut onto the alternator tensioner assembly. Do not tighten.
- Loop the belt over the alternator pulley. Note: CS-144 only: the pulley has 6 grooves rather than four. Choose the grooves that result in the belt being properly aligned with the pulley on the crank shaft harmonic dampener. Usually, the belt sits on the front/out four grooves of the alternator pulley, leaving those closest to the alternator empty.
- Tighten the alternator tensioner bolt until the belt is under the proper tension. Proper tension is approximately 1/2" of deflection at the mid-point of the belt.
- Using a 12mm socket, tighten the tensioner lock nut to 25 ft-lbs.
- Using a 14mm socket, tighten the pivot bolt to 38 ft-lbs.
Alternator installed - in this case, a Denso 105A alternator.
Reinstalling the Battery
- Place the battery in the engine bay.
- Using a 12mm socket, secure the battery using the battery clamp.
- Reconnect the battery; positive terminal, then negative.
- Start up the truck and verify that
- The belts are tensioned correctly.
- The alternator is generating ~14.2 - 14.7v.
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