Repairing Guides

how to repair alternator

by Floyd Grant Published 3 years ago Updated 2 years ago
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There are three options for you to choose on how to repair alternator:

  • Replace your old alternator with a new one
  • Replace your old alternator with a used one
  • Repair your old alternator

Full Answer

How do you tell if the alternator needs replacing?

The Warning Signs of a Failing Alternator

  • Indicator Lights. Most modern cars have a dashboard warning light to alert you to a problem with your alternator. ...
  • Headlight Trouble. Your alternator provides the power to your headlights. ...
  • Other Electrical Problems. ...
  • Smells. ...
  • Dead Battery. ...
  • Stalling or Difficulty Starting. ...
  • Noises. ...

How much does it cost to get your alternator rebuilt?

There are also rebuilt alternators. These are alternators in which only the components which show visible wear and tear are replaced. A rebuilt alternator will only cost you $80 to $150 for the rebuilt charge.

How to easily diagnose a bad alternator at home?

  • Start the vehicle (it'll start and stay running if you have charged the battery.)
  • Put the red multimeter test lead on the battery positive terminal.
  • Put the BLACK lead on the battery negative terminal.
  • Look at the reading. It should hover around 12 Volts.

How to make replacing an alternator easy?

In addition to a replacement alternator, you’ll need some tools:

  • Hand tools like ratchets, sockets, and wrenches
  • Belt tensioner tool
  • Gloves and safety gear
  • Battery tender or memory saver, if necessary
  • Jack, jack stands, and wheel chocks, if necessary

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Can you repair an alternator?

Rebuilding an alternator is a fairly simple procedure, which anyone with basic automotive knowledge can accomplish. Although the construction of some brands will vary slightly, the basic anatomy of an alternator consists of the same components. Follow these steps as you learn how to rebuild an alternator.

How can I make my alternator work again?

2:554:34How to Fix a Dying Alternator for Free - YouTubeYouTubeStart of suggested clipEnd of suggested clipBut you don't have to hit it hard you don't have to beat the living crap out of it. But. If you doMoreBut you don't have to hit it hard you don't have to beat the living crap out of it. But. If you do it. Right. You'll get your alternator to start working again.

How do you fix an alternator that is not charging?

Check the large power cable to the alternator and the fuse, usually, a large 40-60 amp fuse near the battery. Check the ground cable between the engine and the body. Check the serpentine belt and make sure the alternator is spinning with the engine. Check the small power supply wire and the charging light wire.

Can cleaning an alternator make it work again?

The process involved is pretty easy, and you do not need any sophisticated tool for cleaning the alternator. With water and a degreaser (water-soluble), you can make your vehicle's alternator look as new, getting rid of all contaminants.

What kills an alternator?

Running in full charge mode continuously can kill an alternator, so trying to have your new alternator try and charge your dead battery can result in immediate alternator failure.

What causes alternator failure?

Most of the time, alternators fail as a result of age or use. However, some other factors can cause an alternator to fail prematurely. Fluid leaking on the car alternator can commonly lead to failure. Often, engine oil or power steering fluid can work its way into the alternator and cause it to malfunction or fail.

Which fuse is for alternator?

But when someone mentions the “alternator fuse”, they're generally referring to the primary, high-amperage fuse (or fusible link) between the alternator and the battery. Like any fuse, the primary alternator fuse acts as a circuit protection device.

How do you diagnose an alternator problem?

7 Signs of a Failing AlternatorDim or Overly Bright Lights. ... Dead Battery. ... Slow or Malfunctioning Accessories. ... Trouble Starting or Frequent Stalling. ... Growling or Whining Noises. ... Smell of Burning Rubber or Wires. ... Battery Warning Light on Dash.

How do I know if my alternator fuse is blown?

0:261:57Car Battery Dead? Check Your Alternator Fuse - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo if the fuse is bad it's most likely gonna have physical signs of burning or melting.MoreSo if the fuse is bad it's most likely gonna have physical signs of burning or melting.

Does tapping on alternator work?

Some people believe that you can just tap the alternator with a hammer to get it to operate. You should not do this because it will damage the part and you might even damage the surrounding parts to the car, resulting is a large car repair bill.

Can you spray water on your alternator?

Car alternators are NOT waterproof. Considering how the alternator is built to function, it is almost impossible to waterproof it. Most alternators are air-cooled, with air being drawn through the alternator by an internal fan which is attached to the drive end of the alternator shaft.

How do I clean the inside of my alternator?

5:0713:33Demonstration of Alternator cleaning with Awesome! - YouTubeYouTubeStart of suggested clipEnd of suggested clipThat's what I like about this oh yeah puts it do this with gloves I'm not doing the gloves because IMoreThat's what I like about this oh yeah puts it do this with gloves I'm not doing the gloves because I got a dual it down so it's not so bad but use it straight I'll make skin peel a little bit.

Tips

When installing a new volt regulator, be sure to apply thermal grease to the back of the apparatus.

About This Article

wikiHow is a “wiki,” similar to Wikipedia, which means that many of our articles are co-written by multiple authors. To create this article, 11 people, some anonymous, worked to edit and improve it over time. This article has been viewed 331,128 times.

Step 1: Before You Start, Purchase the Right Kit for Your Alternator

The assumption is that you have already purchased a brush and regulator replacement kit for the model of alternator you have before starting this instructable.

Step 2: Safety First, Disconnect the Car Battery

Disconnect the +ve from the battery for safety, I actually did not do this and bumped a +ve wire connected on the Alternator which created some brief fireworks, so my advice is to disconnect the +ve on the car battery first.

Step 3: Remove the Alternator

Take some photos of the alternator in position and the orientation of the wire harness, ie the wiring socket at the rear of the alternator. Before unbolting the alternator ensure you unclip the wire harness on the rear of the alternator.

Step 4: Remove the Rear Cover on the Alternator

Now you have removed the alternator, remove the plastic cover on the rear of the alternator, typically there are two bolts to be removed to remove the cover.

Step 5: Remove Old Regulator and Brushes, Fit New Kit

With the rear cover on alternator removed, take some photos of the regulator, and wiring to and from the regulator and the brushes. These maybe handy should you have issues refitting the wiring.

Step 7: Refit the Alternator

Refit the alternator back into your vehicle and make sure the fan belt is tight.

Step 8: Now Run Some Tests to See If You Have Fixed It

Attach your multi-meter +ve to car battery +ve and multi-meter –ve to car battery –ve, set the multi-meter voltage range to 20VDC or the next above whichever is available on your multi-meter.

How to repair an alternator?

There are essentially three ways to make an alternator repair (either by the mechanic or yourself): Replacing the old alternator with a brand new one. Replacing the old alternator with a used or refurbished one. Refurbishing (repairing) your old alternator. More on this topic and how to make a proper choice lower in the article.

How long does an alternator last?

A refurbished or repaired alternator (if the repair is done in quality) should last at least 100.000 kilometers without any problems. Almost all parts can be bought separately and are meant to be replaced. The only limiting factor for this solution is the build of the alternator itself.

Why does my alternator snap?

10. Snapped or damaged serpentine belt. In case of an alternator repair, serpentine belts can snap or get damaged for two reasons: either its worn out or the alternator pulley is jammed. The snapping can happen at a moments notice or a screeching sound may previously appear.

Why does my engine make a screeching noise?

Main reasons for this can be: Front bearing is worn out which means the rotor gets stuck and the serpentine belt slides over the pulley.

What does it mean when an alternator makes a grinding noise?

4. Grinding noise from the alternator. When a grinding noise appears it is almost certain that the bearings have worn out. There are two bearings, one in the front housing and one in the rear; these bearings hold the rotor in center.

Where is the alternator located on a car?

Here the biggest problem could be accessibility to the alternator itself. On most cars the alternator is located in the upper part of the engine, in a visible and easy-to-reach part of the engine bay.

Should I buy a refurbished alternator?

Buying a refurbished one is the next best thing to a new alternator. For this option, do it if the price is significantly lower than the cost of a new one. Just have in mind the longevity of repair as a refurbished or worse, used one, probably won’t last as long as a new alternator.

How much does it cost to fix an alternator?

How much do alternator repairs cost? It depends if a repair is possible. If not, you’ll have to have it replaced, which can run between $500 to $1,000 (including parts and labor). Otherwise, for something simple like replacing an alternator belt, expect to pay about $100-$150 (not including diagnosis).

How does an alternator work?

How An Alternator Works. Simply put, an alternator converts mechanical energy, which is made by your engine, into electrical energy. Components like your AC, power steering, power windows, and radio, can’t run on mechanical energy. Instead, they need electricity, which is why the alternator is so crucial.

Why does my alternator make a whining sound?

As stated previously, your alternator runs off a belt that’s connected to the crankshaft. If you begin to notice a whining or growling sound coming from under the hood, it signals there might be an issue with the system. These include a damaged or misaligned belt or worn bearings.

Why is an alternator important?

Instead, they need electricity, which is why the alternator is so crucial. You might think your battery handles this, but in truth, it’s only in charge of getting your car started in the first place. This means that the battery starts the engine, and the alternator keeps it going.

What does 12.2 mean on a car battery?

12.6V is the magic number, it should not drop far below this range. Anything below 12.2 means your battery is only half-charged. If it is far above, then there is a problem that may lead to a blown alternator or battery. If it is low, unhook the battery from the car and attach it to a charger.

What is a voltage regulator?

Voltage Regulator. You can think of the voltage regulator as basically a surge protector for the alternator, controlling the amount of power it creates. If there’s too much electricity being sent, it can damage the different components. Yet, if there’s not enough, they won’t be able to operate.

Does a new alternator come with a warranty?

Obviously, a new alternator will cost the most, but it is sure to last the longest. Thankfully, either a new one or a refurbished one should come with a warranty.

What does an alternator do?

The alternator plays a vital role in supplying power to the car’s AC, recharging the battery and ignition. When your alternator is faulty, the battery power is drained fast, and you will find yourself with a stalled car. But what can cause the alternator to go bad? Table of Contents.

How to check alternator charge?

Diagnosing an alternator that won’t charge 1 Tap the alternator carefully with a hammer while the engine is running; if the charging goes back to normal, the carbon brushes inside it are worn out and need a replacement. 2 Check the large power cable to the alternator and the fuse, usually, a large 40-60 amp fuse near the battery. 3 Check the ground cable between the engine and the body. 4 Check the serpentine belt and make sure the alternator is spinning with the engine. 5 Check the small power supply wire and the charging light wire. You can measure it with a multimeter, but you might need a wiring diagram and some car electronic skills to do this correctly. 6 You can measure the diode assembly and the voltage regulator to make sure they are not damaged. You can replace these with some alternators, but it is often the same price to buy a new alternator nowadays. It is up to you what you think is more worth it.

Why is my alternator not working?

Sometimes there is an electrical problem in the alternator, and even if the voltage does not change, it might be damaged. Another common cause is a bad diode plate or a voltage regulator. You might need some knowledge about alternators to replace these in most cases.

How many wires does an alternator have?

An alternator does usually has 3 or 4 wires to it to function properly. You will find one big main cable together with two or three small ones. All these wires are important for the alternator’s function, and if one breaks off – you might lose the charging function.

What happens when the serpentine belt fails?

The serpentine belt powers the alternator, and if it fails, the alternator will stop working the moment your belt wears out and breaks, or the pulley becomes damaged. This can also happen if the serpentine belt ...

Why is my car not charging?

The most common reason why your car is not charging is actually because of a worn-out or damaged alternator. You can carefully tap it with a hammer while the car engine is running while checking it with a multimeter on the car battery to see if the voltage is changing. If the voltage change and go back to normal when you tap it lightly ...

Is it worth replacing an alternator?

It was more common to replace parts inside the alternator like the carbon brushes, diode plate, or voltage regulator on older cars. Nowadays, alternators are quite cheap, and mostly it is more worth to replace the whole alternator.

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