how to repair car 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

Full Answer

How do you rebuild an alternator?

When you turn the ignition key and there’s no battery warning light at all you should check:

• Voltage regulator (namely the brushes on it)
• Connection to the alternator
• Commutator on the rotor (is it damaged or worn out)
• Rotor; namely the coil inside (this one is really rare)

How to rebuild car alternator?

take out the old alternator and insert the new one in place (make sure to align it with the anchors) turn on the car and see that everything works properly (like there is a battery warning light when you turn the ignition, that it turns off when you start the engine, there are no strange noises etc)

Can You rebuild 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. Disconnect the battery leads.

How to fix a dying alternator for free?

• Check the battery. If you have a multimeter, you can check the voltage – but this only tells you so much. ...
• Check the alternator. Yes, you think it’s okay, but did you check it the right way? ...
• Check for a parasitic draw. ...
• Make sure your alternator’s wiring is right to go. ...

Can alternator be repaired?

Alternators are simple machines & can certainly be repaired. You need to ask them exactly what part of that alternator has failed and that part can be replaced. For e.g. the alt may be mechanically sound but the brushes are worn out or the rectifier, regulator may have failed.

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 the battery?

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.

What causes alternators to stop working?

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.

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.

Can a car run without an alternator?

For the unfortunate souls who realize that this vital part of the vehicle is failing, how long will a car run without an alternator and what can you do to elongate the vehicle's ability to function? Without this essential component, your car will only function for up to two hours and as little as five minutes.

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 you tell if its your battery or your alternator?

If the engine starts but dies immediately, your alternator probably isn't keeping your battery charged. If a jump starts and keeps your car running, but the car can't start again off of its own power, a dead battery is probably your answer.

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.

How much is a new alternator?

Labor costs vary as well, since some alternators are easier to get to and thus take less time, but expect to pay between $200 and $600 for the labor. All together, expect to pay somewhere in the range of $350 to $900 total for an alternator replacement.

Can you jump an alternator?

You actually can jumpstart a car with a bad alternator, and the car will keep running for some time, no matter how bad the alternator is, well, considering you have a good battery. This is because if the alternator is bad and not producing the voltage required, the car will be running purely off the battery.

Is there a fuse for a alternator?

Most of the time, there's a high-amperage fuse or fusible link between the alternator's battery terminal and the battery. Also, there are usually low-amperage fuses in series with the alternator's sense terminal and ignition terminal.

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.

Tips

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

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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.

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.

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.

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.

What does high voltage mean in a car?

If it is, it can seriously damage the car battery and the electric installation and components. High voltage means checking the: Voltage regulator. Alternator stator (if it’s burnt out) A word of warning: before starting any kind of repair, let the fumes out from the engine bay as they are flammable. 9.

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.

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 ...

What is the ECU in a car?

In this regard, the engine control unit (ECU) controls most of the car’s electrical components. Modern cars also control the alternator. In some rare cases, there might be a problem with the engine control module not controlling the alternator’s charging.