How to repair Car Air Conditioning?

What is “Black Death”?

While Black Death is not the same as the deadly plague during the 14th century, a car A/C system experiencing Black Death will be infected like the plague. Black Death starts out inside the compressor after refrigerant breaks down. Since refrigerant acts as a working fluid much like how motor oil is the fluid which provides lubrication to protect the engine, a refrigerant breakdown will result in ugly wear, starting in the compressor. From there, the sharp and grimy metal particles created during compressor breakdown can then travel through the rest of your A/C system, wreaking havoc on the entire system. Before you know it, all cold air, and airflow for that matter, will be long gone. Cue the A/C grim reaper

Why does my A/C have weak airflow?

We feel your pain and discomfort caused by weak airflow. The sweat alone is enough to drive any of us crazy. However, there are a lot of factors at play. If you notice reduced airflow early on –rather than later– take the right step and have it looked at before other fatal A/C system damage can occur.

Main causes of weak airflow:

• Mold or mildew may have accumulated in the evaporator core from residual moisture that occurs during the cooling process. When this happens, air will have trouble reaching your air vents.
• A hose has come loose. This usually happens with the blower hose that supplies air to the blower unit.
• Ventilation fan is fried. If the fan’s not blowing, air won’t be flowing very well.
• Seals. No, not those seals down by the pier. Core case seals, blower house seals or evaporator core case seals; All can open up and diminish air flow. A/C ventilation systems are very sensitive and must remain sealed. Once they’re opened, the whole system is compromised..

Are there any system warning lights to alert me to an A/C problem?

Typically, no, but some vehicles have Driver Information Centers (DIC) that may display the status of many vehicle systems. Refer to your Owner’s Manual for more information.

My A/C isn’t as cold as it used to be, what’s going on?

There are several reasons an A/C system can lose its cool. Bring your ride to us as soon as you start noticing this symptom, it could mean the difference between needing a small repair, or worse, a large one. Here’s what can cause your cold air to lose its cool.

The lack of precious cold air could be caused by:

• A Freon leak caused by a failed o-ring, seal, hose or component
• A clogged expansion tube or refrigerant charging hose
• Failed compressor or compressor clutch
• Failed blower motor or blower motor resistor
• Damaged or failed condenser or evaporator
• Vacuum leaks
• Failed switch, fuse, relay, control module, blend door or solenoid

Leaks can be devastating. When an A/C system develops a leak, you have what’s called an “open system.” If you or your technician discovers the leak early, your repair will be less expensive. Unfortunately, if a leak has been affecting your cold air for a while, moisture will most likely have entered your A/C system and may have damaged other vital and expensive parts. Stay cool.

The A/C starts out cool then starts getting warm, what’s happening?

Well, like many complicated stories, there’s never one simple answer. A/C systems are a fickle breed. Your best bet is to have us inspect your system for any of the following listed symptoms.

From cold to hot and all the symptoms in between:

• The clogged expansion valve: The expansion valve distributes the proper amount of refrigerant to your evaporator. If the valve is blocked, the refrigerant can’t flow into the evaporator. With the valve clogged, the refrigerant will start to freeze the valve altogether if moisture is present.
• Faulty compressor clutch: If the clutch is not engaging with your compressor, than your compressor can’t maintain the correct pressure. Hot air will result.
• The blown fuse scenario: Fuses sometimes short out. If the fuse associated with your A/C system goes, the power to certain parts will stop.
• Leaks are an A/C system’s worst friend: Leaks are the result of damage or the presence of moisture. When moisture and refrigerant mix, nasty corrosive acids will eat away at seals and components, causing a leak.

What is the smelly, gym locker odor coming from my A/C vents?

Sounds like you have an odorific problem on your hands. There are a few issues that may be causing this smell.

Potential causes of nasty “gym locker” odors:

• Dirty and old air cabin filter.
• Moldy evaporator case. A problem for many vehicles when water sits in the evaporator case because the case’s drain is blocked. Mold will accumulate.

How do you test for an A/C system leak?

While we’re no C.S.I. unit, the ways to detect an A/C system leak are not far off from an episode of the ever popular investigation show.

Detecting leaks:

• Black light enabled dyes. You read that right. A lot of refrigerants are pre-mixed with a special U.V. dye that shows up under black light. We’ll run a black light over your A/C system to see if any dye shows up.
• Bring in the “sniffer.” A sniffer is a special device that hones in on the refrigerant’s chemical components. If there’s a leak, our sniffer will sniff it out.

What causes an A/C system leak?

Age and moisture. Plain and simple. Rubber seals and hoses can also lose their elasticity over time and breakdown allowing Freon to escape and moisture to enter your vehicle’s A/C system. Moisture is the kiss of death for your A/C system, mixing with refrigerant and creating a system destroying corrosive acid.

Quick fact: If moisture is present, it could damage your accumulator, receiver or drier. Remember, these devices are responsible for removing moisture from the A/C system and will eventually stop functioning once they are exposed to an open system (leak or crack).

edited by DNT Tools

How to Remove Windshield &Auto Glass

Sometimes it is best to R & R (remove and replace) glass for a repair. This article will demonstrate how to remove a windshield, quarter glass and instructions for other automative glass, whether you need to repair or replace it. One of the limitations of refinishing around glass openings is achieving a good masking of the weatherstripping without the tell-tale line of paint where the masking tape covers the weatherstrip. When doing a total restoration of an older car (such as a Ford Mustang), the only way to achieve a perfect paint job around the glass openings is to remove the glass.

Glass Definitions

First, let’s clear up the words. The front glass is called the "windshield" here in the USA (the British call it the "windscreen"). The rear glass is not called the "rear windshield". It is called the "back light".

Then there is the "door glass" for windows that retract into the doors. Lastly, there is the "quarter glass" as found on 2-door coupes. Quarter glasses can either retract like door glass or open outwards at the rear by means of front hinges. They can also be stationary (like in a Volkswagen Beetle).

Two Ways To Mount Automotive Glass

Other than mounting quarter glass with screws (such as in the Honda Civics and Accords), there are two ways glass is usually mounted in the vehicle.

Windshields, back lights and quarter glasses are mounted to the body shell to a mating flange where the inner and outer body panels are welded together.
One way the glass is mounted is with rubber weatherstripping to hold the glass in place.

Weatherstripping sometimes comes with strips of metal trim which is inserted after the glass and weatherstrip is installed. Sometimes these trim pieces actually wedge the glass and weatherstrip to help hold them into place.


The other way is where a water-tight adhesive is used to glue the glass in place. This adhesive takes the place of overlap both the body panels and the glass. In this case the glass contributes to the overall structural integrity of the car. In most modern unibody cars this is the usual method of mounting glass.

Replacing Automotive Glass Using Adhesive

Once the body panels have been refinished, replacing glass held in place with adhesive is a straightforward process. First, fit the glass to the opening to make sure there is a perfect fit. If necessary, continue with sheet metal straightening before refinishing the panels until the glass fits perfectly. Obtain a caulking gun and a tube of windshield adhesive (such as one manufactured by 3M) obtainable at your local refinish supply house.

Make sure that both the glass and the body panels have been thoroughly cleaned to remove all contaminants and old adhesive so a perfect water-tight seal is attained. Apply the adhesive to the mating flange on the body panel evenly so there is an unbroken bead all the way around the glass opening.

Carefully place the glass onto the opening and press it down so the bead of adhesive spreads slightly. Make sure to allow room for the trim pieces. There are spacers designed for this purpose which can be obtained. Let the adhesive set for the recommended time. Then reinstall the trim pieces.

Remove Quarter Glass

Removing and replacing glass held in place by weatherstripping is a little more straightforward. Let’s use an example of a quarter glass first. Quarter glass can easily be removed by one person without breaking.

From the inside of the car and using the thumbs and forefingers, start by gently working out the lip of the weatherstrip on a corner of the quarter glass. Proceed from this corner around the quarter glass gradually working out the lip while gently pushing the quarter glass outward. Work all the way around the quarter glass in this manner to first loosen the lip of the weatherstripping.

Finish Removing Quarter Glass

Select a rounded corner of the quarter glass as a candidate for pushing the glass and weatherstrip out and push out this corner to dislodge the weatherstrip from the sheet metal mating flange.

If the glass doesn’t dislodge without flexing, you have to work the lip out more before pushing. Don’t force it or you will break the glass.

Once you have worked a corner completely out, it is easy to finish the job. Gradually pull the lip of the weatherstrip away from the mating flange from both directions of the pushed-out corner. The glass will come completely out with the weatherstrip attached to it.

Remove Windshield

Removing the windshield is a little trickier than quarter glass. First, it’s bigger and it is usually curved. Second, sometimes this requires an assistant to help. Start by removing any trim pieces on the weatherstrip that may be wedging the weatherstrip in place. Also remove any interior trim from around the glass. Start by loosening the lip of the weatherstripping all the way around from the inside of the car as with the quarter glass.

You will be using your feet to dislodge the glass. Adjust the front seats and assume the position shown in the diagram. You will be pushing both top corners at the same time. If you have used enough silicone lubricant and loosened the weatherstrip enough, the top two corners will pop out.

Car Repair Question: Noise Diagnosis for Axle Shaft Bearings

Rear Axle Shaft Bearings

Luckily diagnosing axle shaft bearings does not come up very often, because the sounds they make can be mistaken for other drive train problems..

Even a noisy tire with choppy tread can be mistaken for a defective bearing. This article talks about rear axles, seals and bearings. Not to be confused with a standard hub wheel bearing that a rim and tire attach to.

Generally speaking front wheel drive vehicles have rear sealed hub bearings. they often contain ABS wheel speed sensors and can be expensive.

Rear wheel drive vehicles with pumpkin style differentials and solid axles have axle bearings. They are inexpensive but labor intensive to replace and diagnose.

Many vehicles go to the junkyard with the original axle shafts and bearings. If the rear differential is serviced properly and the fluid level is maintained, this will in turn lubricate the bearing.

Periodic inspection of your rear differential and checking fluid level is a good maintenance routine to get into and can save you a lot of trouble as the automobile ages.

Some of the key areas that fluid can leak from are the rear differential pinion seal as well as the axle seals.

When axle seals begin to leak the heavy gear oil can be dispersed onto your rear brake shoes or pads and rotors or drums. This can reduce braking efficiency as well as create noise and possibly a burning odor.

Types of Axle Shaft Bearings

There are three major bearing designs used in cars and trucks. There is a ball type, straight roller and a tapered roller style.

Regardless of the type utilized the main function is to support the vehicle’s weight, reduce rolling friction by allowing the wheel to spin freely.

A visual inspection of the bearing in most cases is not possible until you slide the axle out of the differential housing. In some cases its obvious how the axle is held into the differential housing.

In many Ford applications you will see bolts that hold a flange against the differential tube. Removing these bolts allows the axle to slide out. On GM vehicles it is more common to have the shaft retained in the differential carrier.

On these types of set ups you have to remove the differential cover then remove the pinion shaft. Next push the axles towards the center to reveal and remove a C clip retainer.

With the C shaped clips removed they will easily slide out of the differential housing. When replacement is needed, often the axle bearings are pressed onto the shaft using special equipment and holding fixtures.

Many auto parts stores will provide this service for free if the replacement parts are purchased at the store. You should also replace the axle seals at the same time. The parts store shouldn’t let you walk out the door without new seals.

Diagnosing Bearing Failure

With the axles removed as described above you can perform a visual inspection of the shaft bearings and look for scoring, burn marks or even pitting or chips on the individual rollers.

Most often when lack of lubrication causes bearing failure you can actually see heat damage in the form of bluish or purple marks on the rollers.

When it comes to diagnosing defective parts in any drive-train system a good diagnostic road test should be performed before dis-assembly occurs.

This can often point you towards a suspect part. It may also eliminate other items that can be mistaken for axle shaft bearing noise. Bad axle bearings often make a growling or rumbling sound at highway speeds.

Changing lanes may cause the noisy bearing to either increase or decrease the noise level. An example is if you are in the center lane and you move to the left lane.

Additional weight is put on the right rear. An increase of noise from the right rear during that lane change may indicate an inspection of the right side is necessary.

These types of lane changes and diagnostic methods should only be used in a safe manner. Preferably on a quiet road way with no other traffic around you.

Making drastic lane changes could be considered reckless driving and an accident is highly possible. It wouldn’t make any sense to wreck a perfectly good vehicle just to find out what bearing is noisy.

HOW TO FIX BLACK SMOKE?

HOW TO FIX BLACK SMOKE?
Begin with the vehicle on level ground, parking brake set while wearing protective eye wear and glove

Step 1 - If the check engine light has illuminated the PCM has detected a malfunction that could be causing the black smoke such as a shorted fuel injector

Step 2 - When a fuel pressure regulator fails it allows raw fuel to enter the engine producing black smoke.

Step 3 - A stuck or shorted fuel injector can allow too much fuel to enter the engine.

Step 4 - Occasionally a computer can malfunction holding the injector drivers open longer than it should, causing an excess of fuel producing the black smoke.

Step 5 - A bad computer system ground can lead to a malfunction that can include allowing too much fuel to enter the engine producing black smoke, inspect wiring harness grounds at the battery and engine.

Step 6 - On older engine's inspect under the hood for vacuum leaks which can cause the computer to malfunction creating black smoke.

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HOW TO FIND A VACUUM LEAK?

Easy step by step guide on how to detect and fix an automotive engine vacuum leak, this information pertains to most vehicles.

Begin with the engine cool on level ground with the emergency brake set, also wear protective eye wear, gloves and clothing. Carburetor cleaner is flammable so use caution when testing, have a fire extinguisher ready. (Note: Never spray exhaust manifolds.)

Step 1 - Inspect vacuum hoses for dilapidation or cracks, this will cause the engine to stall, idle poorly and hurt gas mileage.

Step 2 - Vacuum lines can become hard due to under hood temperatures which produce an unwanted vacuum leak.

Step 3 - After removing the old vacuum line and check for blockage, install a new replacement hose, this can be done by using vacuum or fuel hose.

Step 4 - If after inspection, no broken vacuum lines are found carburetor cleaner can be used to further inspect for leaks.

Step 5 - After starting the engine and allowing it to idle, spray the cleaner near and around the throttle bore gasket, if the gasket has failed the engine will react to the spray by increasing the engine idle speed as the cleaner is burned. If the engine is idling rough it will temporarily smooth out as the cleaner is consumed

Step 6 - Continue testing by spraying around the intake manifold plenum and base gaskets while observing engine speed, if the gasket has failed the engine speed will increase.

Step 7 - Moving on to external components such as EVAP control solenoids, valves and connections while still observing engine speed.

Step 8 - A large amount of vacuum is used to work the brake booster and can allow major leaks, spray around the booster while observing engine speed. Also, an audible hissing noise can sometimes be heard coming from around the brake pedal when the brakes are applied which also indicates the booster has failed. An alternative method of a vacuum leak inspection is to pinch a supply line to the accessory and observe engine speed, an increase indicates a leak.

Step 9 - Check small vacuum tubes for cracks and broken pieces, these tubes provide vacuum to many accessories such as the heater/air conditioner, leaks under the dashboard near the heater plenum can also occur.

Step 10 - Use a small piece of vacuum line to act as a connector which will repair the issue and return the heater/defroster/air conditioner to it proper operation.

Step 11 - A vacuum gauge or tester can be used to check an external system for additional leakage. This is done by disconnecting the vacuum tube from the vacuum source (engine) and attaching it to the tester. Pump the tester and observe the vacuum, it should hold vacuum if the system is working properly. (Note: A small amount of seepage is normal.)

How to replace a clutch?

This will show you a typical clutch replacement and help you with the little nuances which will give you the best result. A clutch is constructed using asbestos so use a mask before removing the clutch disc. Gloves and protective eyewear are a good idea as well. There will be several subsequent guides that will need to be performed before the clutch can be replaced which are listed below:
Jack up and support the car on jack stands
Remove the exhaust system (some models)
Remove the driveshaft (rear wheel drive)
Remove CV axle (front wheel drive)
Manual transmission removal
1. Remove the Clutch: Once the above jobs have been done it's time to inspect and remove the clutch pressure plate. The picture below shows what it looks like once the transmission has been removed which exposes the clutch assembly that is mounted onto the flywheel at the rear of the engine. Again this part deals with asbestos so an air mask is recommended.

The pressure plate will be held onto the flywheel by 10 12mm, 13mm or 14mm bolts in most cases. When you start to undo the bolts the flywheel will want to move and turn the engine over so you will need to break the bolts loose by applying leverage inward or outward from the flywheel. An impact gun also works well for this. Do not remove all of the bolts at once because the pressure plate traps the clutch disc which can be heavy and can fall causing an injury. As the last bolts are undone have an extra hand to control both the pressure plate and disc. The pressure plate will start to move outward from the flywheel as the the bolts are undone.
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While the last bolts are being removed keep your hands on the disc and plate to control these parts. Support the disc while using a finger which is a good method of holding the disc onto the pressure plate.

Once the bolts have been removed the pressure plate may still be held onto the flywheel with 3 or more alignment dowels. Gently work the pressure plate from the flywheel using a standard screwdriver until free.

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2. Inspect Clutch Wear: The clutch disc is the part that wears down much like a brake pad, in fact the clutch disc has brake pad material on either side of it which is held on by rivets. When this lining wears it allows the rivets to contact the flywheel or pressure plate which causes the clutch to slip.

3. Check the Flywheel: The clutch mating surface of the flywheel will now be exposed. You are looking for extreme heat checks, hot spots and cracks which are a sign the clutch was slipping for a long period of time and will warrant the flywheel's replacement. The flywheel below is what a the typical wear pattern looks like during a clutch replacement and can be re-machined which must be done anytime you are servicing the clutch. If this step is skipped when the new clutch is installed you will have a good chance that it will chatter when the clutch pedal is released and the job will need to be redone.

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4. Replace Pilot Bearing: On rear wheel drive and some front wheel drive cars the clutch will have a pilot bearing which is designed to support the input shaft of the stick shift transmission. If this bearing locks up or becomes worn out it allows the input shaft to wonder and will cause the clutch to not disengage. The pilot bearing should be replaced during the clutch service.

5. Match the New Clutch: Place the old clutch next to the new clutch on a table. Check the diameter of the disc and the surface area of the clutch material. Also look at the pressure plate height with one next to the other, they should be fairly close. This will present a problem if they are way off in the operation of the clutch, either not releasing or engaging.

Before re-installing the clutch disc back onto the flywheel fit the disc over the input shaft of the transmission. It should slide onto the shaft with little resistance. This is too help avoid a problem when reinstalling the transmission.
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6. Install the New Clutch: This part is very important! The clutch disc can go onto the pressure plate in either direction but only one direction is correct. The part of the disc that is protruding outward must go toward the pressure plate or the clutch will not release so it's important to install the disc in the proper direction. Also it is important to use brake cleaner to remove grease and dirt from the flywheel and pressure plate clutch contact surfaces before installation.

Gently install the new clutch disc and pressure plate onto the alignment dowels of the newly resurfaced flywheel while installing the mounting bolts by hand. Leave the pressure plate bolts a little lose so the pressure plate can move around. This is so you can insert the clutch alignment tool included in the clutch kit.

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Locate the clutch alignment tool included in the clutch replacement kit. This is needed to line up the clutch disc to the pilot bearing so the transmission can be easily reinstalled.

With the clutch disc loose position and install the clutch alignment tool into the clutch disc and pilot bearing. Slightly tighten the bolts further to hold the disc in place and move the tool in a circular motion. It will give some resistance in all directions and you want to find a good center point. This means the disc is in the middle of the pressure plate.

Tighten the pressure plate evenly and slowly in a star pattern using a ratchet. Do not tighten any one bolt all at once and do not use air tools. This will bend the pressure plate and cause the clutch not to disengage. Work your way around the pressure plate slowly tightening several times until completely tight. You will notice the fingers of the pressure plate traveling inward as you tighten the bolts. You want this progression to be as even as possible. If this step is not done correctly the clutch will not release properly which can cause hard shifting. Finish tightening the bolts to factory torque specifications which is usually between 25 and 30 foot pounds. Again the flywheel will try and turn the engine over so tighten inward.
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Remove the clutch alignment tool and recheck all of the mounting bolts.
 
7. Replace Throughout Bearing: The throwout bearing is designed to push the fingers of the pressure plate inward to disengage the clutch. When these fingers are out or with no pressure on them the clutch is engaged. When replacing the clutch assembly it is highly advised to replace the throwout bearing because it has a high failure rate. Some throwout bearings are attached to the clutch slave cylinder which should be replaced as a unit.

8. Clutch Break-in and Adjustment: Once the transmission has been reinstalled slowly pump the clutch pedal until normal pedal operation is present. Watch and add clutch fluid (brake fluid) in the process. After the repair start the engine and push the clutch pedal down completely while shifting the transmission through its gears. It's normal for this operation to be a little rough while the clutch is in it's "break in" period. Normal shifting characteristics should return after a few miles.

How to replace the rear wheel bearing?

Wheel bearing failure can be catastrophic so it is important to change them when you first start experiencing problems. Typical symptoms include, but are not limited to, the following:

Rumbling sensation when braking or driving along.
Excessive noise from the wheels when braking.
Poor handling when braking.
Knocking or rumbling when cornering.
To check your wheel bearings, jack up the rear of the car and grasp the wheel at the top and bottom. Rock the wheel back and forth and look for play in the bearings. Spin the wheel as well. If it sounds rough, then the bearings are probably on their way out.

In this guide, we are going to replace the wheel bearing and hub assembly. The rear hub assembly is available from smart at a cost of around £70.

To replace the assembly, ensure that you are parked on level ground. Chock the front wheels, slacken the wheel bolts, jack up the rear of the car and remove the wheel.

Support the rear of the car on axle stands. Use the subframe and not the De Dion tube as we need this free to move.

Unfortunately the bolts that secure the rear hub assembly are obstructed by the driveshaft. Therefore, the driveshaft needs to come out. To do this, remove the bolts holding the lower arms of the tie bar.

Use an E16 socket on the bolt. Hold the nut on the rear with a 18mm ring spanner (if you have a mk4 or earlier, you won't have to hold the nut as it is welded to the axle). Support the De Dion tube beneath the rear brake drum with the jack to prevent the bolt from binding. There will be a small amount of tension released as the bolt comes out.

Carefully lower the De Dion tube on the jack. Check the axle stands haven't moved. Now repeat for the other side. Both tie arms need to be free.

Use a 13/16 AF imperial socket to remove the long driveshaft bolt as shown. You will need a long bar to do this as it is held tight.

Undo the bolt on the front of the brake drum with a TX30 bit. Release the handbrake before you try and remove the drum!

Pull the driveshaft out of the back of the hub. You may need to pull the De Dion tube towards you to make enough space. Make sure the car is supported well before you do this.

You can now access the four E14 bolts on the back of the hub.

Remove all four bolts, hold the backing plate for the rear brake and carefully pull the hub free from the car.

The hub has a lip on the back which stops it falling off as you remove the bolts.

As the hub becomes free, we used one of the bolts we removed to hold the brake backing plate to the axle. In this way, you avoid putting stress on the brake lines.

You can now replace your old hub with the new one.

the hub doesn't have a particular 'way up'. Just ensure you don't trap any dirt as you bolt the new hub through the axle and rear brake base plate.

Reassembly is the reverse of removal.

Torque settings:

E14 hub mounting bolts: 65Nm.
TX30 brake disk securing bolt: 6.5Nm.
13/16 AF Driveshaft Bolt: 30Nm + 90°.
Wheel bolts: 110Nm.