How To Replace A/C Hose (or Line) Assembly?

Do your A/C hoses leak and need replacement? A/C hoses last an average of 8-10 years. But despite the long service life, the consistent use makes it prone to assembly leaks.

Fortunately, with proper tools and knowledge, you can replace your A/C hoses. We will list down a step-by-step procedure that can save you $500 from going to a repair shop.

In this post, you will:

  • identify tools needed for the replacement or repair
  • safety tips and warnings
  • a step-by-step procedure to perform the replacement.

Safety Tip:

Before performing any repairs, make sure you’re using proper Personal Protective Equipment (PPE) such as mask, gloves, and safety glasses. Refrigerant or Freon, a liquid-gas chemical used in the A/C system, can cause frostbite to skin or lung problems when exposed for long periods.

Things you’ll need:


  • Basic Socket and Wrench Set
  • Pressure Manifold Gauge
  • Vacuum Pump
  • Recovery A/C Machine
  • Recovery Tank


  • Recommended Refrigerant
  • Replacement A/C Hoses or O-rings


  • Hard

Step by Step Procedure: Replacing A/C Hose Assembly

When your A/C malfunctions due to a leak, it will only take a few hours before the circulation gets empty. Leaks may exist anywhere between the hoses and their major components. But once your car has been diagnosed with a hose leak, replace or repair your hoses immediately.

Every car part has part numbers specific to the brand and car model.

Part 1of 4: Recovering the Old Refrigerant

Step 1: Gather the right equipment.

Before unbolting the hoses, make sure the system has no refrigerant. To recover the old refrigerant, use a pressure manifold gauge, recovery machine, and recovery tank.

How to Replace A/C Hose or Line Assembly:

Step 2: Clasp the pressure manifold gauge onto the A/C hose ports.

The blue hose from the manifold gauge hooks to the low-side Schraeder valves, and the red hose to the high-side.

How to Replace A/C Hose or Line Assembly

Keep in mind that the high-side hose is thinner than the low-side.

How to Replace A/C Hose or Line Assembly

Step 3: Set up Recovery A/C Machine.

Set up Recovery A/C Machine. Hook the yellow service hose (the one at the middle) onto the Recovery A/C machine.

Connect the machine to a recovery tank. Then, open both the manifold gauge’s valves to allow the gases to flow out of the assembly.

How to Replace A/C Hose or Line Assembly

Turn the recovery machine on to purge the remaining refrigerant in the system and deliver it to the recovery tank.

Step 4: Close the Gauge Valves.

When the gauge reads 29-30 inches in HG on the low-side gauge, then it means the remaining refrigerant has already been purged out. Close the hand valves and remove the hose connections.

Part 2 of 4: Replacing the A/C Hoses

Before purchasing automotive fluids and oils, consult your owner’s manual for manufacturer recommendation.

Step 1: The replacement hoses should be the same size.

Make sure the new hose matches the size and design of the old one. Car components usually have part numbers to ensure you’re getting the specifications for your car model.

Step2: Disconnect the negative battery terminal.

Disconnecting the negative terminal of the battery is a good practice to ensure safety while working. Use an open wrench to loosen the negative battery cable.

How to Replace A/C Hose or Line Assembly

Step3: Uninstalling A/C hoses.

The A/C hoses must be free from obstructions before uninstalling them. In some vehicles, you need to unmount a few components before you can reach the hoses. Once you’ve cleared the obstructions, use a socket wrench to remove the bolt.

How to Replace A/C Hose or Line Assembly

Some hoses are spring types. You need a disconnecting tool to press down the spring located within the fitting. Once the spring inside expands, the hose will come off.

Step4: Recovering the O-ring.

Once you uninstall the A/C line, make sure the O-ring goes with it. If it’s not located on the fitting, then it might be at the other end of the connection. Make sure that you will replace the hose with a new O-ring. It should never be reused.

How to Replace A/C Hose or Line Assembly

Step5: Installing the new hose.

Most hoses you can buy come readily with an O-ring. Other brands require you to buy O-rings separately.

Lubricate the O-ring with the recommended A/C lube oil. This will help prevent abrasion upon installation and will create an oil film to reduce leakage.

Bolt in the new hose. It shouldn’t be too tight or too loose. You can also check your owner’s manual to see the correct torque for your A/C hose.

Part 3 of 4: Vacuuming the A/C System

Step1: Clasp the pressure manifold gauge onto the A/C hose ports.

The blue hose goes to the low side port, and the red hose goes to the high side. Connect the yellow hose to the vacuum pump.

How to Replace A/C Hose or Line Assembly

Step2: Checking for further leaks.

Open the gauge valves for both the high side and low side line assembly. Turn the vacuum on. Wait until the gauge reads 20-30 inches on Mercury.

Once the system reaches such a pressure reading, close the valves and turn off the vacuum pump. Let the gauge sit for 10 minutes. If the pointer doesn’t change in measurement, then it means the circulation is perfectly sealed and has no leaks.

Step3: Turn the vacuum pump on.

Open both the gauge knobs and leave them for 20-45 minutes. This helps evaporate all the moisture in the system.

Part 4 of 4: Recharging the A/C System

Step1: Use refrigerant as per the manufacturer’s recommendation.

Make sure your refrigerant follows the manufacturer’s recommendation. The most commonly used refrigerant is R134a, an ozone-friendly chemical, as advised by EPA.

Step2: Connect the yellow service hose to the refrigerant valve.

The high side and low side valves must still be closed. Press the purge tip aligned with the yellow hose to purge the remaining air.

How to Replace A/C Hose or Line Assembly

Step3: Recharging the A/C.

Start your engine and turn the A/C on to ensure your compressor will suck in the refrigerant. Open the low-side valve only.

Let the system suck in the refrigerant while watching closely at the gauge. Wait until it reads 25-40 psi on the low side and 200-225 psi on the high side. This means your A/C system is completely charged.

Step4: Check A/C temperature.

You can use a car thermometer to check if the A/C temperature has increased. If yes, then you can start disconnecting the gauge hoses. Done!

How to Replace A/C Hose or Line Assembly

To help you further, here’s a helpful video to guide you step-by-step.

How Do I Know if My A/C Hose Is Bad?

Here are the following symptoms of a bad A/C Hose:

  • A/C stops blowing cool air
  • Refrigerant leaks around the hose
  • Visible damages like bends and crinkles on the hose

How Much Does It Cost to Fix an A/C Leak in A Car?

Diagnosis for A/C leaks averages at $100. Meanwhile, labor for A/C line repairs costs $100 to $150. It may also take you $100-$250 on refrigerant and other replacement parts.

However, if you aim to fix your car but don’t have tools, you can rent equipment such as a vacuum pump at a range of $50-$200.

How Do You Drain a Car A/C Hose or Line?

When you hear water splashing under your dashboard, especially when steering, it usually results from the clogged liquid within the A/C line. Here’s how to drain it:

  1. Turn the engine and A/C off.
  2. Locate the drain line of your A/C system. It’s usually connected to the evaporator but situated in the engine compartment.
  3. Remove any obstruction before working on the clogged A/C line.
  4. Use a stiff brush to remove any debris that clogs the drain line. But a better way is attaching a suction pump to pull out the dirt or debris.
  5. Pour water to check if it easily flows through the drain.
  6. Clean the drain line using commercial cleaning agents or distilled vinegar.
  7. Reinstall the removed components. Start the engine and check if the A/C functions properly.

How Do You Remove A/C Hose Assembly?

Remove A/C Hose or Line with Removal Tool

A/C hoses with spring locks need removal tools to disconnect them. Here’s how to use them:

  1. Turn the engine and A/C off.
  2. Recover the remaining refrigerant.
  3. Locate the leaking A/C line that you need to disconnect.
  4. Position the removal tool around the fitting. Slide it towards the fitting until you feel the spring expanding from the inside.
  5. Once you disengage the spring lock, carefully pull the A/C line away from the connection.

Remove A/C Hose or Line without the Tool

The main goal is to have a tool that would press the spring lock inside the hose. You can remove an A/C line with an improvisation.

Materials needed:

Flexible plastic such as Teflon cylinder or bottle caps

Blade Cutter


  1. Get the empty Teflon cylinder and cut it into a crescent-shaped plastic that would fit through the A/C hose. Adjust the size to fit.
  2. Slide in the improvised tool until it presses the spring lock inside the hose.
  3. Once the spring lock disengages, slowly remove the A/C line away from the connection.

How Do You Fix a Leaking A/C Hose?

Make sure that the A/C system is free from moisture before recharging with refrigerant.
  1. Disconnect the negative battery terminal to assure safety.
  2. Make sure you recover the remaining refrigerant in the system.
  3. Unmount components that obstruct the removal of the A/C hose.
  4. Unbolt/disconnect the A/C line. Check the O-ring and the condition of the hose.
  5. If the hose is in good condition, you may opt to change O-rings. Otherwise, completely replace the A/C line.
  6. Lubricate the O-rings with recommended A/C lubrication oil.
  7. Reinstall the hose together with the removed components.
  8. Use a vacuum pump to remove any remaining moisture in the system.
  9. Reconnect the negative battery terminal.
  10. Recharge the A/C system with a new refrigerant.
  11. Check the A/C temperature using a thermometer. See if it works properly.


  • Before working on an A/C system, recognize its components and how it works first.
  • For safety, disconnect your batteries when performing vehicle repairs.
  • There are automotive shops that offer rents on equipment such as vacuum pumps and Recovery A/C machines.
  • You can add UV dye along with the refrigerant. It helps you find leaks easier using UV light.


  • Refrigerants are ozone-friendly but are harmful to the human body. It may cause frostbite or respiratory problems.
  • Avoid placing refrigerants in hot locations. It has tendencies to explode when exposed to high temperatures.
  • The remaining moisture within the A/C lines can cause corrosion to the system.

Final Verdict

Good thing, you have replaced your A/C hoses. Not only it’s challenging to drive in a hot climate, but the leaking refrigerants also damage the environment.

If you have other issues regarding your A/C system, ask your trusted mechanic to get helpful advice!

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