Replacing The Fuel Accumulator In Your Mercedes 450Sl: Diy Guide

The fuel accumulator in a Mercedes-Benz 450SL is located behind the right rear wheel, mounted with the fuel pump and filter. It is an essential component of the K-JETRONIC fuel injection system, preventing hot start vapor lock and maintaining pressure and flow in the fuel distributor. When the fuel accumulator is defective, the car may experience starting and running problems. Replacing the fuel accumulator involves working with the fuel system, so there is a potential fire hazard. It is important to take safety precautions, such as disconnecting the battery's negative cable, working in a well-ventilated area, and having a fire extinguisher nearby. The replacement process involves removing the existing fuel accumulator and installing a new one, ensuring proper clamping and connections.

The fuel accumulator is located behind the right rear wheel

The fuel accumulator on a 1979 450SL Mercedes-Benz is located behind the right rear wheel. It is mounted in a cluster with the fuel pump and filter. To replace the fuel accumulator, you will need to remove the whole cluster and place it on a workbench or another flat surface. This is because the biggest issue when replacing the fuel accumulator is the potential for a fuel spill. You may also need to change old rubber fuel lines and the filter.

When removing the cluster, it is recommended to use fuel line clamps and a large catch bucket to avoid a fuel spill. Even with these precautions, a fuel spill may still occur, so be prepared for this eventuality.

Overall, replacing the fuel accumulator on a 1979 450SL Mercedes-Benz is considered an easy job that can be done by a skilled individual.

It's an easy job, but be prepared for a fuel spill

Changing the fuel accumulator on a Mercedes 450SL is an easy job, but it's important to be prepared for a potential fuel spill. The accumulator is located behind the right rear wheel, mounted with the fuel pump and filter. Before beginning any work, it's crucial to take safety precautions when working with fuel systems. Disconnect the battery's negative cable to minimise the possibility of sparks, and work in a well-ventilated area away from any open flames. Ensure the car is cooled down before starting, as fully heated catalytic converters can ignite fuel vapours. Always keep a Class B fire extinguisher within reach.

When working on the fuel system, it's advisable to capture the gas in an appropriate container and relieve pressure from the system before removing the existing fuel pump. This can be done by pinching off the suction hose with special U-style clamps or DIY alternatives like small C-clamps or locking pliers. Protect the fuel line from the pliers' jaws to avoid damage.

Removing the whole cluster of the fuel accumulator, pump, and filter is the easiest approach. Place the setup on a workbench or any suitable surface to continue the job. Be cautious, as the biggest challenge is the potential for a fuel spill. Old rubber fuel lines may need to be changed, and it's recommended to change the filter as well. Using fuel line clamps can help manage the fuel, but even with these precautions, some gasoline spillage is likely.

Overall, while changing the fuel accumulator on a Mercedes 450SL is a straightforward task, taking the necessary safety measures and being prepared for potential fuel spills are key to a successful and safe experience.

You'll need fuel line clamps and a large catch bucket

When changing the fuel accumulator on a Mercedes 450SL, it is important to be prepared for a potential fuel spill. To minimise the risk, you will need fuel line clamps and a large catch bucket.

Fuel line clamps are essential to prevent fuel leaks. There are various types of clamps available, including U-style clamps, spring-type clamps, and worm-gear clamps. The OEM sliding-style hose clamps are typically one-use only, so you will need replacements. Spring-type clamps are user-friendly and often included with a new fuel pump. Worm-gear clamps are another option, but they must be tightened correctly.

A large catch bucket is necessary to capture any spilled fuel. Even with proper clamping, some fuel may escape, as one user reported: "I used fuel line clamps when I switched mine. And a large catch bucket below everything. But I still got gasoline on the floor and all over my forearms."

Therefore, it is crucial to have the necessary tools and safety equipment when changing the fuel accumulator on a Mercedes 450SL.

The accumulator is checked by removing and plugging the small hose

The fuel accumulator in a Mercedes 450SL is located at the rear of the car, next to the fuel pump and filter. It is part of the K-JETRONIC fuel injection system and helps to prevent hot start vapor lock and maintain pressure and flow in the fuel distributor.

The accumulator can be checked by removing and plugging the small hose connected to it. To do this, first locate the accumulator behind the right rear wheel. Place a catch bucket underneath to catch any spilling fuel. Then, remove the small hose from the accumulator and plug it.

Now, start the car. If the accumulator is functioning correctly, there should be no fuel leaking from the hose fitting. You may get an initial squirt of fuel on start-up, but it should not continue leaking. If the hose continues to leak fuel, the accumulator is faulty and needs to be replaced.

When replacing the accumulator, it is recommended to also change the fuel filter and any old rubber fuel lines that may be present, as these can also cause fuel leaks. Additionally, a fuel pressure test should be performed to ensure there are no issues with fuel pressure, which can also cause starting problems.

A bad fuel pump check valve can also cause problems

The fuel accumulator in a Mercedes-Benz 450SL is located behind the right rear wheel, mounted with the fuel pump and filter. It is an essential component of the fuel system, assisting in preventing hot start vapor lock and keeping the pressure and flow in the fuel distributor consistent.

Now, a bad fuel pump check valve can cause several issues with the vehicle's performance. The check valve in the fuel pump is responsible for maintaining the proper amount of pressure in the fuel system. When this valve goes bad, it can cause the following problems:

• Poor engine performance or stalling: A faulty check valve will not be able to maintain the correct fuel pressure, leading to the engine running poorly or stalling.
• Inability to start: The vehicle may not start at all due to a lack of pressure, which allows fuel to flow back into the pump.
• Difficulty starting when cold: A bad check valve can cause all the fuel in the fuel rail to drain back into the tank overnight, making it challenging to start the engine in the morning. The engine may require multiple attempts to start or crank for an extended period before firing up.
• Engine sputtering at high speeds: This can be an indication that the fuel pump isn't delivering enough volume due to a faulty check valve.
• Loss of power during acceleration: Low fuel pressure or volume caused by a bad check valve can result in a loss of power when accelerating or driving uphill.

To diagnose a bad fuel pump check valve, you can perform a simple test. Let the vehicle sit overnight, then turn the key to the "RUN" position a few times without starting the engine. Repeat this process a few times, and then try to start the engine. If it starts right up, it's likely that the check valve is faulty and needs to be replaced.

It's important to note that, in some vehicles, the check valve is built into the fuel pump and cannot be replaced separately. In such cases, you may need to replace the entire fuel pump to address the issue.

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