The E30 Fuel Line Fix: A Comprehensive Guide

Replacing the fuel lines on an E30 can be a challenging task, but it is doable for those with some automotive repair experience. The process involves working with both metal and rubber fuel lines, and it is important to use genuine BMW parts and new jubilee clips to ensure safety and prevent leaks. The hardest part of the process is often getting the rusty screws undone on the clips, which can break or snap. It is recommended to have the car on axle stands or ramps to access the fuel lines more easily. Additionally, it is advised to check the state of all rubber lines annually and replace them as soon as they show signs of aging.

Use a flathead screwdriver or socket wrench to tighten fuel hose clamps

When tightening fuel hose clamps, it is important to strike a balance between ensuring the clamps are tight enough to prevent leaks, and not over-tightening, which can damage the hose.

A flathead screwdriver or socket wrench can be used to tighten fuel hose clamps. Flathead screwdrivers are simple and widely available, making them a common choice for basic worm gear clamps. They are suitable for older or simpler hose clamps with slotted screw heads. However, they can be prone to slipping, especially if the clamp is tight or the screwdriver blade is not a perfect fit.

Socket wrenches, on the other hand, can apply more torque than screwdrivers, making them ideal for tightening hose clamps that require a stronger and more even clamping force. They are particularly useful for T-bolt clamps and heavy-duty worm gear clamps. Socket wrenches are available in various sizes, allowing you to select the perfect fit for the clamp's screw head.

When using a flathead screwdriver or a socket wrench to tighten fuel hose clamps, follow these steps:

• Select the correct tool: Choose a screwdriver or socket that fits the clamp's screw head perfectly.
• Position the screwdriver or socket: Insert the screwdriver into the screw head or attach the socket to the wrench and fit it over the clamp's bolt or nut.
• Tighten the clamp: Turn the screwdriver or wrench clockwise to tighten the clamp. Apply steady pressure and turn the screw evenly. Tighten until the clamp feels snug but not overly tight. Ensure that the clamp is evenly applied and that the hose is securely attached to the fitting.
• Check the seal: Inspect the clamp to ensure it is evenly applied and that the hose is securely attached. Check for any signs of leakage.

It is important to note that over-tightening hose clamps can lead to several problems, including hose damage and reduced clamp effectiveness. Conversely, under-tightening can result in leaks and clamp slippage. Therefore, it is crucial to achieve the right amount of tension when tightening fuel hose clamps.

Use needle-nose pliers to remove old clamps

To remove the old clamps, you'll need a pair of needle-nose pliers. This is a delicate task, so be sure to take your time and apply gentle but firm pressure as needed.

First, locate the hose clamp on the middle hose. Loosen it enough so that you can push it up and away from the hard line. Depending on the condition of your hoses, you may encounter a crimped band clamp. If this is the case, use your needle-nose pliers to carefully twist and pop the clamp open. You might want to have a rag handy, as some fuel could leak out at this point.

Once the clamp is loose, carefully grip the fuel hose with the pliers and firmly pull it off the hard line. If the hose is original, it may be stuck firmly in place. In this case, carefully slice along the length of the hose with a razor blade to free it. As soon as the hose is removed, fuel will begin to drain out, so have your drain pan ready.

Now, move on to the charcoal canister. The canister is located underneath the brake fluid reservoir and power steering pump reservoir. Stand in front of the driver-side mirror and look down and forward into the engine bay to spot it. Remove the hose clamp from the bottom end of the hose using your needle-nose pliers. Again, if the hose is stuck, carefully slice through it with a razor blade, being very careful not to damage the new supply and return lines.

Finally, twist and pop the crimped band clamp open with your needle-nose pliers to release the hose from the nipple on the canister. Pull the hose out of the car, and you're done with this step.

Jack up the car to access the hoses more easily

Jacking up your car is a necessary step in replacing your E30's fuel lines. Here is a detailed, step-by-step guide on how to do it safely and effectively:

Firstly, find a safe place to pull over and work on your car. Get off the road and move as far away from traffic as possible. Ideally, you want to be on solid, level ground, such as a parking lot. If you can't find a parking lot, look for a road or street with minimal traffic and pull over to the side, ensuring you're on a solid surface that can support a jack.

Next, secure your vehicle. Make sure the engine is off, the car is in park, and the parking brake is engaged. For added safety, block the tire opposite to the corner you'll be jacking up. For example, if you're jacking up the right front, block the left rear tire. This will provide extra insurance against the car rolling off the jack.

Now, locate your car jack and jacking points. The jack is typically stored in the trunk or, for SUVs, under the cargo-floor cover. Jacking points are reinforced metal ribs specifically designed to lift the vehicle safely. There are usually four jacking points on most vehicles: under the car's rocker panels, just behind the front wheels, and just ahead of the rear wheels. Check your owner's manual for the exact locations on your E30.

Once you've located the jack and jacking points, position the jack under the jacking point. Most car jacks have a slot at the top that slips onto the jack point's reinforced rib. However, your car may differ, so refer to your owner's manual for specific instructions.

Now, it's time to jack up the car. Turn the jack handle clockwise slowly until the desired tire is off the ground. Take your time and ensure that the jack remains straight up and down as it lifts the car. Do not let the jack lean, as it won't hold the car securely.

If you plan to work under the car, it's crucial to use a jack stand for added safety. Place the jack stand under the rocker panel near the jack and snug it up against the car's body. This will ensure the car doesn't fall on you if the jack slips or fails.

With the car securely jacked up, you can now easily access the fuel hoses for replacement. Remember to always exercise caution when working on your vehicle, and refer to your E30's manual for any model-specific considerations.

Remove old fuel lines and replace with new lines

To remove the old fuel lines and replace them with new ones, begin by checking the fuel level. The closer your gas tank is to empty, the easier this job will be. If you can time this job between fill-ups, there will be less fuel to deal with when you disconnect the lines.

Jack up the front of the car and set it on jack stands. This will make it easier to get to the hoses.

Next, locate the lower connections for the three hoses you will be replacing. Their connections to the hard lines are on the inside of the driver-side frame rail, just in front of the firewall. The lower two hoses are the supply and return lines, and the line above them runs to the charcoal canister.

Now, start at the top connections. Unroll your length of new fuel hose and run a line from the top connections down to the bottom, following the path of the existing lines.

Move back to the bottom connections and start with the supply line. When you disconnect the line, fuel will want to leak from the gas left in the fuel rail and the fuel tank. This is why you ran a hose down from the top of the engine bay earlier; you want it ready to connect to the hard line immediately.

Slide a hose clamp onto the end of the new fuel line, about 2" up from the end, and tighten it just enough to keep it from sliding down the line.

At the bottom connections, loosen the hose clamp from the middle hose. If your car is older, the clamp may be a crimped band clamp. If so, use a pair of needle-nose pliers to pop the clamp free. You may start to leak some fuel at this point, so have a rag ready and slide the drain pan underneath. Loosen the clamp enough that you can push it up the hose to clear the hard line.

Grab the fuel hose and firmly pull it off the hard line. If it's original, it might be really stuck, in which case you can carefully slice it along its length to free it. As soon as the line comes off, push the end of the new fuel hose onto the hard line until it butts up against the ring on the line. Let the hose drain into the pan.

Loosen the hose clamp on the new line and slide it down into place. You want a small space between the end of the hose and the clamp, but you want the clamp fully over the hard line. Tighten it.

Move to the top connections and pull any extra slack out of the new fuel line so that it follows the path of the existing fuel lines. Line the new hose up with where the old line is still connected to the fuel rail, then use a razor blade to cut the hose to the correct length.

Place a new hose clamp over the end of the new hose. Loosen the hose clamp on the old hose (the lower one) and pull the clamp back to clear the hose clamp. Pull the old hose off the fuel rail connection. If it's really stuck, you can slice it with a razor blade. Quickly slide the end of the new hose over the connection to avoid spilling more fuel.

Slide the hose clamp over the connection and tighten it. As with the bottom, you want the clamp fully over the hard line connection, but with a little space before the end of the hose.

Now, run the return line by repeating the above steps.

Finally, replace the line to the charcoal canister. From underneath the car, remove the hose clamp from the bottom end of the hose and pull the hose off the hard line. Cut it with a razor blade if it's really stuck, just be careful not to nick the new supply and return lines.

Move above the car. The charcoal canister is located underneath the brake fluid reservoir and power steering pump reservoir. If the hose is original, it will be secured with a crimped band clamp. Remove it using a pair of needle-nose pliers to twist it and pop the clamp open.

Pull the hose off the nipple on the canister and pull the hose out of the car. Lay the old hose out along your new hose and cut a piece to the same length.

Slide a hose clamp over the end of the hose, about 2", and snug it up just enough to keep it from falling off the hose. Slide the end of the hose over the nipple on the canister and push it on until it runs into the bend in the hard line. Loosen the hose clamp, slide it near to the end of the hose (so that it's definitely behind the nipple), and tighten it.

Move back under the car. Slide a hose clamp over the end of the hose and push the hose onto the end of the hard line. Slide the hose clamp over the nipple near the end of the hose and tighten it.

Add zip ties to make sure the lines stay where you want them. You can place one around the supply and return lines, and the pipe for the oil dipstick. Snug it up just enough to keep the line in place, you don’t want it to actually compress the hoses.

Start the car and inspect all of the hose ends for leaking. Let the car run for a couple of minutes. If you see any leaks, turn the car off and tighten up the hose clamps. Wipe off any leaked fuel, start the car, and re-inspect.

Once you have confirmed that there are no leaks, jack the car back up, remove the jack stands, and lower the car.

Check for leaks and tighten hose clamps if necessary

Once you've replaced the fuel lines, it's important to check for leaks and tighten the hose clamps if necessary. This is a crucial step to prevent fuel leaks, which can be dangerous and cause fires.

Start the car and let it run for a couple of minutes, then inspect all the hose ends for any signs of leaking. If you notice any leaks, turn off the car immediately and tighten the hose clamps. Wipe off any leaked fuel, then start the car again and re-inspect for leaks.

It is recommended to only tighten the hose clamps enough to keep them from sliding down the line. Over-tightening can pinch the hose. A screwdriver with a socket end is a good way to feel how tight is tight enough.

If you notice leaks around the hose clamps, it may be necessary to replace them. Crimped band clamps, in particular, may need to be replaced with new hose clamps if they are not holding the hoses securely.

Frequently asked questions