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FCP Euro Service Kits

FCP Euro Kits

Many a DIY'er has been there before - you've just completed several hours of hard labor replacing several key suspension components and all you have to do is get the wheels on before you can drive off in to the sunset when disaster strikes! What type of disaster? None other than a stripped thread - in this case, on the wheel hub, but stripped threads can strike just about anywhere, anytime.

Stripped threads can be caused by several things, such as cross threading or over-torquing, but whatever the reason it can stop a project in its tracks as you cannot install that last important fitting. Unlike a stuck bolt no amount of heat, oil, or brute force is going to get it to work!

Thankfully some ingenious person came up with the idea for something called a "helicoil" repair. In short, you drill out the old threads, use a tap to create new threads that the helicoil itself then threads into, and then said helicoil matches the size and pitch of the old threads. Once installed your bolt can be tightened, as good as new!

Before starting this type of job, you'll need to identify the thread size and pitch on your existing bolt and purchase a helicoil repair kit that matches. The kit should include the proper size drill bit, a tap that will create threads for the helicoil, a set of several helicoils, and an installer tool. Pictured below are the tap, and one of the helicoils, that came with this particular kit.

Read on to get the step-by-step process for the day when, not if, you find yourself dealing with a stripped thread!

Step 1

Identify the problem threads - in this case, one of the five lug holes in this rear hub on a 1984 Mercedes 300D became stripped. You can see the metal shavings from the lug bolts that were damaged by the stripped threads while attempting to torque the wheel after replacing some driveshaft and axle components on this 300D.

Step 2

Begin drilling the old threads out using the supplied drill bit. Be extremely careful to keep the drill as true, straight, and level as you can! If you drill the threads out crooked the bolt will not going in straight after the helicoil is installed.

Step 3

Once you've drilled out the old threads, use the tap to create new threads in the hole. Try and do this by hand - using power tools for this can lead to the tap breaking which is VERY bad. The tap is hardened metal that cannot be drilled out readily.

Here is a picture of the threads that the tap created in the hub.

Step 4

Now, use the helicoil installer as described in the kit instructions to install the helicoil in to the hole.

Step 5

The installer in this kit threaded the helicoil in just until it reached the back of the hole in the hub and then it stopped. This left excess coil sticking out. Wire cutters served fine to cut off the excess.

With the excess removed, you can see the brand new threads made by the helicoil inside the hub hole. These threads are a precision match for the threads on the lug bolt.

Step 6

With the helicoil repair kit installed, you can put the wheel back on and hit the road!

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Written by :
Nicolas Siemsen

Nicolas lives in Tucson, AZ where he spends his weekdays as an emergency manager, and his weekends working on cars, either his or his friend's. He has a passion for old cars, which he indulges through the classic W123 Mercedes-Benz, and for fast cars, currently an E39 540i M-sport.


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