Below is a video on how re-drill your 4 lug Subaru hubs to make them 6 lug.
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Today we will be showing you how to re-drill your older 4 lug by 140 Subaru hubs. We are re-drilling them to add four more wheel stud to make it a 6 lug by 5.5. The most common reason people to this is because it’s hard to find larger aftermarket rims for the 4×140 lug pattern as most 4 lug cars were 4×100. We are doing it so we can upgrade to a 15” rim so we can run a 30×10.5 tire on this lifted Subaru. The 6 lug 5.5 wheels are commonly found on Toyota, Chevy, Nissan, Mitsubishi.
To start remove the hubs from the car. Once removed you will want to spray each wheel stud you plan on removing with kroil penetrating oil. I sprayed mine the night before so the oil can soak in. We are removing the wheel studs that are straight across from each other. Next we will need a lug nut or two. Next thread the lug nut or nuts onto the wheel studs that you are removing. Once threaded all the way on you can use a bench vise and hang it off the edge and hit the lug nut with a hammer pushing the stud out of the hub. If you don’t have a vise you can use two hardwood blocks and set them on a hard level surface and then place the hub on the wood making sure that the wood is near the stud you want to remove but not directly under it so it can be hammered out.
Once you have finished removing the studs from that hub repeat the process for the other front and rear hubs. Now that we have two wheel studs removed from each hub (straight across from each other) we can grab our 6 lug rim that we are using for a template. Once you have the template rim we can stand it on edge. With the rim on edge we can take a hub and slide it into the rim and put two lug nuts onto the wheel studs that are left and snug them down with a 1/2-Inch ratchet and a 19mm socket. Making sure to go a little bit on each one back and forth until there both tight to ensure that the hub centers itself in the rim.
With the lug nuts tight we can lay the rim flat on a level surface with the lug nuts facing up. Next we can grab a 9/16 center/ transfer punch and a hammer. Take the 9/16 center punch and slide it into a wheel stud hole hold it straight up and down and then give it a few taps with the hammer. What the center punch is going to do is make a mark on the hub in the center of the wheel stud hole so you have a dimple to start drilling to prevent the drill bit from walking. Repeat the process for the rest of the wheel stud holes so that each wheel stub hole has the dimple. With all the wheel studs marked out I will take a permanent marker and just mark around the dimple making it easier to see. With all the wheel studs dimpled and marked out you can repeat the process for the other hubs.
With all the hubs dimpled and marked the next step is to drill the hubs. It’s best to use a drill press. If you don’t have a drill press you can use a corded or cordless drill just be sure to drill straight. If you don’t your wheel studs will come out on whatever angle you drilled them on making it hard to bolt your wheel on. Next mount the hub in the drill press. We will first start by using a 1/4drill bt and drilling all four holes that size. It helps to go at a slower speed and to use cutting fluid/ oil. Once we have finished drilling the four holes with the ¼ drill bit we can replace the bit with a 3/8 drill bit and drill the four holes to that size. Once we have finished drilling the four holes to 3/8’s we can replace that bit with a 9/16 drill bit and drill the four holes to that size. Once we have finished drilling that hub and all the holes are drilled to 9/16’s we can repeat the process to the other hubs.
With all the hubs drilled if you take your new wheel studs and try to put them into the front hubs you will notice they won’t lay flat in the hub as there is a tab/ metal in the way. Next we can take an angle grinder and grind away some of that metal so the new wheel studs can lay flat. I will also take a lug nut and tighten it into the vise and then thread a wheel stud into it so I can grind a little bit off the inside or flat part of the wheel stud so it will better fit against the hub.
With the two front hubs ground down so the wheel studs can sit flat we can mount the hub in the wheel again and tighten the studs down by hand. Once tightened down by hand we can take a ratchet and a 19mm socket and tighten them making sure to go a little bit on each one back and forth until there both tight to ensure that the hub centers itself in the rim.
With the two original wheel studs tightened down we can insert the new wheel studs and lug nuts. Once we have all the new wheel studs in and lug nuts on them we can run them down hand tight. Once hand tight we can take a ratchet and 19mm socket and tighten them down in a crisscross pattern until tight. With all the lug nuts tight it’s a good idea to take your welder and put a tack weld on each of the new wheel studs just to ensure them can move or become loose. Once I have the new wheel studs tacked in we can repeat the process for the rest of the hubs.
With all the new wheel studs tacked in that’s it you have finished re-drilling your older 4×140 Subaru hubs to a more popular 6×5.5 wheel pattern. To finish them off you can sand blast them and give them a fresh coat of paint.
Here’s the hubs mounted back on the car.
1987 Subaru GL Hatchback <— Click to read/ see more of the build of this car.