It’s all about leverage

Square-tapered BBs that became popular in the early 2000s can be a challenge to overhaul.

Nothing is more frustrating during bike maintenance than a stuck bolt.

Recently I came up against a frozen bolt in my square-tapered bottom bracket (BB), vintage 2000. It’s a sealed cartridge on a Trek mountain bike.

The square-tapered bottom bracket on my mountain bike is not what we all knew and loved in the 1960-80s. It has a sealed cartridge and internal cups. It doesn’t have a lock ring on the left side.

I’ve looked on YouTube quite a bit and this BB has more than its share of issues, especially when it comes to removing stuck bolts.

Before launching into ways to loosen stuck bolts, I recommend you transition to the Shimano Hollowtech II BB. It’s a technical marvel — stronger than other BB designs, larger ball bearings, and way easier to maintain.

I struggled to remove the anchor bolts located on the ends of the BB axle. They hadn’t been removed for 15 years, so they were on there good. I’m sure bolts are torqued down tight at the factory.

It’s not just BB bolts. A while ago I tried removing the chainwheel bolts on my Shimano Ultegra crankset and stripped out two before finally removing them using a hammer drill.

My recommendations for removing stuck bolts, from mild to severe methods:

1. Oil/lubricant. Penetrating oils, even WD40, can help loosen a bolt. My experience is that it doesn’t work, but it’s worth a try.

2. Heat gun. I’ve had occasional success applying heat.

3. Brute force impact. Banging on bolts seems to work best. There are several approaches. First is to use a hammer and chisel and bang away. More sophisticated — use an impact driver, manual or drill. A manually operated reversible impact driver costs about $15. It works like a screwdriver, but instead of twisting with your hand, you bang on the end with a hammer.

An impact driver drill works the same way, but it’s automated. The drill does all the work. It can generate a lot of torque, but it’s not always enough. I had success with one bolt on my Trek BB, but needed to do something different for the other one.

4. Leverage. You may have heard of a “cheater bar.” It’s just a metal pipe that slips over a ratchet. When using this method, it’s imperative to have a well-seated hex head, screwdriver, etc. Add some grinding paste to the end of the screw head to assure a good grip.

I have a really long cheater bar. It came in handy when I removed the crank arms. A long bar offers so much leverage that it’s guaranteed to work — or shear off the bolt.

Once I got the bolts off, I had a Sugino bottom bracket puller (ancient) that worked for extracting the arms. Be sure that it’s seated tightly against the crank arm. I used a large crescent wrench and cheater bar to remove the crank arms. You could also use two crescent wrenches in tandem — one inserted into the face of the puller and one on the threaded bolt that is turned against the axle.

The final step for removing this BB requires a special tool. I purchased the Park BBT-32 20-spline. It’s fine for occasional use. There’s a better one for shop use (BBT-22C), but costs more.

BBT-32 tool from Park is needed to remove the BB cups.

I had no issues removing the threaded cups. Note that the left side cup may be plastic. Use extreme caution removing and replacing to avoid cross-threading. Another plastic component is small dust caps that cover the bolt bolt threads on each side. Pry them off with a screwdriver. They’re flimsy, so don’t be surprised if they break. Metal threaded caps are sold.

Both sides have to be removed. The right, drive side, is steel and in my case with a sealed cartridge is part of the BB.

The left side of the BB may have a white plastic cap that helps keep out debris. It comes right out. There’s another thin threaded bolt on the axle, but it’s not meant to be removed unless you’re trying to maintain the bearings. Don’t bother.

If you want to learn more, check out the First Components website. They have an excellent tutorial with photos.