Hello,

I want to learn how to work on my own bike. I am 48 years old and never tore into bearings or technical stuff. so I am going to learn on my old Centurion bike I bought for $50 and dropped a few bucks into it to get it running the chain was all rusted and everything. I rode it 30 miles round trip to work last summer. I really like it. I use it as my going to the store bike and don't worry about it getting it stolen. it is a 70's bike. So here is a picture of my lower bracket what type is it? I went to Park tool but they had a lot of types to choose from. so I am looking at a starting point thanks.

Square taper cup and cone "bottom bracket" (BB for short) with alloy (aluminum) crank arm attached.

You will be way ahead if the first thing you do is to Google bicycle part diagram and study mulitple versions of what you find. Then do the same for individual parts, like the bottom bracket. To start working on them go back to Google and add repair, replace, adjust to the part name. For the two most popular and respected sites add Parktool or sheldon. Don't limit yourself to one section of one page about one part. Many parts on a bike are either directly or indirectly affected by others. No tool or knowledge is more important than your mind. You need to think at every point about the why of what you are doing. Don't forge ahead on "instinct" or think that trial and error teaches effectively.

In your particular case that BB is looking very neglected, but rust may provide some challenges in disassembly. Try penetraing oil, PB Blaster or similar to assist if you really want to tackle it. But keep this in mind - you may need quite a few tools and time to accomplish the entire task of BB overhaul, and you will if ever rarely have to do that task again. If compatible cup and cone parts are not available or too expensive and you install a cartridge BB it will require an additional tool, and will make some of the others you purchase obsolete for that bike.

As your goal is learning how to work on your own bike, in my view you may be better off having the overhaul done professionally. Then use your time to address the other repairs that are important (brakes, tires/wheels, shift system) and use your funds to buy the tools you will actually need on a regular basis.

If you still just want to do it yourself this is my recommendation:

Given the BB condition don't even bother trying to save it. Use the proper tool to pull the crank arms, remove the lockring with a hammer and punch (CCwise) then use a pipe or channel-lock wrench to grab and take off the cup. Use Sheldon's homemade tool for the fixed cup or have a shop remove it. Finally, get a compatible cartridge unit and install it. Net cost: crank extractor, cartridge tool and cartridge BB, plus whatever cost is of getting fixed cup off. Takes much less time and avoids the purchase of tools you may not need in the future.

Here's a link to the one I bought: https://www.nashbar.com/bikes/Product...41_-1___202576

You'll also need a crank puller: https://www.nashbar.com/bikes/Product...06_-1___202576

Don't try to remove a crank without a puller. It can be done, but it's not worth doing.

He needs a pin wrench or similar to remove the adjustable cup, doesn't he? What works with that style cup?

Use a cheap flat screw driver & hammer to remove the adjustable cup. Without actually opening the bottom bracket it's impossible to tell what condition it's in. Many that are ugly on the outside are just fine.

Thank you all for the help