Originally Posted by
Kuakeye
1. Headset is loose and wobbles slightly. I can probably try taking this apart, clean out the bearings, and tighten everything. However, is it worth it to replace the bearings inside? Where would I even find new bearings?
If you're going to the bother of opening it up and cleaning it out, you may as well do it right and replace the bearings while you're in there. The most common sizes for headsets are 5/32" and 3/16" If you know the make and model of your headset, you can probably look it up, or ask someone here; otherwise take a ball to the bike shop and they can measure it for you and sell you the proper size. Some bearings come in retainers; you can replace the whole retainer/ball assembly if you like, or use loose balls. Loose balls may allow more balls in the race, which spreads the wear over more balls, but are a little trickier to assemble.Fill the race until full, then remove one ball. Grease can hold the balls in place while you assemble everything.
2. The back wheel tube keeps popping. It lasted for a full year before violently exploding while (thankfully) stopped at a stop light. The replacement tube violently exploded a week after replacement, leading me to think that I probably replaced it wrong and the tube probably pinched against the tire or something.
Violent tube failures are almost always installation errors: the tube gets stuck under the tire bead and eventually extrudes out and bursts. Sometime a casing failure in the tire itself is responsible, so check for that as well.
3. The back wheel became out of true after a car decided to take a sharp turn as I passed by, T-boning me...didn't hurt me, but the back wheel took a bit of a dent. Took it to a LBS who tried to true it but could not do it completely, so trued it to the best of their ability free of charge! Wheel is now OK, wobbles side to side ~1/2 a centimeter. Could the back tube be popping so frequently due to the wobbling untrue wheel at all? Since this bike is old and will be used as a beater, I really don't want to invest in a brand new wheel...
Untrue wheels don't lead to tube failures. As long as the rim can pass through the frame and brakes, you can ride it, but it's not ideal. Put a new wheel on your Xmas/birthday list.
4. Back wheel brake cables somehow got severed...no idea how this happened but I figure I just need a new set of brake cables. Brake pads still have some life, maybe 40%.
If the pads are more than a few years old, they can be hardened and less effective.
5. LBS said the bottom bracket bearings need to be replaced. Not sure what this entails, how to check for signs of wear. What happens if I just ignored this? Would the bike still be functional?
For a while it will work, maybe even quite a while. Servicing bottom brackets requires a few specialized tools, which ones you need depend on what type of bottom bracket you have. If you have a cartridge-type bottom bracket, these are not generally serviceable, so when they fail you replace the whole cartridge. Cup-and-cone type bottom brackets are serviceable; you remove the lockring and adjustable cup from the non-drive side, slide the spindle and bearings out, and inspect for wear and damage, replace parts as needed. Spindles wear faster than cups, so look for pits in the bearing track of the spindle. If there are none, repack with fresh balls and grease and be happy. If you do find pits on the spindle, check the cups to be certain they're ok (often they will be), and replace the spindle with one having the same measurements. There are often arcane markings on the spindle that can be used to find compatible replacement spindles.