WARNING: Getting rusted freewheels and rusted cables to work as described below could be dangerous to the rider, causing the rider to have a wreck and injuring the rider. Bending metal as described below could be dangerous. Bending weakens the metal, and could cause the metal to break while someone is riding the bicycle, causing the rider to have a wreck and causing injury to the rider.
Do not fix a biycle as described below if someone else is going to ride it because they might be injured and blame you for the injury. If you will be the only one riding the bicycle, then you may have a wreck and be injured if youfix the bicycle using some of the unsafe methods which are described below.
The only reason I am telling about how tofix bicycles by the methods described below is that manypeople use those methods tofix old bicycles, although some of those methods can cause the bicycle to be unsafe to ride.If you buy an old bicycle, you may assume that the bicycle may have beenfixed so that it could be riddenby using some of the unsafe methods described below.
1. Check the wheels to see if they will be usable. Turn the wheels in the frame to see any obvious problems, such as rims bent, excessive looseness in the bearings, broken spokes, and spoke nipples that won't turn, Check the spoke nipples to see if they will turn by trying to loosen them.
If the inside of a spoke nipple has corroded so much that it will not turn when you try to tighten it, it will usually turn if you try to loosenit. The corrosion which was binding the nipple and the spoke together will usually break loose when you try to loosen the nipple. Thenthe nipplewill turn when you try to tighten it. If your spoke wrench is slightly too large for the nipple, you will round the corners of the nipple so that you will never be able to tighten the nipple. Spokes which were corroded so that you had to break the corrosion loose by loosening the nipple could be near the point of breaking and could be dangerous by breaking while someone is riding the bicycle. It would be saferto replacethem with new spokes instead of trying to save them.
Bent rims can be straightened fairly easily without any special tools, even when bent pretty badly in a wreck (see my article on strainghtening bent rims). But, bending metal can weaken it, causing it to break later, causing injury or death to the rider.
Check to see if the frame is bent or broken anywhere. Bent frames and forks can be straightened without any special tools, but bending metal can possible cause it to break later, causing injury or death to the rider.
2. Turn the crank and see if the chainrings (front sprockets) are bent. See if there is excessive looseness in the crank bearings which might indicate broken bearings or broken cup. If you don't feel roughness in the bearings, and if the sprocket doesn't wobble, it may just need to be tightened.
On one-piece cranks, check to see if the crank arms are bent, and if they are, straighten them or replace them. They can be straightened, but bending metal could cause it to break later causing injury to the rider.
3. Check derailleuts to see if they are bent or have broken or have missing parts. If axle mount derailleur, check to see if the dropout on the bicycle frame has been bent making the slot too wide where the rear wheel axle goes into the frame. If bent, the dropout can be straightened if it doesn't break while straightening. Also, bending metal weakens it and could cause it to break later, causing injury to the rider.
4. Check brake levers and shifters to see if they are usable. If you decide to fix the bicycle, check to see if any grease is left in the wheel bearings. If you want to do it really cheap, and not do it the right way, put some motor oil in the bearings without looking at them. If you want to do it the right way, put some grease in the bearings if needed. Adjust wheel bearings so the wheel turns freely with almost no play in the bearings. Don't tighten the bearings too much because they will get a little tighter when you mount the wheel in the frame.
Take tires off, straighten bent rims, tighten spokes, and true the rims. File off any spoke ends that are sticking through the nipples. Check tires for cuts etc. Feel inside tires and remove anything sticking in the tire that might punch a hole in the tube.
5. Do crank bearings the same way you did the wheel bearings. Straighten bent front sprockets and bent teeth on front sprockets. See if crank arms on 3-piece crank will tighten. If cottered arms won't tighten, replace the cotter pin. See if pedals are screwed into the crank arm as tight as they will go. Oil pedal bearings if they won't turn freely.
6. Do head bearings the same way you did the wheel bearings. See if handlebar and stem can be tightened enough so they won't slip.
WARNING: Putting oil in wheel bearings or in freewheel could be dangerous. The reasons are explained below. The oil could get on the rim, causing the brakes to not work, causing the rider to have a wreck. Putting oil in a freewheel that won't turn backwards could fix the freewheel, but it may not be fixed good and could fail at any time, causing the rider to have a wreck.
7. Straighten bent derailleurs. If freewheel won't turn backwards easily, run some oil in the crack on the freewheel, with some rags to catch any oil to prevent the oil from running down a spoke onto the rim. It would be dangerous to the rider if oil gets on the rim. Lay bicycle or wheel on its left side for several minutes or an hour until all the excess oil runs out onto the rags.
If the freewheel bearings are rusted and will not let the freewheel turn backwards at all, put some WD-40 in the freewheel and then work the bearings loose until the freewheel will turn backwards freely and will not turn forward. Just put pressure trying to turnthe freewheel counterclockwise, and then trying to turn it back clockwise. Do this many times until the freewheel will turn counterclockwise freely. Then, put some heavier oil in the freewheel Leave wheel laying on its side long enough so that all excess oil runs out and is caught on a rag.
WARNING: Putting oil in a freewheel as described above could cause the bicycle to fail, causing the rider to have a wreck, and causing injury to the rider. If the freewheel starts working, it may not be catching good and may slip when the rider is pedaling, causing the rider to have a wreck, and causing injury to the rider. Also, if oil gets on the rim, it could cause the brake to not work, causing the rider to have a wreck.
8. WARNING. Fixing rustec cables as described below may be dangerous to the rider, causing the rider to have a wreck and to be injured.
Cheap way to fix rusted brake and shifter cables: If the inner cable wire will not slide in the casing, or will not slide easily, it may be rusted. Run some oil or WD-40 into the cable without taking the wire out. Make some kind of little cup out of paper that you can fasten to the top ot the cable. Put several drops of oil in the cup and hang the cable so that the oil will run down into the cable with the wire in the cable housing until the oil gees out the bottom of the cable. Of course, it is better to take the inner cable wire out of the cable, sand the rust off, and twist the inner cable to see if any of the strands of wire will break where rusted (twist to see if it breaks before sanding. (Do not get any oil in friction shifters or on rim of wheel). If the inner cable will not slid at all, bend the cable everywhere by pulling it over a round object such the handle of a hammer.
WARNING: Rusted cable may break at any time, causing the rider to have a wreck and causing injury to the rider. It would be safer to replace the rusted inner cable than to make it work by sanding it and oiling it.
9. Adjust rear derailleur so that it will not push the chain off the largest cog and get the chain wedged between the largest cog and the spokes. Adjust so that the chain will not gee off the smallest cog on the outside. If index shifter, adjust so that it goes into each gear properly.
Adjust front derailleur so that the chain will not gee off the smallest front sprocket on the inside, and will not be pushed off the largestfront sprocket on the outside.
Put some oil on the pivot points of derailleurs and let the oil run into it. Don't let oil drip onto wheel spokes because it might get on the rim, and that would be dangerous to the rider.
10. Stretch new brake cables by pulling the brake lever fairly hard several times, then readjust brakes. Check to see if brakes squeal, and if they do, toe in the shoes so that the front part of the shoehits the rim slightly before the rear part of the shoe touches the rim.
11. Measure 24 links of the chain and if it measures 12 1/8 inches or more, it is time to replace the chain. However, it might be best to not replace the chain if the sprockets, front or rear, are worn too much. If you put a new chain on a sprocket that is worn too much, a new chain may ride up a tooth and JUMP over the tooth while the rider is pedalling. This could be dangerous. In this case, the chain AND the front and rear sprockets would need to be replaced, but this might be too expensive on a cheap bicycle.
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