Threaded Fork Installation

The new fork arrived. The steerer tube (the tube that the handlebar stem fits into) was about 2 cm too long, so that needed to be cut down. Other than that everything could be transferred over. If your original fork was a perfect fit for your bike, you can simply compare the steerer tubes side by side to see if the new fork is the correct size (too big is ok, too small is bad). I decided to install the fork, and then measure it with the headset in place for better accuracy. Here is the link to my previous post about removing the old fork.

First I had to transfer the crown race over from the old fork. I used a 12" long socket wrench extension and a hammer to tap it off the old fork. You could also use a big flat bladed screwdriver or a punch. Gently tap it little by little on each side until it eventually falls off:

 

Now the race needs to be installed on the new fork. I used a 2x4" piece of wood to brace the new fork underneath the steerer tube. Next I slid the race on, then used a 1" diameter PVC pipe and a hammer to drive the race into its seat. If the race isn't seated properly the headset will loosen up later on, so give the pipe a few extra taps to be sure (the sound will change a little once it bottoms out):

 

Next I reinstalled the bearings into the frame cups. The grease should hold them in place:

Now I slid the fork through the frame and screwed on the top race to hold it in place. I added the rest of the headset pieces, and marked where I needed to cut it (about 2 mm below the top of the locknut). I then removed the fork, clamped it in a vice, and used a hacksaw to cut it to size. I also used a grinding wheel and a round file to clean up the threads. Here is the cut fork:

 Now it's time to install the top nut and adjust the headset. The top race should be screwed on finger tight, then the top nut should be tightened down. The top race should be supported while tightening the top nut, either with a headset wrench, or with my stupid vice grip method:

 

After tightening the top nut, make sure the fork spins freely with no play. Headset play is the most annoying thing ever, so I prefer to adjust the bearings with a tiny bit of drag rather than have them loosen up later. If the headset keeps getting loose I'd use a little blue locktite on the fork threads to keep the race in place. Here is the completed headset:

Now you can reinstall everything that was attached to the fork:

I ended up having to change the front brake, so I can show you a quick way to adjust the cable. This brake has a barrel adjuster, some bikes might have the adjuster on the levers or on a bracket in the headset. Unscrew the adjuster most of the way out, then press the pads to the rim. Bolt down the cable while holding the pads, then screw the adjuster back in until the pads are a desirable distance from the rim:

All you have left to do is align the handlebars and check the bolts to be sure they're tight. This really isn't a big job as long as you have the right tools (and the right replacement fork...). You will definitely need a wrench big enough to fit on the locknut, a hammer, a 2x4, a cheap piece of PVC pipe, as well as a saw or cutting disc to cut the new fork (if needed). A damaged fork doesn't need to be the end of a bike after all.

Threaded Fork Removal

I heard a creaking noise while riding my bike today. The bike has decent parts on it and I assembled it all myself, so I really couldn't figure it out until I saw this:

 

 One of the fork blades has a hairline crack in it. Time to get a cromoly one. In the meantime I thought I'd do a little tutorial on how to swap out a damaged fork. In the next post I'll also show you how to adjust the bearings that hold the fork in place. Anyway first you should remove the front wheel. Next remove anything else attached to the fork, like brakes, computers, racks, fenders, whatever. Road caliper brakes are held on by a nut on the back of the fork crown. Cantilever/V-brakes have a bolt on the front side of each brake arm. Disc brake calipers usually have 2 bolts on the side of the fork blade. You also need to remove the handlebar stem:

I didn't have to remove any of the cables, which is nice. Now with everything out it's time to remove the fork. For a threaded fork you do this by unscrewing the headset locknut and top race:

This is most easily done with a big adjustable wrench on the top nut while holding the top race with a headset wrench if it has wrench flats. This bike's top race doesn't have wrench flats, so I use a vice grip with a towel wrapped around the race to hold it in place. The towel protects the finish from the jaws of the vice grip. With both of these removed, the fork can slide out:

 

Keep track of any spacers, reflector brackets, or cantilever brake cable stops that might also be sandwiched between the two nuts on top. Once the fork is out you should pull the ball bearings out of the headset cups, and clean the bearing surfaces:

I'll show you how to install a new fork in my next post. I bought this one used. Never again.

One Piece Bottom Bracket Overhaul

Most old American made bikes have one piece cranks. These cranks are a solid steel bar with two 90 degree (ish) bends which the pedals attach to. They're primitive, heavy, and fantastically durable. This procedure will show you how to overhaul these bearings. No special bike specific tools are needed, but you will need a big wrench that can fit a 1-1/4" large nut. If you don't have the wrench and your cranks don't have any play in them then dripping motor oil into each cup can get you by, but whats the fun in that? The bike shown here is a Schwinn Continental.

First remove the left side pedal. I often have good luck using a thin adjustable wrench. Remember it's reverse threaded:

Now remove the large nut on the left hand side. This is also reverse threaded:

Remove the keyed washer, then use a screwdriver to unscrew the cone (reverse threaded):

The next step is a little tricky. You have to slide the crank out through the bottom bracket shell. You'll need to remove the bearings from the frame cups first before the cranks can come out:

Now clean and grease the bearing surfaces:

Reassembly is the opposite of removal:

Once the crank is back in place, rethread the cone back onto the left side. Leave some play in the bearings for now:

Now replace the keyed washer, then the lock nut:

Here comes the trickiest part. You need to dial in the bearing's adjustment. There must not be any play, but the cranks should spin freely too. For some bikes, tightening the lock nut will dramatically increase the preload on the bearing, so be sure to spin the cranks after tightening. Make adjustments by loosening the nut, then turning the cone until you get the desired setting:

Again, there definitely should not be any play here once the lock nut is tightened, since the bearing cups are merely a press fit into the frame. Finally, retighten the left pedal and you're set.

Schwinn Rear Derailleur Overhaul

Schwinn's popular Varsity and Continental models featured the Huret Allvit rear derailleur. It's not a particularly durable or precise derailleur, and they commonly won't shift well after years of neglect. Never fear, I'll show you how to fix these.

First unbolt the cable from the pinch bolt on the derailleur. The cable threads through the bolt itself, and is sandwiched by this stupid metal clip that serves only to fray the cable and make it difficult to remove. Unscrew the nut holding the cable on there, then pry the metal clip apart with a flat screwdriver. This is what I'm talking about:

Once the cable is out (feel free to cut it if the cable doesn't slide out), remove the tension pulley using either a 9mm wrench or socket:

Now slide the chain off the remaining pulley and loosen the bolt on the derailleur's claw which holds it onto the bike's frame (if you have a chain tool, it may be easier to just break the chain rather than remove the tension pulley right away). The derailleur should now slide off the frame, and you can begin cleaning the parts:

 

The pulleys on these derailleurs are cool because they have little ball bearings in them. Unfortunately they tend to get gunked up and don't spin freely. They can be disassembled by putting two 13mm wrenches on the flat parts and unscrewing. Here's a closeup:

Taking the pulleys apart isn't necessary however, and the guide pulley (the one you didn't remove yet) doesn't come off without removing the rest of the derailleur cage. Instead I recommend just dripping some oil into the pulley bearings. The pulleys should spin easily afterwards. The rest of the derailleur can be completely disassembled, quite unlike modern derailleurs. The steel plates that move the cage back and forth are secured by nuts and bolts, unfortunately these tend to loosen up during use.

The barrel adjuster screw may seize in place on these derailleurs. If it is hard to turn, use pliers to unscrew it completely, then clean and grease the threads before reassembling. The spring can even be omitted if the adjuster is especially hard to turn. This screw is only used to take the slack out of the cable upon reassembly.

Here is the nearly finished derailleur in all its glory:

Make sure the pulley cage's spring is contacting the stop. If the cage just flops around, rotate it counterclockwise until the spring catches the stop. The derailleur is installed in reverse of its removal, by sliding the claw back into the frame dropout, removing the tension pulley, looping the chain around the guide pulley, then reinstalling the tension pulley with the chain in place. Again, you can also break the chain if you have the proper tool, and reconnect it once the derailleur is back in place.

 

Finally, thread a clean and oiled cable through the outer housing pieces and bolt it onto the derailleur. Check the limit screw adjustment with the back wheel on, and make any adjustments if necessary. The screw on the front of the derailleur is the high limit screw, and the long one on the bottom is the low limit.

With the derailleur reinstalled, it's a good idea to clean the plates that move the pulleys back and forth. I like to shift the chain into the biggest gear and use a flat screwdriver to scrape the caked on grime from the derailleur's moving parts. Lubricate each pivot point with oil or WD-40 so that the mechanism can move freely:

Pedal Installation

Pedals have a few quirks. There are two different thread sizes (1/2" and 9/16") depending on the type of crank they're used on. Most bikes use the larger 9/16" size, which is the size shown in this tutorial. These are installed with a 15mm wrench. The 1/2" size are used on bikes with one piece cranks (old Schwinns, BMX, crappy department store bikes). Regardless of size, the left pedal is always reverse threaded to prevent it from unscrewing itself in use. Keep in mind however that pedals are not self tightening, and that loose ones will strip out the threads in the soft aluminum cranks, rendering them useless. With that out of the way, let's begin:

 

Right side assembly:

 

Left side assembly:

 

Finish tightening each pedal before moving on to other tasks. This way you won't forget to tighten them properly. There should be quite a significant amount of force holding them in place. Obviously you don't want to overdo it, but in this case undertightening them can be just as bad. Cheers.

Shimano Uniglide

Lots of 80s bikes have a unique type of cassette that uses a threaded cog on the end to secure the gear cluster to the hub. This is called uniglide, and was Shimano's first attempt at making a cassette hub. These cassettes have twisted teeth, without cutouts or special shift ramps. Here is a very early 6 speed uniglide cassette hub from 1982:

 

Notice the threads on the outside of the freehub body. These are for the last cog which holds everything else in place. To remove the cassette you can use 2 chain whips to unscrew the smallest cog, or you can leave the wheel on the bike, shift into the biggest gear, and put the chain whip on the small cog. If you pedal forward with the chain whip secured in place, the cog will unscrew.

The last photo shows the complete cassette. Notice how there is only a dustcap at the front of the freehub body. This means that you can't install a modern hyperglide lockring to this freehub body. Some late 80s/early 90s hubs have threads for both cassette types. 

There are lots of ways to modify a uniglide cassette hub. The threads on a uniglide hub are the same as a standard freewheel, as well as a bottom bracket lockring. If you lose the smallest cog you can still use a bottom bracket lockring to hold the rest of the cassette to these hubs. You can also add a track cog to these threads to make a cheap singlespeed bike. Also keep in mind that uniglide cogs can be installed backwards if they wear out, thus doubling the life of the cassette.

Finally, you can install a newer hyperglide cassette to a uniglide hub if you grind off part of the wide spline on each gear (Hyperglide cassettes have one spline that is thicker than the rest in order to line each gear up with the shift ramps on adjacent gears. Uniglide cassettes have a uniform spline pattern). If your hub doesn't have the inside threads for a hyperglide lockring, you can just omit the smallest cog and use a bottom bracket lockring to secure the cassette. These hubs have lots of little quirks to them, but are definitely worth keeping around if you find a bike with one.

Starter Motor

Remember when this blog used to be about bike repair? Well I haven't had to do any major repair work on my own bikes yet, so here is an automobile starter that I took apart (I need a life..). In case anyone cares, it's from a 3.0 liter OHV Ford Taurus motor. These are ridiculously easy to replace since they're held on by 2 easily accessible bolts. Don't get me started on the DOHC motors though ...

Here's a better shot with the brushes removed:

 The solenoid can be taken apart too but it's really not that interesting. It's just a magnetic on/off switch. When its "on" the starter will rotate. When you turn the ignition key, the solenoid activates the motor and your engine can start.

I got bored today

Ever wonder what a 25 year old oil filter looks like inside? Here's an old AC Delco PF-47 that's been in my garage as long as I can remember:

It looks like it belongs on a World War II fighter plane. Here's the filter cut open: 

The paper inside looks messy cause I was trying to pull it out. Here it is in all its glory:

Looks pretty good despite me hacking it to pieces. Anyway there's more bike related stuff on the way, possibly with better photos (stupid cellphone camera).

Stripped Pedal Threads

(Yes, that's a spark plug.)

If you strip out the threads in the right hand crank, you can use a 14x1.25mm spark plug thread repair kit from a car parts store to fix it. Pedal threads are normally 9/16-20 tpi, but the metric size is actually close enough to work. If you strip the left hand crank, you can theoretically still use that kit but you'll need another right hand pedal and some threadlocker (you're better off just replacing the left crank).

Rust Removal

There's a really easy way to remove mild to moderate surface rust from steel. You simply rub a piece of wet aluminum foil over the rusty part and it should become shiny again. This works especially well on chrome parts.

Rusty:

 

 

  

Shiny :)