Drilling out cotter pins is a pain in the ass. I tried real hard to pound these things out but I ended up doing more harm than good. I tried pounding them out the good old fashioned way but I ended up bended the threaded end one one side and putting a good ding in one of the crank arms. Yeah that last one really pissed me off.
So I broke out the drill and the Dremel tool and went to town. I’ve never done this before, so half of this will be me recalling what I did wrong. The other half will be how I managed to get it right on the second try.
On the first pin I took the Dremel, cut off the threads and started drilling from the narrow end. I started out with a relatively small drill bit mostly because I was afraid to use a bit that was too big I figured this might damage the crank arm or the spindle. This was pretty naive. The spindle is hard as nails, well actually harder. It’s harder than drill bits either way. I think you’d be pretty hard pressed to do damage to the crank arms too but I didn’t get a chance to try.
After drilling my pilot I tried opening it up further with a 3/4″ bit. It kept grabbing the sides and eventually it broke the bit. Not only was I drilling with the wrong sized bits I was drilling the wrong end. After drilling the threaded end I tried again to pound it out. But I then realized that the place I wanted to hit with the hammer was gone, I just drilled it out. Crap. Using a punch I could get enough of a foot hold on the sides to give it a good bang but not enough.
I then took the drill to the other side and made the same mistakes as before (broke another bit). But this time I realized I could get a larger drill bit through. That’s because … well that’s just how cotter pins work. Long story short, drill from the wide end with the biggest bit you can manage (mine was 5/8″). Stay aways from the sides but don’t worry about hitting the spindle. If you do eventually hit the spindle it will guide you further in (remember it’s a lot harder than the drill bit) but don’t go so far you bind the bit between the spindle and the crank arm. After this it was short work banging the pin out once I could find a spot to seat the punch
Notice the hole in the side of the cotter. This is from the drill bit making contact with the spindle. It sounds kinda squeaky when it does but it’s no big deal.
On the second crank arm I didn’t make the same mistake. I went right in with the 5/8″ bit from the wide end. Drilled it as far as I thought I could get away with and then banged the pin out from the threaded end. Short and simple. This goes with out saying but you need a solid place to drill from. Ideally you’d have the whole bottom bracket in a vice but I found it enough to get the frame up on my work bench with the bracket pinned down on a few blocks of wood. I held it down with a C clamp when necessary.
Once the pins are out, the crank arms come right out. To get the rest of the bottom bracket apart it’s just a matter of getting the end caps off. These things are super hard to get a good grip on with your wrench. One of mine was very stubborn and I had to enlist the help of Steve down at Mello Velo.
Best part of getting the bottom bracket apart was finding the crap that was inside of it. I knew something was up since the cranks would barely turn. I guess the bird seed in there was getting in the way. Yeah bird seed. I’m guessing the squirrels must have been hiding food in the frame when it was doing time on a back porch. They could have been dropping this stuff down the seat tube I guess.
Even the spindle had seed stuck to it.
Then it was back to cleaning stuff up, this time the crank arms. They came clean enough but they’re pitted up in spots.
This bottom bracket wasn’t sealed. Just bearings, cups and the spindle to hold them in place. I don’t think you can even replace these things and it’s not worth trying. Mello Velo is trying to track down some sealed bearings that will fit the frame. Hopefully I’ll be able to find a spindle that will work with the new bearings and the old cranks. I don’t want to have to spring for a new set of cranks after going through all of this trouble to keep this bike as original as possible.
More to come.