Trek 5900 rear-brake cable stop

thingiverse

I decided it was time to deal with the corroded rear-brake cable stop on the top-tube near the headset before it rotted off and decided it was a good time to document the part just in case I needed a replacement down the road. The image shown with the OCLV Carbon 110 decal is of the cable-stop under the seat. It is still in nice shape along with the clear-coated nude carbon around it. My 2003-2004 Trek 5900 is mostly "nude" (raw Carbon fiber with clear-coat) and USPS decals and silver metallic paint on the front third of the frame & fork. Testors #1830 Lacquer Spray Paint Diamond Dust is a great match for the Trek paint. I'm fussing with the paint while I write this and it may require a clear-coat on top to seal it? The paint was VERY bubbled and chipping on & around the front cable stop. I cleaned it with a plastic brush and water and used a plastic pick to get the paint off the stop itself. Once I removed the bulk of the bad paint I masked around the cable-stop with electrical tape to protect the carbon fiber, and used 220 and 600 grit wet-sandpaper to clean the stop and get it smooth again. Turns out that the stop is aluminum and is secured to the frame with a pop rivet and likely a dab of Loctite 9430 hysol epoxy bonding it to the carbon fiber. While doing this work I also replaced the bottom bearing for the headset and put a bore scope inside the top tube and saw the underside of pop-rivet. (Below is information about the tapered steering tube to compliment the picture in this posting.) The STL file uploaded has been printed and verified for fit (except the rivet through-hole diameter). I would NOT use a plastic replacement and advise using a 3D printing service that offers aluminum. I checked i-materialize and it was about $44. I also had to use a 0.3739 scaling factor to get iMaterilize to see the part as 1 inch long. (The model started with a 1" x 0.5" x 0.4" extruded block and turned into the finished part with about 10 Cut-Extrudes and numerous fillets.) Worth noting that it was very obvious while measuring this part for modeling that it was not designed in a metric system. Lots of its details were very obvious inch measurements. *** The hole for the pop-rivet in my model is NOT correct. Since my cable-stop is still attached I had no way of knowing the diameter of the through-hole in the frame, or the rivet body. You will have to take care in drilling this to the proper size to pass a rivet through. And, if you're into the repair that deep you likely also have the fork removed and can shake out the remainder of the original rivet. If I had to install a new stop from scratch I'd be liberal with the epoxy and use a bent paperclip to smear the inside of the top tube around the rivet hole to seal any stray fibers surrounding the hole. *** *** FYI - there is also a lower bearing headset protector design for the Trek 5900 ***