STOP! Don’t take your shifter apart until you have positively identified that the problem is internal and can not be solved or helped by spraying lubrication into the shifter.
Background: My brother in-law brought his bike over and mentioned that the shifting wasn’t working. He had purchased the bike used sometime in the last year but this was the first time I had seen it. Thus I don’t know the full background of the bike but here is a general description. The bike had a full Shimano 105 ((speed 5500 series) buildout, it was a 1999 Raleigh R600 (2) based on some BikePedia research. It had an Ohio bike shop sticker on it and there was some rust on the brake springs and stem. Bare aluminum by the cranks looked slightly corroded. So to me it looked like the bike may have spent some time outside, unprotected or ridden in salty midwest winters.
Diagnosing: On the bike stand I pedaled and tried to shift through the gears in the rear (right shift lever). The downshifting clicks (big paddle) were distinct but a little gummy. The upshift (small paddle) didn’t want to click. As I pushed the small paddle the big paddle wanted to follow. I then unhooked the rear derailleur cable and removed it from the shifter so there was no tension from the rear derailleur. There wasn’t much improvement in how crisp the shifting felt. When pressing the small paddle the large paddle still wanted to follow. The large paddle had to be held in place while the small one was pressed in order to get a click/shift. This pointed towards an internal problem.
Lube First: Since the action felt gummy and there was evidence the bike may have been left outside I suspected the internal lubrication in the shifter was no longer in good shape. At this time I tried spraying some PB blaster (which I bought based on internet recommendations) into the shifter lever and working it the shifter though the range of clicks. In a best case scenario the action would have freed up and the shifter been usable.
I opted to to take a more extreme solvent to the shifter, some aerosol carburetor cleaner. This stuff is nasty. I had gloves and glasses on. I watched some of the clear coat bubble off the aluminum shift/brake lever. I suspect this could also harm plastic or rubber items as well. I regretted using the carb cleaner at this point. I wiped as much off as I could and tried spraying more PB blaster in and the shooting some BikeAid lubricant in. This process was messy. It was hard to tell if the solvent/lube was getting fully into the shifter. I think this process did loosen up some of the gummy grease but as I would later find out there was more to the problem.
Going Deeper: At this point the shifter was still not working and I wanted to see inside of it. I’d found enough pieces of information online to suggest that is was possible to take apart (and reassemble) an STI shifter but it was also possible that I would end up losing parts or never get it put back together. I gave myself a quick pep talk, listened to John Henry and decided to give those Japanese robots a run for their money.
Preparing to Disassemble: I made sure to have a clear and clean work place on my workbench with some fresh paper towels down. For tools I had a small philips, ⅜” punch, allen wrenches, 8mm and 9mm wrenches, dental picks and a roll pin. I had teflon grease for reassembly. I shifted to the highest gear position to release as much initial spring tension as possible. The Front/Back and Top/Bottom of the shifter all refer to the viewpoint of a rider sitting on the bike. The shifter was primarily disassembled facing the front of the shifter though so Left/Right references would be reversed from the riders perspective.
Disassembly: I took the lever off the bike and removed the rubber hood (3485, 3486). I pried off the plastic 105 cap that covered the front of the shifter (3487). I backed out the grub screw (3489) that kept the pivot in place and used the punch to drive it out (3491). There is a coil spring that helps the brake lever return. Take note of its position (3493-95). Remove the brake cable stop pivot (3496). The pivot has a plastic and metal beveled washer on each side (3502-04)
At this point the brake components have been removed from the shifter (3505-06). On the front of the shifter there is a philips head bolt that holds a black plastic bracket that the 105 faceplate was formerly mounted to (3508). Removing this bolt will not release any springs. This reveals an 8mm nut (5510). This nut holds the large shift paddle/brake lever on the center column of the shifter but there is a second screw on the back we will get to in a moment. Remove the metal washer with the cross shaped center and the nylon shim using a pick (3511, 12, 14). Notice the end of the coil spring that will release in a moment (3511).
Turn the shifter over to see the back and there is a philips screw that needs to be removed (3515-17). This will allow the large shift paddle to come fully off and release the first coil spring (3519-21, 24). Some shots of the lever disassembled to this point (3526,28,29,31). Use a 9mm wrench to take off the next gold nut (3532-33). This frees rest of the shifter components to come off the central column (3534). The first pieces to come off are a metal plate, a round grey plastic plate and the large gray plastic housing. As the large housing comes off a small spring will release (3535-36). Photos 3543-53, show the shifter with the housing remove. The pawls and ratchets wheels are all still in place though so this series should be helpful for verifying reassembly too.
I donned the nitril gloves and put on my glasses again so I could use more of the carb cleaner to try to clear out some of the gunk before continuing to remove parts. During this cleaning some of the pieces began to slide further off the central column so not all of the parts are in alignment in these photos (3554-57). The next parts to come off are the ratchet wheel assembly, this is also what holds the shift cable head (3558-59). There is a coil spring sandwiched in this assembly that causes the ratchet wheel to want to return to the high gear position (3562). The silver ratchet wheel has teeth on the right side (NDS) that engage the twin pawls on the top of the shifter. Behind this is a pair of gold ratchets that have a black metal piece in between (3562). These pawls are on the left (DS) of the shifter and engage the pawl on the bottom of the shifter. Photo 3563 shows the last of the ratchet wheel assembly removed, the pawls are still in place. Photo 3569 shows the parts removed at this point.
Photos 3571-72 show the orientation of a few pieces that need to go on in a specific way. Pulling a black metal piece off reveals a thin silver washer (3573). The next few photos show how warped and bent this silver washer was. I suspect that this was the culprit or evidence of the interference that was going on in the shifter. (I accidently changed the name of these photos before I realized the sequential numbers were easier to reference). The last parts on the column are a silver ‘comma’ shaped piece with a cross in the middle, a ‘c’ shaped spring and one more thin silver washer with a tab (3585).
Assembly: First off, Sorry. There are only about ten pictures of the assembly process. It was very iterative. I had to repeat a lot of steps as things fell out of alignment. When I would accomplish a sub step I wouldn’t want to let go if the parts and take a picture since there would be a chance all of my work would come undone.
Starting with the first three pieces, silver washer, c-spring, and comma, make sure they align like shown in 3588-89. I unhooked the springs for the pawl eventually to keep it out of the way. It was easy to reinstall later. I then put the same bent washer back since I know there are no spare parts. I also didn’t want to keep the shifter apart to look for a substitute part and then forget how to put it back together. Added some new clean grease though (3593). Picture 3594 shows another milestone. This took a little while but I figured out to put the 1st gold ratchet wheel and the black spacer on first. Next put the second gold piece already mounted to the silver ratchet wheel with the coil spring and holder in place. These 5 parts go on as one. Keep the spring pinched in place and slide it in the cross column with the cable head holder in the 2 o’clock position. Rotate CCW, you’ll feel the spring tensioning, until you get to 10 o’clock and then things should press together. More shots of this phase are shown in 3595-97.
I missed a photo of the next stage in assembly, that is re-loading the small spring that is hiding behind the silver plastic cover (3535-36 disassembly). I used the roll pin to pull the spring down and then snap the gray plastic cover on. By the time I had it finsihed it was all covered up (3599). The gold plate and nut held everything together at this point. The last step was pretty much to put the large shift lever on. It has one large coil spring that needed to be pre-loaded. This was easy after all the prior steps and because I had a small roll pin. Unloaded, the spring tab rests in the 10 o’clock position but needs to be moved CW to the 2 o’clock position. Once there, pinch the lever in place and it will hold. Put the outer nut on, put the philips screw on in the back, and then the tense part of the shifter assembly is over. After that put the shifter back onto the brake mount and replace the rubber hood. The shifter should be in the highest gear position. Try clicking through the range.
Verdict: The shifter still sucks. I put it back together correctly (which was an accomplishment) but there was too much internal friction still. The clicks are there but the internals are not free to move about without impacting other internals. Unfortunately disassembling, cleaning, and regreasing couldn’t solve the problem in this case. I don’t know is something else was bent or if i tightened the two inner nuts too much. It was still an interesting learning experience though.
Tagged: , shimano , sti , sl-5500 , 105 , lever , right , rear , brifter , brake , shifter , disassemble , diy , repair , overhaul