mcours2006

I took apart a non-functioning 7900 left-side shifter hoping I could somehow repair it. Turns out the culprit was a corroded spring that had snapped. I've scoured the internet but no luck. It's such an obscure piece that I doubt one could find it, unless I get another non-working shifter and cannibalize it.

Anyway, I know it's a long shot, but any idea on how or where I might get something like this:



The penny is just to show the size.

Andrew R Stewart 

The only way to source this part is to get a donor lever. Shimano doesn't stock the internal parts as they never intended the STI levers to be serviced. Andy.

mcours2006

I figure as much. I've contacted a few small engine repair shops that might carry something similar that might do the job. Heck if a $2 part can bring life back to a $270 shifter, why not.

fietsbob

Springs like that are steel wire that is wound first then tempered .. You can always try a DIY Project.

HillRider

Not quite DIY but most hardware and home stores have a collection of various size springs. Take the broken one there and see if you can find a near match that you could "customize".

mcours2006

Hardware store is a good idea as well. I will give that a try.

The small engine store could not help me. They had springs, but none that were the right size nor with enough tension.

dedhed

My "Good" hardware store has about a hundred different springs. I also have a coffee can full I collect when tearing things apart doing "forensic mechanics"

mcours2006

Well, if nothing else at least I got some experience taking apart a shifter and putting it back. That skill might come in handy one day.

dedhed

Can you bend a new end on the existing piece of spring? Maybe not as much tension but might work.

Shimano Dura-Ace 7900 2x10 Speed STI Shifter | Chain Reaction Cycles

mcours2006

Yeah, already tried to bend the old spring. It's so far corroded that it just broken into two pieces when I applied a bit of force.

Crankycrank

Generic springs can be found. Just measure the inner and outer diameter of the spring and number of coils, find something with a few extra coils so you can bend the ends to your liking (or if you botch the first attempt you'll still have some extra spring to work with) and just cut off the excess.

mcours2006

I'm going to head to check out a few hardware stores tomorrow to see if I can find something suitable. Trimming a longer one is a good idea.

The spring is a return spring for the small paddle lever that sits on top of the smaller downshift leaver. Not sure how much tension is required for this to work properly. Trial and error, I guess.

james_v

Some fishing reels contain a number of very small springs. You might find something at a fishing reel repair shop or even at a sporting goods store that might have spare parts for reels.

Or you may have an old fishing reel at the house that could supply a donor part?

BTW - You do know that Shimano makes fishing reels?

mcours2006

Trust me, I'd already scoured the house for anything that might even contain a spring of that size. I even tried the spring inside a pen. No luck so far though.

Yep. I used to a ton of fishing. Got a few baitcast reels myself actually. I check my older reels to see.

Thanks all for the ton of suggestions.

joejack951

Coil Springs Manufacturer - Stock & Custom - MRO & OEM | Century Spring Corp. stocks a ton of springs. If you can't find something there, making something yourself will be the best bet.