Originally Posted by
bsker
Hello all,
I'm working on an older MTB - mid-90s perhaps - and it's got Shimano m739 components ...
I'm looking for replacement parts for the FD and the right 8-spd shifter. I've found parts on ebay, but I have a couple of questions:
- the FD I need is for a 31.8mm tube, but the one I found on ebay is a 34ish with a shim ... are shims a reliable way to install a derailleur, or are you just inviting slippage?
- I can't seem to find the right shifter - only the left - the right shifters I've found on ebay are contained in sets and the entire set is going for $150-200+ ...
Speaking of the shifter ... any repair ideas? When it's off the bike and detached from the cable, it works and indexes fine, but when it has tension on it, it sounds like it's stripped ... is there a way to get in and only repair the innards without replacing the entire shifter?
In any case ... I found a right shifter for an m738 ... how can I determine if this is compatible? I've got v-brakes on it.
Otherwise - any of you know a good source for some of these older parts? I'm pretty new to diy bike repair stuff.
Thanks in advance for your advice,
bsker
In general, the innards aren't repairable by ordinary mortals. There's been some people who have done it, so it's not
impossible, but it's not something I would try myself.
You can try to gain access to the mechanism by taking off the indicator and the outer housing. Since it "sounds" stripped, I would look for pieces of broken-off cable inside it.
Also, clean it out thoroughly and lube with light oil before reassembling. Many old Shimano shifters get sticky due to old grease. A good cleaning keeps them working.
Here's an exploded view:
