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Discussion Starter · #1 ·
So I just bought a bike off someone and it will be my first mountain bike. Took it to a bike shop to get some advice about it and guy said the left shifter was not working.

He said the part was only around $20 and then another $20 to pay for labor. I was wondering if this is something I could do on my own?

How hard is it to replace and do I need any special tools? The guy did not want to give me much info some reason except that he said I would mess it up if I tried.

The bike is a Trek 4900 btw and only paid $220 for it so hopefully it will be a great starter bike for me.
 

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The price for the shifter sounds about right. The prices of shifters can range from about $20 to $200 per shifter new so it just depends on the quality that you'll be getting. The labor sounds a little bit much but only by maybe $10 or so. You could attempt to do it yourself but you would have to deal with getting the grips off, connecting cables, and then tuning your derailleur. I know when I was a noob I would not have been able to do all of these so I'd let the guys at the lbs handle this one and you can learn on down the road by tinkering here and there and pick up knowledge as you go.
 

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Discussion Starter · #4 ·
Well the only thing that I would be unfamiliar with would be tuning the derailleur. I rode BMX for a couple years but it still amazes me how much more complex mountain bikes are.

When tuning the derailleur is it difficult or something i could read/watch and then learn?
 

· Fat-tired Roadie
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Try flushing it out with WD-40. There are some more extensive things you can try too. Often, flushing with something will give you another few seasons.

If you do have to replace the shifter, neither the price for the part nor the labor sound too far off. Minimum labor charges in shops around me are usually $15, which buys you up to fifteen minutes. Replacing a shifter should fit inside a minimum labor charge.

Shifters are not that hard to replace yourself, either, if you take your time, follow directions, and know how to use a screw driver. Check out www.parktool.com for illustrated instructions for most of this stuff.
 

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As mentioned, it's probably just gummed up. Since it's not working, you have nothing to loose by trying to repair it.

You may get it to loosen up without removing it. Loosen the bolt that tightens it to the handlebar and move it away from the brake lever so you have access to it. Remove the small screws and lift the cover off.

If you have an air compressor to blow it out, you can spray it with a degreaser. Otherwise, just spray it with some lube as you work the triggers. The Dupont Dry Lube at Lowes and some hardware stores is a good all around lube for chains and the pivot points on your derailleurs. It should work well.
 

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Discussion Starter · #9 ·
AndrwSwitch said:
Try flushing it out with WD-40. There are some more extensive things you can try too. Often, flushing with something will give you another few seasons.

If you do have to replace the shifter, neither the price for the part nor the labor sound too far off. Minimum labor charges in shops around me are usually $15, which buys you up to fifteen minutes. Replacing a shifter should fit inside a minimum labor charge.

Shifters are not that hard to replace yourself, either, if you take your time, follow directions, and know how to use a screw driver. Check out www.parktool.com for illustrated instructions for most of this stuff.
Appreciate the tips and pointing me in right direction. Will give it a go tomorrow and if I have any issues will post some pics with questions.

Any specific tools needed or will basic tool be enough?
 

· Fat-tired Roadie
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Did you find instructions on Park Tool? They typically tell you exactly which tools you need.

Should only be a screw driver and the appropriate Allen key. Pliers might be helpful too.
 

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You will need to replace the cable as well. The old one will probably have a frayed end and will be hard to push through. To push the new cable through the shifter, you need to switch shifter to the lowest gear (smallest chainring). Anyway, it is a good idea to replace the cable once in awhile.
Also, you will need a cable ending and a tool to secure it to the cable (my personal secret - I often use an electrical cable ending of appropriate size and a regular tool to press it onto the cable). One more tool you need is, of course, a wire cutter.
 

· Fat-tired Roadie
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I've always been able to secure the purpose-built cable end with my pliers. Needle-nose are a little better.

Good that you remembered the cable - I was thinking "shifter shifter shifter," I guess.
 

· Picture Unrelated
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Replace the cable housing along with the cable since you have it apart already. Depending on the shifter, it may come with a cable or cable and housing already.
 

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Brambled said:
I feel like this may be over my head when it comes to replacing entire cable. Was hoping I could just swap out shifter and be fine.
It's probably not over your head if you're even a bit mechanically inclined and are willing to do a bit of reading. Park Tool is a great resource for stuff like this and the forum can answer any problems you have that Park can't. If you really think it's beyond your ability then your shop should be able to knock it out quickly.
 

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when you get the plastic case open to expose in the internal parts of the shifter, BLAST and saturate the internals of the shifter with wd-40 or a similar solvent or a fluid lubricant. work the levers on the shifter to make everything move around to distribute the fluids. when it's clean and working, drip some light lube like Triflow on all the moving parts to keep them from rusting and keep them moving.

also, there's a little pawl on a spring that snaps into the teeth on part of the shifting mechanism. when you push the shifter up a notch, the pawl clicks in and keeps the derailleur on that gear. oftentimes, that pawl is sticky or frozen, which is what keep the derailleur from working. when you flush the shifter, make sure you free up that pawl. work it back and forth with a tiny screwdriver or an awl or a spare spoke until it moves freely.
 

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Discussion Starter · #19 ·
So finally grabbed a few pics of the bike.




I feel good about replacing it now because I saw how the wire connected to derailer and looks very simple.

But I did run into a problem. I could not figure out how to detach the shifter from the cable. I took out the obvious screws and took plastic top off and I could see inside shifter; but then I could see no obvious way to detach it from cable.

The upshift lever is completely stiff and will not budge at all. It didn't look dirty on the inside and the downshift moved freely but doesn't do anything.

If it would help any I could get a few pictures of the shifter when detached from bars and opened.
 

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Brambled said:
But I did run into a problem. I could not figure out how to detach the shifter from the cable. I took out the obvious screws and took plastic top off and I could see inside shifter; but then I could see no obvious way to detach it from cable.

The upshift lever is completely stiff and will not budge at all. It didn't look dirty on the inside and the downshift moved freely but doesn't do anything.
The cable feeds through the shifter, there might be a small rubber plug with a screw head on it, take that off. Otherwise, you should see a small hole on the shifter on the stem side, under the bar. Shift into first gear and you should be able to feed the cable back out of the hole.

Your stiff lever is probably due to you not pedaling the bike while attempting to use the shifters. If that's not the case, just spray the crap out of the shifter with WD-40 or Triflow and let it sit a while. The pawls should loosen up after a day or so and it should start working properly.
 
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