Tealc

Hi,

I just got an old bike from a friend. The shifter for the front derailleur does not work, it does not lock the tension when pressed (the derailleur works OK), which means that I can only use the smallest gear in the front derailleur. The problem is that the system uses Shimano total integration brake levers/shifters Exage 300 LX, which I could not find anywhere (only the derailleurs can be found on eBay). I suppose I have to change the full brake/shifter system, but I have no idea about the compatibility of newer Shimano shifters/brakes with my bike (I would rather not change the brakes and derailleurs themselves as they work fine). Sorry, all this is new to me. Could you give me some advice on what to buy to fix the problem?

Kind regards.
Tealc.

Bill Kapaun

FIRST!
Flush the innards with WD-40 or a similar solvent to dissolve the old, hard grease so the pawl can release.
Let sit for a bit and then slowly work the lever to the top gear position and slowly back down.
Repeat 3-4 times.

Tealc

Thanks for the quick reply. Yesterday I opened the shifter but the access to the interior was quite limited (for some reason it cannot be disassembled without removing the cable attached to the derailleur). In any case, I will do as you suggested, maybe the lever lock is stuck in unlocked position due to old grease. However it looked quite clean inside, no grease, so somebody might have done that before with no luck. Any other idea in case that fails to work?

VegasTriker

I had to look up what a Shimano Exage 300 lx was. The pictures and explanations are a 3X7 with Rapidfire shifters. It isn't an expensive model and still appears to be available. Your replacement just needs to be Shimano compatible and have 7 speed indexed shifting for the rear derailleur. There is a YouTube video on how to fix one You can find a pair of replacements on eBay or Amazon. Examples:
$18 postpaid https://www.ebay.com/itm/175252024360
There are similar ones on Amazon but the sellers do not specify Shimano compatible so you might want to ask that question before selecting a pair to buy'

Bill Kapaun

And you know for sure the OP has V brakes?

Tealc

Thank you all for your help. It would be much easier if I could post pictures! I cannot because I am new to the forum.

My shifter is not so easy to disassemble as in the video, but I could try harder next time, now that I saw what could be the culprit.

Regarding the purchase of new ones, I will check if I can get those you mentioned, but here in the UK.

Bill Kapaun

https://www.sheldonbrown.com/gloss_ca-g.html#cantilever
https://www.sheldonbrown.com/gloss_da-o.html#directpull

Better determine the brake type because they use different amounts of cable pull.

FBinNY 

Don't waste any time shopping or fretting about compatibility until you've given Bill"s "Flush and work in" advice a good test. These shifters use an escapement controlled by a very light spring. The least mount of internal stickiness causes the problem you're experiencing. So, fo the flush, and light a candle to whatever gods favor your bikes.

Of course, you may be SOL, but you can cross that bridge when you get to it.

Tealc

Good! I'll try tomorrow. Maybe a bit of electric contact cleaner first, then WD40. My only concern is the lack of clear access to the internals, so I cannot give a good shake to the mechanism with a wire like in the video. Many thanks for your help, I'll post some feedback after tomorrow (hopefully).

andrewclaus

About two minutes into the video above shows the crux of the matter. The spring-loaded ratchet pawl is probably frozen on its shaft, and WD-40 isn't a good solution for that. If you need to pull the cable to remove the cover on your model, go ahead and do it--it'll be worth it. Then put a small squirt of penetrating oil on the pawl, and use a dental pick or homemade tool like in the video and work it for a few minutes until it's free. I do this nearly every week in the non-profit shop where I volunteer.

Sometimes WD-40 works by itself. As said above, light a candle and if you've lived a good life maybe it will work.

dedhed

Make sure any contact cleaner is "plastic safe"

Tealc

Thanks for all your guidance and support. Today I removed the cable and fully opened the shifter. It had some sticky stuff, but somebody had tried to remove it because it was not so bad and it had other oil in it. I did a more thorough job by sparingly using the contact cleaner and a cloth until all the small locks moved freely. The levers started working as expected, and after the contact cleaner was evaporated, I used WD40 and moved the mechanism many times up and down. Then I added thin lubricant oil (3 in 1 type for sewing machines) and reassembled the cable (a bit of a pain!). The shifter goes up the three gears (front derailleur) perfectly, but when I try to go down 1 step from the big gear (to the medium gear), it seems to do only half of the movement that it should, and the chain does not move to the medium gear (it just starts rubbing the derailleur). Pressing the shifter again moves the chain to the small gear correctly. But when going in the other direction, the shifter does the right amount of movement and the gears shift correctly at all the steps. I might have not cleaned everything fully, but I think it was correcly working for all the steps before assembling the cable. In any case, a minor problem and a big saving not having to buy new brakes/shifters. Thanks again!

P.S. Yes, the contact cleaner is just some type of alcohol, i.e.plastic safe. What it is dangerous is the typical brake cleaner, which is an organic solvent like acetone (it kills plastic, rubber, etc).

Andrew R Stewart 

I don't recall if these front shifters had a trim feature, some of the early Shimano units did, most all modern versions don't. I have seen gummy and flushed/lubed trim featured shifters that the trim was so subtle a position that the trim didn't consistently work.

My go to solvent had been Safety Klean stuff. Now that NY state has banned that solvent I find it takes longer and more cycles of flushing before the gummy stuff is gone. Compressed air can be your friend BTW during this procedure. Andy

oldbobcat

This isn't brain surgery. Don't be afraid to make a mess.

Tealc

Brake cleaner contains very strong substances that dissolve/damage any organic component, including many plastics. When I opened the shifter, it had a couple of plastic parts. I would not use a brake cleaner that is not plastic safe. It may work better in short term, but it will damage the shifter after some time (depending on the plastic type an the brake cleaner composition, of course). It is like a lottery!

Andrew R Stewart 

True but- Most of the plastics in the history of Shimano STI lever internals is reasonably solvent resistant. I've left many shift pods (road and MtB) in a few solvents with no problems, including the ones from the 1990s that first showed gummy factory lube problems. I know of a few shifters I have reserviced years later (good customers and record keeping sometimes are a good thing) for a second time with no plastic/solvent issues. BUT there is one exception I will mention.

In the mid 1990s there was a version/series that had the shifter (Shimano MtB) enclosed in two plastic clam shell halves with a narrow "sealing" plastic "ring" between the two halves. This cover sealing ring was made of a softer/more flexible plastic then the half shells were. This ring seal would swell with solvent (Safety Kleen in the shops I worked at) and noy be able to be reinstalled with the seals and shell contact edged staying overlapped as OEM did. The solution was to remove the sealing ring before any flushing/cleaning. Of course this means removing the more stable plastic shell halves from the shifter pod and that seal, a lot more work then most will want to try. Andy