Shimano Altus shifters not working

[Alan O]

Hoping I can pick a few knowledgeable brains here...

I just bought an old Grisley MTB, in very good cosmetic condition but with gears not working - at £30, I couldn't say no. (Big knobbly tyres are in very good condition, but I'm probably going to replace them with something a bit smoother and use it more as a hybrid than for serious MTBing)

Having got it home, the problem seems to be the shifters. They're Shimano Altus 7/21 speed indexed jobbies, and only ever having used friction levers I really know nothing about how they work.

When I try to use the levers, there's no resistance and they just flap about. Occasionally with the rear shifter, if I jiggle it about a bit I can get it to 'catch' on some resistance and it clicks up one step and then the other lever will drop it back, but that's the only life I can get out of either of them. The derailleurs look good and move freely - they're just a bit dirty, and my first job will be to give it all a proper cleaning.

So the question is, are these shifters amenable to repair or is it better to just get new ones? And then, which new ones?...

It looks like I can get a new pair of shifters for only around £20, but it's complicated a little by the fact that I have all-in-one brake levers/shifters. I've seen such combo things for sale, but advertised as having V-brake levers, but mine doesn't have V-brakes - just regular cantilevers.

Any thoughts would be gratefully received.

 

[gbb]

As it's an old grisly bike, most likely everything is just gummed up, particularly the cables.
Trouble is, to sort it out you need to be able to index or set up gears once you've stripped it down and at least cleaned and lubed everything. There are some good youtube videos to help you with that.
1st, make sure it's not the shifters themselves and unless anyone has a better idea, it needs the cable releasing from the derailleur, then operate the shifter and see if it actually pulls the cable with each click.
Ideally, remove the outer cables, clean and light oil them, reassemble, then try again.
Otherwise, buy new cables and outers...and it may be if you can get new shifters and cables complete, it may be almost as economical to do that.
Clean and lightly lube everything...that's a good starting point.

 

[Alan O]

Thanks for that gbb,

I haven't actually released any cables yet, but I'm fairly confident (I think) that there's a problem with the shifters. I've held the rear derailleur in tension by hand and operated the shift lever - and most of the time there are no clicks, there's no resistance at the lever (apart from what feels like a light spring), and no pull at the derailleur.

But on the odd occasions when the shift lever does engage with something, there is a click and there is a pull at the derailleur, so the cable does appear to move freely.

What does seem strange is that the front shifter doesn't click and there's no resistance there either - it seems a bit suspect for both shifters to have failed together. I'm wondering if maybe they've both been gummed up at some point and have been broken by force?

I've looked around and there are some decent deals on new shifters and cables complete. But there are also some decent prices on a whole new matching set of everything, which I'm thinking might be a sensible way to go - that way I'd be starting with zero wear on everything.

But yes, definitely clean and lube first - though I'm supposed to be avoiding distractions and finishing off a few jobs on my other bikes!

Oh, and thanks for the YouTube tip - I'd be quite keep to learn how to set it all up and index it myself (especially as I like taking things apart and seeing if they'll go back together again).

 

[Ajax Bay]

Take the tops off the shifters and give them a thorough soaking with WD40/GT85 operating the shift lever 'up and down' as you squirt. Put tops back on; leave overnight. Repeat squirting. Any general gumming will be visible and should be cleared by that treatment. You can then decide whether it's that or something's actually broken. Whatever the outcome, definitely new outers as well as new cables.

 

[Alan O]

Take the tops off the shifters and give them a thorough soaking with WD40/GT85 operating the shift lever 'up and down' as you squirt. Put tops back on; leave overnight. Repeat squirting. Any general gumming will be visible and should be cleared by that treatment. You can then decide whether it's that or something's actually broken. Whatever the outcome, definitely new outers as well as new cables.

Thanks. I've just opened the rear shifter and it exposes the mechanism, and it looks clean with no gunk - and there's even evidence of relatively new grease in there.

What I can see (and please forgive the lack of proper terminology) is a cogged wheel which appears to drive the gear change, and a little nub thing attached to the lever that is intended to push the cogs. But it just slides over the cogs without engaging - there's a little spring that holds it in contact with the cogs, so maybe that has weakened (or maybe the edges of the cogs/nub thing have rounded).

I've soaked it in WD-40, but it really doesn't look like gunk is the problem.

(And yes, I'll be replacing all cables as part of my general service, but it does look like there's a problem in the shifters.)

 

[raleighnut]

Thanks. I've just opened the rear shifter and it exposes the mechanism, and it looks clean with no gunk - and there's even evidence of relatively new grease in there.

What I can see (and please forgive the lack of proper terminology) is a cogged wheel which appears to drive the gear change, and a little nub thing attached to the lever that is intended to push the cogs. But it just slides over the cogs without engaging - there's a little spring that holds it in contact with the cogs, so maybe that has weakened (or maybe the edges of the cogs/nub thing have rounded).

I've soaked it in WD-40, but it really doesn't look like gunk is the problem.

(And yes, I'll be replacing all cables as part of my general service, but it does look like there's a problem in the shifters.)

The little "nub thing" is a pawl and should engage to move things, it sounds like it is 'sticky' on it's pivot so spray away (after all it ain't working so you can't make it worse)

 

[Alan O]

The little "nub thing" is a pawl and should engage to move things, it sounds like it is 'sticky' on it's pivot so spray away (after all it ain't working so you can't make it worse)

Pawl! Yes, that's the word I was searching for, thanks! They have them in fishing reels too, so I should have remembered the name.

 

[raleighnut]

Pawl! Yes, that's the word I was searching for, thanks! They have them in fishing reels too, so I should have remembered the name.

Fishing reels made by Shimano by chance.

 

[Alan O]

Fishing reels made by Shimano by chance.

Hehe, yes, I have some of those - but I was thinking of my Abu 505 which has an anti-reverse pawl that a lot of anglers remove.

 

[Alan O]

The little "nub thing" is a pawl and should engage to move things, it sounds like it is 'sticky' on it's pivot so spray away (after all it ain't working so you can't make it worse)

It seems like that diagnosis was spot on!

I tweaked the pawls about on their pivots (there's another one that works in the opposite direction, of course) and sprayed lots of WD-40 all around them, in the pivots and springs. And after repeated rounds of spraying and leaving to soak/penetrate, the pawls are moving more freely and engaging in the cogs. I haven't reassembled yet to check if it works, but it's looking promising - I'll leave the rear one for another overnight soak and will work on the front one tomorrow.

Once I reassemble, can anyone recommend an appropriate lubricant? I currently have some TF2 cycle oil, so would that be good?

On another thing, the brake levers in my combo brake/shifter units are V-brake levers (I checked on the model number, Altus ST-CT90, and everyone who sells them says they're for V-brakes). But the bike has regular cantilever brakes and not V-brakes, and they shouldn't work properly...

And you know what? They don't. With the levers fully pressed and the brake blocks as firmly on the rims as they'll go, I can still push the bike forward with the wheels turning. A set of V-brakes seems to be cheap enough so I'll probably fit those - but what's scary is that presumably someone was riding this bike around like this!

Anyway, thanks again for the help.

Alan

 

[Drago]

Are they they thumb/index finger shifters? surprisingly nice to use.

 

[Alan O]

Are they they thumb/index finger shifters? surprisingly nice to use.

Yep, thumb to shift one way and finger to shift the other. The levers do seem well placed and should be comfortable to use - I'm looking forward to actually trying them!

 

[raleighnut]

I've got them on all 3 of my bikes with flat handlebars on.

 

[CanucksTraveller]

Yes Alan, just normal cycle oil is fine for the shifter internals. Don't use too much.
You're right that those are V brake levers and are only really meant to be compatible with V brakes, I wonder how that's happened?

 

[Alan O]

Yes Alan, just normal cycle oil is fine for the shifter internals. Don't use too much.
You're right that those are V brake levers and are only really meant to be compatible with V brakes, I wonder how that's happened?

Thanks, I'll use a little cycle oil then. And yep, the brakes are a bit of a mystery.