Front derailleur jammed...

[DrSquirrel]

I can move into the big ring with the shifter and a lot of pressure, but it won't shift down. The cable is freely moving and just releases to slack, I can tap the dérailleur with my foot whilst moving to knock it down a gear.

Whilst in the stand, I try and manipulate it with my hands and its really hard to push the mech down a gear (yes whilst the chainring is turning).

Tried to get some oil down there but no luck - what should I try now?

It's a Deore triple MTB mech...

 

[Gerry Attrick]

I suggest removing it and soaking it in a paraffin bath for a few days. Then scrub it with an old toothbrush, dry off, re-lube and re-install. The pivots have seized probably due to road salt and general muck.

Sorry, "a few days" was tongue-in-cheek. But seriously a good soak, scrub and then working the mechanism by hand until it is free will sort it out.

 

[Crackle]

I suggest removing it and soaking it in a paraffin bath for a few days. Then scrub it with an old toothbrush, dry off, re-lube and re-install. The pivots have seized probably due to road salt and general muck.

Ditto, though last time I used Muc-Off but the toothbrush is the key bit.

 

[DrSquirrel]

Thanks.

I was hoping I could get away without having to remove it, but alas I probably will have to. Hopefully marking the frame up will make it easier to remount with least hassle!

 

[HLaB]

It sounds like the spring (I don't know its proper name is needing oiled) with one bike its exposed and on another bike its got a cylinder like cap around it. A small screwdriver or something will remove it and expose the spring. If you apply lube to that and the pivot points you might get away with not having to remove it; it depends how badly it is seized. Good luck :-)

 

[DrSquirrel]

It sounds like the spring (I don't know its proper name is needing oiled) with one bike its exposed and on another bike its got a cylinder like cap around it. A small screwdriver or something will remove it and expose the spring. If you apply lube to that and the pivot points you might get away with not having to remove it; it depends how badly it is seized. Good luck :-)

It's visible, and I've put oil on it (a few days ago too) and it hasn't free'd any more or less.

 

[HLaB]

It's visible, and I've put oil on it (a few days ago too) and it hasn't free'd any more or less.

Pity :-(

Probably less than ideal but I've sprayed WD40 on seized things, left them for a while and used a proper lube after and things seem to have worked on my cheaper bike. On my sirrus however when it seized I took it off to give it a good clean and lube and touch wood its almost as good as new.

 

[DrSquirrel]

Sorted, took off the bike and soaked in paraffin - wasn't working, mounted it to a post so I could manipulate it then realised I was trying the wrong way, a few wiggles and it was free, gave it a bit of lube whilst moving it around and its as good as new.

Need to get it back on the bike now!

 

[fossyant]

Good news. Front mech's are hard to break ! Remember to squirt a bit of WD40 on the pivots say once a week in bad weather/winter.

 

[cyberknight]

Bit of a thread resurrection !
My front mech has seized up on the boardman, currently sitting in a margarine tub in a bath of gt 85 , fingers crossed

 

[ColinJ]

I had the same problem on my rear mech, caused by leaving salty grit on it after a couple of recent wintry rides. A good clean, relube and working the mech back and forward by hand seems to have fixed it.

 

[cyberknight]

I had the same problem on my rear mech, caused by leaving salty grit on it after a couple of recent wintry rides. A good clean, relube and working the mech back and forward by hand seems to have fixed it.

no joy so far , taken off the bike and lubed /cleaned and you can only just move it and the spring does not pull it back at all.

 

[cyberknight]

And its still stuck

 

[gbb]

And its still stuck

Which make FD ?
My old Sora FD was very prone (every winter) to siezing up. I commuted daily, all weathers and the pivot used to get dry. On the old style Sora , you undid (not removed, just loosened) the rear facing pivot bolt, sprayed it liberally with WD, work the bolt and mech a bit and it would free up every time.

 

[Gravity Aided]

And its still stuck

Anything stuck where the limit screws hit the limiting cam? I had that once, pulled the chance piece of tarred gravel out and it worked fine. Your results may vary. Otherwise, penetrating oil may be needed.