Simano ST-M738 LH Front Derailler Chain ring Shifter Trouble

[FlugelHound]

Im having trouble going from mid ring to big ring.
the thumb lever pushes all the way forward with little resistance then i release my thumb then have to push again only then does the front mech move and chain shift up to the big ring.

Thinking back I seem to remember having some Pawl Ratchet trouble with this shifter but not sure.

The chain runs fine on all three rings and the front mech ends up in a good position for each ring. But shifting up to big ring requires a full lever push then a little push.

So, im wondering if this is a common issue?
or
Ive cable stretch?
or
My ratchet mechanism is broken?

any ideas guys?

The bike is a Proflex 855

Cheers Fluges

 

[jax13]

the mech seems fine if it sits in position once the shofter gets it there so the issue would more than likely be shifter / cable related.

before you strip anything down i'd check your cable & try & set up the mech again. if you still have no joy then move on to the shifter to see if it needs a bit of a service or a replacement part / unit.

 

[FlugelHound]

New Old SHIMNAO DEORE XT ST-M738-A 24SPEED

£44.00 got me a pair of replacement
SHIMNAO DEORE XT ST-M738-A 24SPEED
shifters c/w cable from ebay.
Fitted them and shifting is now sweet.