Advise on opening this Shimano Thumb Shifter to replace cable

[DHart]

This is the Shimano SL-MT32 shifter on my 1991 Stumpjumper. Can anyone advise on accessing the cable inside, for replacement? There is a large screw on the bottom of the shifter housing, which I'm guessing is the only way to open the shifter, but wanted to check with those who have more experience with this than I have.

I don't know why Shimano abandoned this thumb-shifter style, as it works so perfectly. At least... I am so accustomed to it.

Awesome bike, BTW! I love it. Still runs and rides like a smooth champion.

I'm planning to update it into a city bike... new 1.75" road tires, more upright sitting position, and new brakes. I may have to replace the cables when going with more of a higher, pull back handlebar, but the Deore SIS shifter and DX derailleur are functioning absolutely flawlessly.

 

[bikeworkshop]

Dont open it!

The cable just pushes out.
No disassembly necessary.
If it's stuck, a drop of oil and twisting the cable a little should get it moving.

 

[bikeworkshop]

Shimano abandoned this style because it becomes less and less effective as you gain more gears on the back
-and when mountainbiking, you don't want to raise your thumb above the bar and lose grip.

A lot of innovations in cycling come from the race scene, simple functionality is often forced to take a back seat.

 

[Markybeau]

Don't open the shifter, there is no need, and you may regret it if you do.

Disconnect the cable at rear derailleur - here


The inner cable exits the shifter at the dimple - here

Once disconnected it's relatively easy to remove.

 

[Raumer]

As said above the cable will push out. The easy way to do it is:

Disconnect cable from the derailleur
Push shifter the whole way out - away from the bar
Push it back a bit and the end of the cable should pop out
If not pull the outer away from the shifter and then push the inner cable in to the shifter
Extract cable
To fit new cable push the lever the whole way out
Feed cable through the lever
Then fiddle until you can feed the cable through the body and the adjuster

Hope that helps

 

[DHart]

Thank you all so much. Now I'm really glad I asked instead of just cracking the housing open!

I'm amazed at how smoothly and flawlessly the SIS shifter and Deore derailleur functions... after all these years!

 

[bikeworkshop]

You wait 20 minutes for a bus and then 3 come along at once

That's a high quality shifter and originally cost the best part of a day's wage.

 

[DHart]

You wait 20 minutes for a bus and then 3 come along at once

That's a high quality shifter and originally cost the best part of a day's wage.

Right! Watching that YouTube video, I can see that some engineer really earned his pay designing all the parts that make up the shifter. It seems better quality than the seemingly cheap/plastic modern day Deore shifter with its two under bar levers on my Trek Roscoe 7.

 

[Tootyred]

Welcome to retro bike parts. Well engineered, solid, last a lifetime.

Sadly the industry decided that cost was more important than all the above

 

[bikeworkshop]

Not totally the industry's fault... customer likes cheap!