GUIDE: Repairing Shimano RSX (A410) STI Levers

[QuangVuong]

Another guide, now for the RSX STIs. These were in lovely cosmetic condition, and its obvious they did not get damaged over the years. However, the left hand shifter did not click at all. Right hand was very very stiff when clicking. Obvious signs of the gummed up grease.

RSX levers are not symmetrical. The right side lever is different to the left side lever. So I will be going through both left and right sides in this guide.


Well, first things first. Remove the hoods to clean up te lever body and hoods. However it is not neccessary.

Right Side
Use a 2mm allen key to remove this grub screw. THeres a little threadlock so it may be tight.


Get some sort of tool(4mm key in this case) to push out the pivot.


Now you can remove the lever from the body. Use a 5mm allen key to unscrew the nameplate screw. Make sure youre holding onto both the name plate and the lever when unscrewing, otherise there is a possibility that the name plate will go flying off as its connected to a loaded spring.


Carefully lift whilst twisting the name plate off. You will be greeted with this spring. This is different to the assembly of the new Sora(3300) and 105(5500) levers, but exactly the same as the RX100. Id say its much more easy to dismantle and rebuild because the spring is here.


Flip to the backside of the lever, and push over the smaller lever to reveal a Phillips screw. Unscrew this, and be careful of a small screw washer behind.


Now the large lever can be pulled off to reveal the innards. I believe this would be the levers that are the cleanest out of mine, but also the one which has dried up the most.






Proceed with cleaning up the old grease using whatever means you like(I like to use petrol). The dried up grease was some serious stuff. Though a quick soak would allow me to brush if off, but that was not the case. I had to soak it for a couple minutes together with a lot of brushing before it started to slowly clean up. Once cleaned up, apply grease to the pawls.




Left Side
It is not entirely the same as the right lever, but its still close enough to the right side to dismantle.
2mm allen key


Then use some sort of tool to push out the pivot.


Unscrew the nameplate screw with a 5mm allen key. Make sure youre holding onto both the name plate and the lever when unscrewing, otherise there is a possibility that the name plate will go flying off as its connected to a loaded spring.


Name plate can be lifted and turned slightly to remove


Flip to the other side of the lever, and push over the small lever to reveal a phillips screw


Lever comes right off to reveal the innards. Now this side was dirty as! Sand and dirt managed to get inside, and may possibly be the issue.


Proceed with cleaning up the old grease using whatever means you like(I like to use petrol). The dried up grease was some serious stuff. Though a quick soak would allow me to brush if off, but that was not the case. I had to soak it for a couple minutes together with a lot of brushing before it started to slowly clean up. Once cleaned up, apply grease to the pawls.

The plastic cover on mine broke off, which allowed me to clean up a little easier, but I had to glue it back on. Its only there to keep dirt and other stuff out of the lever.






Both levers can go back together in the opposite way they came apart, so back trace, and you shouldnt have a problem.

Finished Product! I chose to polish the exposed body, like on the RX100, and the name plate. I did lose the RSX logo, but in return I got a mirror finish. This time round I chose to not sand off the silver paint and polish, as it was in quite good condition, and wouldve been a hassle for me anyway.






Interesting notes:
- This uses the same hoods as the RX100, which is also shared with the 105 SC levers(ST-1055). I dare say, the 600 and maybe even the DA(6400) levers also shared this hood.
- Back then, Im quite sure these levers were 90% the same. RSX is 7 speed, one less than the others. The RX100, would be the sxact same as the 105. Im not sure on the 600 or DA levers, as I havent serviced them yet. Have a look at the pics from this shifter and compare it with the RX100, and you can see that they are pretty much the same. I would have a hard time seeing the difference, unless I counted the extra tooth for the extra gear.

Oh, and I will offer a service to rebuild STI levers. So far I have done the Sora(3300), 105(5500), RX100, and the RSX as above, but I am sure that I can get around to doing the others without too many problems. I will also gladly take in any broken shifters, or ones that do not work anymore. Please PM me if youre interested!

[bychosis]

Thanks for this guide. As of this morning I was going to trawl the net to find out how to fix up my newly aquired but non working RH shifter. Will be off to the garage with the branded tablet device beside me over the next week or so (This week the MTB takes priority preparing for the Convict 100 on Saturday)

[bychosis]

Finally had a crack at it. Got the right shifter working well, but can't seem to get the left working. Has had degreaser then WD 40 sprayed liberally and then work back and forth to free it up.



The two bits indicated dont seem to have any way of activating when moving the lever, without using a small lever. Once they are moved the spring action releases the shifter as it should.

Any tips on what to do next? I haven't removed the plastic I over yet, probably the next step, I was avoiding this step so far.

[QuangVuong]

In the pic, its in the larger chainring position. When you push the small lever over, that L looking shape in the pic will push onto the left 2 pawls that you indicated, lifting them up. Theres a spring on the inside of the mechanism which will pull it into the small chainring position. Now, here it may not do that. The gummy grease is still around inside the middle of that lever, not allowing it to freely spring back, as that was what I found out had happened on mine recently. But that should be fine. When attached to the FD, the restoring spring in the FD will assist in returning it to the small chainring position. For now, use a free finger or small pointy object to assist it into the small chainring position when you push the small lever. You should see that itll spring back.

The part you indicated on the right has that spring hwich holds the pawl into the gears. When you push the large lever, itll push the mechanism over a click, as per the gear shape. The small lever will shift into the small chain ring, as the pawl will slip over the gears due to the shape of the gears. Nothing activates this pawl. It just moves with the large lever.

This is from just these pics, and what I can remember. I may be wrong there somewhere, but should be pretty much spot on.

[bychosis]

Fixed mine today. I ended up removing the plastic cover to see what it was hiding.

The pic below shows the cam that wasn't engaging, preventing the downshift. I was a combination of the cam not being free enough to move and the spring not being in position. WD40 and plenty of manipulation sorted the movement, it flopped around nicely after luring. The tiny wire around the cam is a light spring, mine was on the inside of the cam, not the outside as it is in the picture as restored.

[QuangVuong]

600 guide is up!
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[martc101]

Thanks QV, great guide.
That first 2mm grub screw can be quite fine, careful not to strip the head!

[bychosis]

My RH shifter stopped working again, so out with the instructions and tools. Unfortunately it appears that this time it wasn't grease, but the cam that engages the bit to drop to a smaller cog won't engage with its catch (terminology?). It appears to have worn down and even pushing on the cam won't get it to release the gear most of the time so adding lubricant won't work. Looks like it may have passed the end of its useful life.

It's shown in the bottom of this pic.

[QuangVuong]

I know of the part you're talking about. And yes, I've since realised that it's that pawl and the one that is directly opposite to it which are the usual suspects that hinder the shifter from working.

I find that even after a long soak in solvent it still does not want to freely pivot, so it needs a bit of manual pivoting(use a small pen knife or similar) to break up the grease bond. Try that first as I find it odd that it'll be so worn out. If it is worn, I probably have a spare lying around.

I'll probably get these instructions updated whenever I get the time to do that. My methods of cleaning and lubrication have changed a bit

[bychosis]

Thanks QV. It seems to be freely pivoting and is pretty free of grease having been cleaned out back in 2013. Its done plenty of shifting since then and has gradually been getting more difficult to shift. Even with manual pressure it is not engaging with the catch which appears to be visibly worn.

I'm not going to bother with further repairs, the bike will be retired from active duty - and give me a reason to finally get my act together and complete some alternative bikes (Centurion Carbon for one)

[singlespeedscott]

I've tried fixing mine but have had no luck. I think I'll soak them in kero for a few days and see what happens. I'm sure they were working fine when I first got them. How much grease should input on the pawls?

[QuangVuong]

That's one point I want to change. Rather than grease, I have changed to using a liquid lubricant, such as INOX-mx3. You want to allow the spring action to be free as possible, so a thin liquid lubricant will be better than grease. Grease can hinder the spring action particular with more viscous ones.

And you can use as much liquid lubricant as you'd like. Let the excess deep out and it'll be good to go.

[bychosis]

I ended up using rock n roll lube on mine, in hindsight maybe it wasn't thick enough, but everything was still moving freely in the mech.

[singlespeedscott]

Well two days of soaking in kero and a liberal spraying of WD40 seems to have done the trick.

They are now shifting nicely over my deore XT 7 speed cassette

[johnpaul_jones]

HI Guys! I've the same pair of sti levers (the triple version) and the left one is freaking me out.
It works fine but I think there's something broken inside, because when I want to change from the big ring to the middle one, the chain falls straight into the granny ring. Then, I can change to the middle one and so on... but it's an annoying way of shifting.

Anyone with the same issue? Thanks!

[P!N20]

HI Guys! I've the same pair of sti levers (the triple version) and the left one is freaking me out.
It works fine but I think there's something broken inside, because when I want to change from the big ring to the middle one, the chain falls straight into the granny ring. Then, I can change to the middle one and so on... but it's an annoying way of shifting.

Anyone with the same issue? Thanks!

Triples aren't my bag, but it sounds like a cable tension issue as opposed to the lever. Have you tried loosening the cable adjuster a touch?

[johnpaul_jones]

Yes! I also left the bike to my LBS and he founds the lever was working oddly. I don't think he considered the gummed grease issue.
I'm reluctant to disassemble the unit unless it is necessary and I'm afraid that's something broken inside.
If anyone had the same issue please help my wallet!

[Duck!]

Gummy grease is the first suspect, as it basically glues the ratchet pawls into place on their pivots. The pawls only have fine springs, so it doesn't take a lot of gumminess to overpower the springs and stop the pawls dropping into place to make the shift function. It's likely the primary release pawl is working OK, but the secondaries which catch the shifter barrel on the downshift aren't dopping in to pick up the middle stop, so it's just blowing through to the low position.

[johnpaul_jones]

So it could be possibile that it is caused by too much gummy grease?

[Duck!]

Yes. The stuff Shimano used at the time (and possibly still do) is quite prone to drying out and gumming up the mechanism.

It's not implausible that something is actually broken internally, but I'd be laying my suspicion on the grease first.

[MattyK]

Thread dig. Restoring a friend's bike with these exact shifters. Got them loosened up with just WD40 soaking, gears now click through. Gave it a spray with a light lube.

However after recabling it, the RH shifter (big lever) doesn't want to fully return to centre every time. More WD, or time for surgery? Or something else? Tempted to fully submerge in some petrol... (or bin them and buy some Claris R2000 shifters? Would they be compatible?)

[Duck!]

Could be the return spring under the front cover has slipped out of its locating notch (see 4th pic in the first post for the spring in question), causing it to lose tension and prevent the lever returning.

If the shifter ends up beyond salvation, R2000 will be fine, although you may need a new front derailleur to suit the new cable pull.

[MattyK]

That was a thought (having seen RJ the bike guy's video, and my mate telling me he had messed with the front cover previously...) Thanks as usual

[MattyK]

Checked the spring - seemed OK (it pops out as soon as you remove the cover) but made sure it was reset. What I did identify was that tightening down the screw for the faceplate caused it to jam up. Back it off a fraction and it's super smooth.
The washer in there is not missing, and I doubt they've ever been apart before so unlikely that it's lost a part. So I might end up Loctiting that screw and setting it at a functional point.

[MattyK]

Carefully lift whilst twisting the name plate off. You will be greeted with this spring. This is different to the assembly of the new Sora(3300) and 105(5500) levers, but exactly the same as the RX100. Id say its much more easy to dismantle and rebuild because the spring is here.

OMGosh finally got it sorted. Problem was this spring just wasn't seating properly, so every time I'd tighten the screw it would jam the lever to the faceplate. Remove the spring and it was super smooth. After many many attempts it finally went in to position properly (impossible to see because it's all enclosed), and I could tighten the front bolt while the shifter still moved freely. Yay me.