Shimano Saint/XT Lever Piston cross-compatibility

[Staunch]

I've got a set of M820 Saints which are both leaking out of the pistons at the lever end. I'm 99% sure they're not leaking out of the reservoir cap as I've already disassembled these, inspected/cleaned the bladders, and re-assembled (and they're both still clean and dry).

I've seen these el cheapo aftermarker lever pistons on aliexpress, although I can only find these which claim they're for M7000/M8000. Given the lever bodies of these SLX/XT models are very similar to the M820s, I would assume they're the same piston, although I was hoping someone could confirm that?

I've had a look at the exploded schematics for the M820 levers however they don't show the lever piston, or list a part number for it unfortunately.

Would be nice to have some indication on the level of success I would have before I go to effort of trying to repair them. If I don't get any answers, I guess I'll do it anyway and report back sometime in the distant future.

 

[Jpez]

Calling @Labcanary

 

[Labcanary]

Standby, getting photos and my brain in order...

Short answer is yes. But please don't proceed until I show you what not to do!

 

[Labcanary]

Ok.

So I have put an AlieBay piston in this lever. The problem is. I was lazy/dumb and didn't remove a teeny pin holding the plastic free stroke do-hickey before trying to remove the plastic bit. Guess what? Yep, it snapped :facepalm:

Remove the free stroke screw
Remove the rubber cap covering the pivot grub screw
Remove pivot grub screw and push out pivot
The lever blade assembly will drop out.
Push and twist the piston plunger to remove it from the body

Push out the teeny pin pictured below, circled in green. I put the lever body into soft jaws in my vice and used a *ehem* straight pick to tap it out gently. It would be advisable to use something with a flat end and 1mm in diameter instead of what I used!
Now you can remove the plastic thingy without it snapping (Hopefully...)

Access to piston. Push it out from the hose end with a 2mm allen key. Don't lose the spring behind it.

Here is a lever with an intact plastic thingy:

Here is the one with a snapped plastic thingy:

Good luck! Putting it back together is a real fiddle-fart. Much swearing happens in my shed.

 

[Staunch]

Amazing, that's very much appreciated, photos are super helpful as well.

I might buy a cheap pick from bunnings and just file the end down flat until it's the correct diameter if you reckon the spikey end was no good.

 

[ausdb]

Ok.

So I have put an AlieBay piston in this lever. The problem is. I was lazy/dumb and didn't remove a teeny pin holding the plastic free stroke do-hickey before trying to remove the plastic bit. Guess what? Yep, it snapped :facepalm:

<Snipped>

Good luck! Putting it back together is a real fiddle-fart. Much swearing happens in my shed.

Whilst a little late for the valuable threads before Christmas party @Labcanary this has to be one of the best posts on farkin for a long time.
Thank you.

 

[Labcanary]

Amazing, that's very much appreciated, photos are super helpful as well.

I might buy a cheap pick from bunnings and just file the end down flat until it's the correct diameter if you reckon the spikey end was no good.

The spiky end was ok, but those on here with real knowledge and appreciation of good tools might not agree with the use, hehe.

I then used a 2mm flat ended Allen key to tap the pin back in.

Whilst a little late for the valuable threads before Christmas party @Labcanary this has to be one of the best posts on farkin for a long time.
Thank you.

Thanks mate!

 

[bigdamo]

I just did a full service on my fox 36 forks and changed the shim stack and spring. F*** working on MTBs is like entering a very small person world possibly even entering minature world.

Plus all the special obsolete hard to find parts and tools you need. If you drop one of those very very very small parts good luck finding it that's when my swearing comes in.