Repair Tektro HD-M275 brake lever

Question

My girlfriend's son recently acquired a pre-owned Scott Aspect 760 for Christmas (2021 model) - essentially brand-new and ridden once or twice, if at all.

We noticed the other day that something seems to have popped out of the right-hand brake lever:

It seems to me that the circlip holding that "piston" in has popped out - the lever hasn't been struck as far as we can tell, there's no damage to the lever whatsover.

I believe the brake system is the Tektro HD-M275, and the Googling I've done so far suggests that this "piston" is the "reach pin", but I can't find any info on how serviceable this is:

(the picture I found with the reach pin listed was for Auriga levers, items 3/4/5):

There's some slight fluid weepage, so a refill and bleed is presumably a certainty?

Our options at the moment are:

1. Attempt to refit the existing reach pin and circlip, bleed the system and see how it goes.
2. Buy a new lever, refill and bleed the system.
3. Book it into LBS and let them deal with it (they don't have any availability for several weeks though).

I don't want to waste any time with option 1 if it's unlikely to be successful, likewise it would be a shame to spend time and money on option 2 if it's fixable.

Does anyone have any knowledge of the operation and servicing of these levers?

NB. The bike is still under warranty - if this is a manufacturing fault with the brake lever, I can chase up with the store (not my LBS) where it was originally purchased.

Answer 1

Most levers come with some lubrication at the ball tip of the plunger (aka reach screw), so hopefully some of that escaping is all you're seeing to suggest you've lost fluid. When the snapring pops out like like this it's usually nothing to do with bleeding, so if you have lost fluid it's not clear why.

If you have all the parts I would try just putting it together first. If the circlip has been warped, it needs to be bent back into shape or replaced so it can do its thing. (If it's really messed up replacement is much better).

If you have the right kind of long, skinny, small snapring pliers then it's a trivial thing to put the lever back together. If you don't then it's not.

Getting the snapring in tends to be much easier if you have one of the lever pivots disconnected. That way the lever is out of the way while you're doing it. I believe you'll find that on this lever compared to the Auriga in the diagram, there are no set screws securing the pivot axles, which means they will be some kind of press fit compared to a simple slip fit like on the kinds that have set screws, and if that's true will need to be punched out with some force. So if I'm right that means you have the choice of doing one of those two inconvenient things.

Edit: Just to confirm, I tried unthreading the reach adjust all the way while the pivots are still attached on one of these levers at work today, and it doesn't work. That means the lever blade will be right smack in the way as you do your surgery unless you push out one of the pivot axle (presumably the one not covered by the plastic shield thing on top).