The Shimano SLX brakes on my Trigger have been great, no problems at all. But on the last run at BPW yesterday the rear brake gave a couple of soft pulls then could be pulled back to the lever with no resistance at all.

First thought – maybe overheated? Nope, disc and caliper were warm but not super hot. The pads are the finned ones too so they hardly ever get really hot.
Leaking? Nope, can’t see any fluid leaking out anywhere.
Pads are getting a little low but still a fair bit of material on there. I see them move a little when I pull the lever, but not enough to do more than lightly touch the disc.

Seal blown somewhere? Are they serviceable?

If you can’t see any fluid leaking from around the caliper pistons or hoses then it’ll be the seals in the lever. Known problem and seems to almost always be the rear one that pops.

No spares I’m afraid- time for a new brake :-/

Actually a quick Google search suggests you can buy the levers separately but nowhere seems to have them in stock and it’s not that much more to buy a whole new brake with pads.

If you find a separate lever don’t forget you’ll need a new olive to reconnect the hose

If the piston seal has split then usually you get no travel at caliper end and leaking fluid. I have fixed quite a few shimano levers by removing the lever and piston and giving the metal surfaces a clean and rub down with very fine wet and dry paper.

The piston can get stuck in the bore and then does not retract fully when the lever returns. This creates very short piston throw (at caliper end) and virtually no power.

Nothing to lose by taking the lever off and cleaning the piston. Very easy to do.

When the lever seal went on mine it was obvious, it had about 50% of the throw it had before and if anything it binded on rather than go soft.

I’ve found that era of Shimano won’t take pads to the metal. My first port of call would be fresh pads.

Typical shimano brake problem , give them a bleed and you should get
them back working again, maybe a set of pads as well.

Nope it’s gone, time to buy a new lever. All Shimano levers do it if you work them hard. They are utter suite, it still amazes me that they get so much love on the googleweb

Thanks – will take apart just for my curiosity and if I can get it fixed, bonus. Think I have an old Deore one I can put on there for a bit.

All the cheap M675 brakes seem to have gone now, then start looking at pairs, then at the sub-£300 1×11 SLX groupset on Merlin that would get me brakes as well as a new rear mech, cassette, shifter, chainset… 😕