eduaqa

My bike Trek 8000 has Shimano M585 hydraulic disk brake, and a have following situation:
The front brake the lever just travel a few mm before lock the will, I would say less than 1/4 of total distance between the lever released and the handle bar.
The rear brake the lever travel seems good and it travel about 1/2 of the distance between the lever released and the handle bar.
This start happening after a remove the front rim, pushed the piston all the way to the caliper and put the pad and the rim back
Initially there was not brake, than the piston self adjusted, but, seems that they adjusted to close to the disk because even the rim is not running freely, if I handle the bike over the ground and spin the rim it stop after 3-4 turns
I already centered the caliper, releasing the screws and braking and tight the screw back while holding the brake.
What can be happening?

jimc101

Did any fluid come out of the reservoir?

They are old (that design/model is pushing 10+ years now), have they ever been bleed?

Would first look at bleeding the brakes (this is a more involved process than the latest Shimano brakes, would look at the cost of tools needed vs replacing the brakes/ getting new levers (all Shimano hydraulic brakes are interchangeable, I have a set of M585 calipers with M675 levers, they work fine, and are easier to bleed than M585 levers)), this will effectively reset them to the factory setting. Also, when you say 'not brake' are the pads/rotors clean i.e not contaminated with brake fluid?

eduaqa

No fluid out of reservoir
no sure about bleed, I bought the bike used recently
when I said initially no brake, I think was because as the piston was totally inside the caliper it was necessary compress the lever to the end of the travel (until touch the handle bar) a few times for the piston auto adjust itself
after that its breaking ok, but seems its not return as much it should because seems like the wheel is been "hold" because when I spin the wheel it just turn 3-4 times and stop
i will check about the interchange levers. This levers are those that have the gear on the brake lever to go hi. To return gear they have separated lever

jimc101

Do you know the history of the bike? Just open up the reservoir top, and lift the rubber cover (Diaphragm) The fluid should be near the top and a clear red color, if the fluid is low, add more ( be careful not to add air into the system) if the color is not clear red (i.e. dark dirty red or any other color), all the fluid need flushing (bleeding) and replacing with fresh fluid.


Guessing you have ST-M585 DCL's not BR-M585

You can ID exactly what you have either by looking at the link below, or the exact part number will be cast into the underside of the brake/shifter you have

https://si.shimano.com/#/en/search/Keyword?name=585

eduaqa

You are right about the model, the caliper is BR585 and the lever is ST585. I didn't know that they used different letter for the caliper and the lever. Thanks for link and help me learn that.
i don't know the history, and I will check the oil level and the color and add information here.
also I will try to push the piston back to be sure that is really the brake pad that is not allowing the wheel spin freely.