Deore Brake Question

[Cole]

I just bought a bleed kit because I was pulling to the bar and not locking up. When I first got the bike last year they worked great, I adjusted the lever close to bar and since then they seem spongy. Before bleeding tonight I adjusted the levers back out as far as they go and now they seem to work great. Can easily get the rear off the ground at low speeds and little pressure.

Any idea? Do I need to bleed, or is there there just an issue with the adjustment

 

[Glenn Rides After 4 PM CST]

I just bought a bleed kit because I was pulling to the bar and not locking up. When I first got the bike last year they worked great, I adjusted the lever close to bar and since then they seem spongy. Before bleeding tonight I adjusted the levers back out as far as they go and now they seem to work great. Can easily get the rear off the ground at low speeds and little pressure.

Any idea? Do I need to bleed, or is there there just an issue with the adjustment

I would bleed them. There's probably air in the lever.

 

[Cole]

I would bleed them. There's probably air in the lever.

Will do, thanks.

 

[tonyride]

Definitely bleed.

 

[Juggernaut]

I just bought a bleed kit because I was pulling to the bar and not locking up. When I first got the bike last year they worked great, I adjusted the lever close to bar and since then they seem spongy. Before bleeding tonight I adjusted the levers back out as far as they go and now they seem to work great. Can easily get the rear off the ground at low speeds and little pressure.

Any idea? Do I need to bleed, or is there there just an issue with the adjustment

you can probably get away with just a lever bleed. I would take a peek at the pads while you’re at it, just to check wear.

 

[Karate Monkey]

What specific brakes (number engraved/printed on the brake lever body)? The servo-wave design [there's a cam track in the lever blade/rollers] gets hinky when you dial it all the way in. There are non-servo wave, non-series Deore levers, which is why I ask.

 

[Cole]

What specific brakes (number engraved/printed on the brake lever body)? The servo-wave design [there's a cam track in the lever blade/rollers] gets hinky when you dial it all the way in. There are non-servo wave, non-series Deore levers, which is why I ask.

Bl-m6100

 

[Cole]

you can probably get away with just a lever bleed. I would take a peek at the pads while you’re at it, just to check wear.

Pads are fine. The bike isnt a year old yet, and I don't right that much.

 

[Karate Monkey]

Bl-m6100

Yeah, they will get 'squishy' if you run the reach all the way in. Consequence of the design (must run through the whole track with minimal movement). IME, there's a little bit of 'squish' when you get the initial rotor contact, followed by hard stop; if you dial the reach in all the way, it can feel like they're just going straight to the bar.

That said, bleeding is a good idea. 99% of Shimano's brakes are installed using a j-kit (press the sealed line into a corresponding lever), so there's always the possibility that there is the less-than-full amount of fluid in the brake. Don't do it with the pads installed--use a bleed block. Used pads+pad spacer will result in over-filling, usually followed by bursting the lever seals when you go to reset the pistons/install new pads.

 

[Cole]

Yeah, they will get 'squishy' if you run the reach all the way in. Consequence of the design (must run through the whole track with minimal movement). IME, there's a little bit of 'squish' when you get the initial rotor contact, followed by hard stop; if you dial the reach in all the way, it can feel like they're just going straight to the bar.

That said, bleeding is a good idea. 99% of Shimano's brakes are installed using a j-kit (press the sealed line into a corresponding lever), so there's always the possibility that there is the less-than-full amount of fluid in the brake. Don't do it with the pads installed--use a bleed block. Used pads+pad spacer will result in over-filling, usually followed by bursting the lever seals when you go to reset the pistons/install new pads.

So even if not doing a full bleed, use the block?

 

[qclabrat]

So even if not doing a full bleed, use the block?

Good idea to avoid getting oil on pads. Simple task which will save you a headache later

 

[Karate Monkey]

So even if not doing a full bleed, use the block?

Yeah. Two reasons, like @qclabrat said. One is practical: keep the pads away from oil.

Two requires some obtuse thinking: The system is expecting to have a certain amount of oil in it, and the seals are designed around that. Most of the horror stories that you hear about Shimano brakes leaking from the master cylinder are from the pressure relief valve (one time use thinner section of the bladder) doing exactly what it's supposed to do: relieve pressure. In a well-bled brake, there is minimal expansion room left in the modern Shimano design...so someone who bleeds the brake with a spacer/worn pads allows the pistons to be advanced more than necessary, and the system gets over-filled. When the pistons get reset later on after the pads are worn out, the excess fluid has nowhere to go, so the relief blows out, and your brake is ruined.

SOP for Shimano's manual is to attach a bleed cup to the lever before resetting, just in case the above happened, the excess fluid just gets pushed out.

 

[Dave Taylor]

I would do a full bleed if it's been a year. I have been using Motul dot 5.1 in my xt brakes and sram force brakes. Really like it. It's so simple to bleed them now you might as well do it once or twice a year.

 

[Cole]

Thanks, i

I would do a full bleed if it's been a year. I have been using Motul dot 5.1 in my xt brakes and sram force brakes. Really like it. It's so simple to bleed them now you might as well do it once or twice a year.

Thanks, I did a lever bleed. And I still don't get a hard bite once I adjust them closer to the bar.... Maybe next weekend. Or I'll tell my wife they are unsafe and need to upgrade 👍

 

[serviceguy]

I have been using Motul dot 5.1 in my xt brakes

 

[John the Plumber]

I thought you have to use mineral oil on shimano xt brakes and dot on sram. Check it out.........

 

[tonyride]

I thought you have to use mineral oil on shimano xt brakes and dot on sram. Check it out.........

SRAM DB8 brakes use mineral oil but I'm pretty sure that Shimano XT uses it too, not DOT brake fluid.

 

[Dave Taylor]

I would do a full bleed if it's been a year. I have been using Motul dot 5.1 in my xt brakes and sram force brakes. Really like it. It's so simple to bleed them now you might as well do it once or twice a year.

Correction. I use it the Motul dot 5.1 in my sram road and mt brakes. My Shimano bleed kit came with the red mineral oil. My bad.