Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Deore Hydro discs, Intermittent performance

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Deore Hydro discs, Intermittent performance

Old 11-26-18, 11:44 AM
  #1  
TheReal Houdini
Senior Member
Thread Starter
 
Join Date: Apr 2011
Location: Vienna, VA
Posts: 221

Bikes: Cervelo P3 (retired), Habanero Road, Novara Safari, Batavus Personal Delivery Bike

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Deore Hydro discs, Intermittent performance

I installed Shimano Deore Hydraulic Disc brakes a couple of years ago and have enjoyed excellent all-weather performance, commuting year round in the mid-Atlantic since then. Then, over the course of a 45 minute commute, the rear leaver softened, and went completely limp - leaver in contact with the bar, minimal friction at the pad. It stayed that way for one 45 minute commute. I parked the bike for a week, ate some turkey, and hopped back on for the ride to work this morning. The brake started the way I left it - no friction when flat to the bar. At that point, I figured I must have sprung a leak. Then, over the course of the ride, performance got gradually better, and ended up fully restored by the time I got to work. One potential factor: conditions were just above freezing and raining when the brake didn't work. No problems with colder or wetter weather, but I typically have avoided that particular combination in the past.


Therefore, I hypothesize the copious consumption of turkey fixes hydraulic fluid leaks.


If you'll spare me a lecture on causation vs. correlation, proffer a more scientific analysis, and suggest remedies the fault, I would be grateful.


Thanks in advance!
TheReal Houdini is offline  
Old 11-26-18, 11:49 AM
  #2  
LesterOfPuppets
cowboy, steel horse, etc
 
LesterOfPuppets's Avatar
 
Join Date: Sep 2008
Location: Valley of the Sun.
Posts: 37,147

Bikes: everywhere

Mentioned: 60 Post(s)
Tagged: 1 Thread(s)
Quoted: 7418 Post(s)
Liked 2,638 Times in 1,424 Posts
Had the bike ever been placed vertically or inverted?
LesterOfPuppets is online now  
Old 11-26-18, 11:54 AM
  #3  
*Scuba 
Made in Taiwan
 
Join Date: Sep 2008
Location: Vancouver
Posts: 193

Bikes: Camerotti ti roadbike, Old Sears Free Spirit Tange Hi-Ten Single Speed built from a 12 speed, 1997 Cannondale CAD3 r500 with Shimano 6400 groupset

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Liked 4 Times in 4 Posts
When you say a couple of years ago that you got your brake set up, have they ever been bled and maintained at all? Mineral oil systems like the Shimano hydraulic brakes need a little more maintaining and don't take containment as well as DOT fluid brakes.

If this is your yearly commuter bike, I would recommend at least a bled annually, but preferably every 6 months. What are the condition of your rotors and your pads?

What you are describing sounds like water in the system, moisture can get into hoses and hydraulic brake systems.
__________________
All dogs want to be lap dogs doesn't matter the size
-Animal loving friend
*Scuba is offline  
Old 11-26-18, 12:28 PM
  #4  
TheReal Houdini
Senior Member
Thread Starter
 
Join Date: Apr 2011
Location: Vienna, VA
Posts: 221

Bikes: Cervelo P3 (retired), Habanero Road, Novara Safari, Batavus Personal Delivery Bike

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Re: vertically or inverted - I vaguely remember hanging it briefly while I changed a tube. It wouldn't have been vertical, but it would have elevated the caliper relative the to the leaver - it wouldn't have been the first time thou...

I set them up originally in accordance with Shimano's installation instructions, and changed the pads sometime this Spring. Pads and rotors are in good shape. I've not bled them since set-up.
TheReal Houdini is offline  
Old 11-26-18, 12:39 PM
  #5  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,599

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,320 Times in 830 Posts
Bladder in the master, is supposed to keep the air out
but allow expansion space for the heated fluid....

I only recently fitted TRP Hydraulic Hy Rd Calipers ..


Shimano has better documentation, online .. to find..

MTB forums to search..





...
fietsbob is offline  
Old 11-26-18, 01:05 PM
  #6  
JonathanGennick 
Senior Member
 
JonathanGennick's Avatar
 
Join Date: Apr 2007
Location: Munising, Michigan, USA
Posts: 4,131

Bikes: Priority 600, Priority Continuum, Devinci Dexter

Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 685 Post(s)
Likes: 0
Liked 55 Times in 37 Posts
Originally Posted by TheReal Houdini View Post
Re: vertically or inverted - I vaguely remember hanging it briefly while I changed a tube. It wouldn't have been vertical, but it would have elevated the caliper relative the to the leaver - it wouldn't have been the first time thou...
I've had bikes that, when I've hung them by their rear wheel, would need a few levers pumps before the brakes worked again.

The right thing is to bleed the system. In a lazy moment, I might say "good enough" and run the brakes until the behavior returned and became annoying, and _then_ bleed the system.

Shimano brakes are some of the easiest to bleed, fwiw.
JonathanGennick is offline  
Old 11-26-18, 01:35 PM
  #7  
GrainBrain
Senior Member
 
GrainBrain's Avatar
 
Join Date: Aug 2017
Location: Central Io-way
Posts: 2,041

Bikes: LeMond Zurich, Giant Talon 29er

Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1051 Post(s)
Liked 334 Times in 252 Posts
Originally Posted by JonathanGennick View Post
I've had bikes that, when I've hung them by their rear wheel, would need a few levers pumps before the brakes worked again.
+1

I run older Deore hydros, in all kinds of weather. Often in winter way past freezing. They are ridiculously trouble free, for me. Never maintenanced the fluid, not in 5 years.

Though everytime I invert the bike, the rear will go soft, and I'll need to pump a few times, then no problems.

I'd agree with bleeding the system, can't hurt. Don't get fluid on the pads!! Maybe check to make sure the fittings are tight. You could've had some moisture creep in.
GrainBrain is offline  
Old 11-28-18, 02:39 PM
  #8  
RubeRad
Keepin it Wheel
 
RubeRad's Avatar
 
Join Date: Aug 2011
Location: San Diego
Posts: 9,452

Bikes: Surly CrossCheck, Krampus

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Liked 1,297 Times in 968 Posts
I think you might be able to get away with 'burping' rather than a full bleed. Check out this video:


I messed with my shimano hydros and made the front brake so soft I could hold the lever on the handlebar and still roll down a hill. I bought this cheap bleed kit (note brake fluid not included, I already had some mineral oil for bike brakes), and the burping with the funnel totally worked. And I have a bonus syringe and clamping hose in case I ever need a full bleed.
RubeRad is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Trellaine
Commuting
54
02-13-19 03:18 PM
uRabbit
Bicycle Mechanics
15
02-20-17 03:18 PM
El Cid
Bicycle Mechanics
2
12-05-13 11:18 AM
j3ns
Bicycle Mechanics
8
08-15-13 09:21 AM
jsdavis
Hybrid Bicycles
19
02-23-12 01:50 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.