Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Mountain Biking Mountain biking is one of the fastest growing sports in the world. Check out this forum to discuss the latest tips, tricks, gear and equipment in the world of mountain biking.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 08-19-08, 04:27 PM   #1
patentcad
Peloton Dog
Thread Starter
 
patentcad's Avatar
 
Join Date: Nov 2005
Location: Chester, NY
Bikes: 2013 Scott Foil, 2014 Scott Addict, 2008 Cervelo P3 (TT), 2015 Scott Scale 700SL MTB
Posts: 59,454
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 60 Post(s)
Hydraulic disc brakes- air in the lines?

I go to my MTB the other day. It has Avid Ultimate disc brakes. I squeeze the levers, they offer little resistance, go right to the handlebars, so that doesn't feel right. But the brakes are working. Then after a couple of minutes, they feel more normal. Noticed that on today's ride too, the brakes seemed odd the first couple of minutes, quickly returned to normal.

I describe this to my LBS, the instant response is 'air in the hydraulics, you have to bleed the air out of the system'. I ask him if this is tricky, he says 'a little', which essentially means that for me it would be like building a fusion reactor out of balsa wood, I'll bring it to them. He says that while the brakes work OK now, this condition does worsen with time.

Comments?
patentcad is offline   Reply With Quote
Old 08-19-08, 04:51 PM   #2
cryptid01
one less horse
 
cryptid01's Avatar
 
Join Date: Aug 2003
Location: East Jesus NY
Bikes: are better than yours
Posts: 5,600
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Had your bike been hanging or upside down for a while prior to this?
cryptid01 is offline   Reply With Quote
Old 08-19-08, 10:09 PM   #3
taylor p
Senior Member
 
taylor p's Avatar
 
Join Date: Jul 2006
Location: Brainerd MN
Bikes:
Posts: 999
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
After a couple of minutes of using the brakes?
I would try bleeding the brakes
taylor p is offline   Reply With Quote
Old 08-19-08, 11:04 PM   #4
jcook1989
Senior Member
 
Join Date: Aug 2008
Location: San Luis Obispo/San Diego
Bikes: Norco Rampage
Posts: 223
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by gastro View Post
Had your bike been hanging or upside down for a while prior to this?
Mine will go soft for a little bit when I have it upside down. I have to give it a few pulls to get it working good again. I don't think its from air in the lines because I have recently bleed both brakes but I'm not sure.
jcook1989 is offline   Reply With Quote
Old 08-20-08, 05:00 AM   #5
rankin116
Senior Member
 
rankin116's Avatar
 
Join Date: Jun 2007
Location: ChapelBorro NC
Bikes:
Posts: 3,988
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 33 Post(s)
Quote:
Originally Posted by jcook1989 View Post
Mine will go soft for a little bit when I have it upside down. I have to give it a few pulls to get it working good again.
rankin116 is offline   Reply With Quote
Old 08-20-08, 05:45 AM   #6
RT
The Weird Beard
 
RT's Avatar
 
Join Date: May 2005
Location: COS
Bikes:
Posts: 8,554
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Go mechanical.
RT is offline   Reply With Quote
Old 08-20-08, 09:24 AM   #7
foresthill 
Senior Member
 
Join Date: Aug 2005
Location: Lafayette, CO
Bikes: MTB: Stumpjumper FSR, Road: De Rosa King 3
Posts: 1,212
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Bleeding your brakes, while a little time-consuming the first time you do it, is really not all that hard. The bleed kit comes with pretty detailed instructions. The first time worked out great for me. Save yourself the ~$25/brake and do it yourself. (You will need a workstand for this.)
__________________
2009 De Rosa King 3: Red Shifters, RD, Cranks, Brakes, BB, & Cassette; Force FD; Reynolds DV46c wheels.

2004 Specialized Stumpjumper FSR: X.0 gripshifters, RD; XTR FD, Cranks, Hayes HFX Carbon 9 Brakes; AC 350 Disc Wheels; Manitou Minute 2:00 100mm fork; Fox propedal triad rear shock; WTB weirwolf UST w/Stan's tubeless system.
foresthill is offline   Reply With Quote
Old 08-22-08, 07:36 AM   #8
mic2377
Senior Member
 
Join Date: May 2007
Bikes:
Posts: 207
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Bleeding is easy if you brakes already have fluid in them. Don't hang upside down, this is generally bad for all bikes containing fluids (ie suspension forks, hydraulic brakes, etc). I had my headshok leak oil after this.

Just get the bleed kit and do this yourself. A workstand is not necessary. Also, follow the instructions. Make sure to keep the reservoir full as you do it, if you suck some air in.... you get to do it all over again!

Be glad you are not trying to bleed a new pair of Shimano hydros. That is a pain. I must have run 25 fills of the reservoir through it and pumped the brake lever for 30 min before they bled properly.

Oh, hydros are that much better than mechanicals. I rode mechanicals for a year prior to hydros, and they are the best thing since sliced bread.

And for god's sake, use the right fluid! I believe Avids are DOT fluid, but don't quote me on this.
mic2377 is offline   Reply With Quote
Old 08-22-08, 09:23 AM   #9
jcook1989
Senior Member
 
Join Date: Aug 2008
Location: San Luis Obispo/San Diego
Bikes: Norco Rampage
Posts: 223
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Yeah Avid are DOT. You need to get the Avid bleed kit because if the special fittings on the brakes. The kit is pretty sick though super easy and it comes with fluid.
jcook1989 is offline   Reply With Quote
Old 08-22-08, 02:32 PM   #10
Mr. Underbridge
Senior Member
 
Join Date: Mar 2007
Location: Reston, VA
Bikes: 2003 Giant OCR2
Posts: 2,369
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
How does one know when the problem is air in the lines? I have hydros (Hayes Stoker Trail) and the left one (which I use nearly exclusively) is getting soft. Bike's pretty new, only a few hundred miles on it. I did have it upside down once to change a tire (before I knew that doing that was a no-no).

What does air in the lines feel like vs. pad wear?
Mr. Underbridge is offline   Reply With Quote
Old 08-22-08, 02:44 PM   #11
ca7erham
****** (can I say this?)
 
Join Date: Jun 2008
Location: CO
Bikes:
Posts: 1,900
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by rankin116 View Post
I second that. . .
ca7erham is offline   Reply With Quote
Old 08-22-08, 07:32 PM   #12
DirtPedalerB
unofficial roadie
 
DirtPedalerB's Avatar
 
Join Date: Jul 2006
Location: Out in the woods you see
Bikes: 2004 Marin bobcat trail, 2006 trek fuel ex7, 2007 iron horse road bike
Posts: 1,440
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I flip my bike over all the time with hydros and have no problems... also I believe fliping it over for the fork fluid to lube the seals occasionally is recommended.. how else are you going to change a tire on the trail besides flipping the thing over... I guess don't store it upside down, but leaving it inverted for less than an hour isn't going to hurt anything.
DirtPedalerB is offline   Reply With Quote
Old 08-22-08, 08:36 PM   #13
Scratcher33
Senior Member
 
Join Date: Jun 2008
Location: Eugene, OR
Bikes: Jamis XLT 2.0, Kona Fire Mountain
Posts: 564
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Mr. Underbridge View Post
I did have it upside down once to change a tire (before I knew that doing that was a no-no).
Why is that a no-no?
Scratcher33 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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



All times are GMT -6. The time now is 03:25 PM.