Bleeding brakes in reverse
#1
Junior Member
Thread Starter
Bleeding brakes in reverse
I bought a Niner RTL frame the other day and I was transferring over all my parts form my previous Gravel bike. I have a Tiagra 2x10 groupset that came with those quick connect hydraulic brake hoses. I needed to route my cables and hoses through the dropbars and then through the downtube so I bought new hydraulic hoses. The front went well, bleeding brakes for (my) first time was easy. When I got to the back caliper, I bleed them as I should have but they were very spongy, and would not stop me at all. Tried again, and again, and again, about 12 or 13 times before I finally realized that it was not gonna work. I even put the bike straight up and let the caliper hang, no luck. So, on a whim, I decided to fill the cup on the reservoir (atop the shifter) and then pull it through the caliper in reverse order with the syringe. Low and behold as soon as I started, huge bubbles came through that were lodged in the caliper. Brakes are good and a new way (for me) to do it worked well. Cheers.
Likes For Breadfan:
#3
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 39,036
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 141 Post(s)
Tagged: 1 Thread(s)
Quoted: 5957 Post(s)
Liked 2,868 Times
in
1,598 Posts
People often forget an important step for effective bleeding.
We all know that bubbles rise, so orientation of the parts accordingly matters. But people forget that bubbles can cling to walls.
Pour yourself a coke or champagne, and you'll see the bubbles rising, except for those clinging to the glass. Those won't move until you tap the glass to loosen them.
Nurses tap IV lines to clear bubbles and you need to do likewise to encourage air to work its way to the bleed port.
As the OP found air can also get trapped in the caliper, so orient it so the line is on top and tap intermittently for a minute or two.
BTW - brake fluid is fairly viscous, so you need to be patient and give bubbles enough time to work their way to the door.
We all know that bubbles rise, so orientation of the parts accordingly matters. But people forget that bubbles can cling to walls.
Pour yourself a coke or champagne, and you'll see the bubbles rising, except for those clinging to the glass. Those won't move until you tap the glass to loosen them.
Nurses tap IV lines to clear bubbles and you need to do likewise to encourage air to work its way to the bleed port.
As the OP found air can also get trapped in the caliper, so orient it so the line is on top and tap intermittently for a minute or two.
BTW - brake fluid is fairly viscous, so you need to be patient and give bubbles enough time to work their way to the door.
Last edited by FBinNY; 10-24-23 at 07:56 PM.
Likes For FBinNY:
#4
Method to My Madness
Join Date: Nov 2020
Location: Orange County, California
Posts: 3,859
Bikes: Trek FX 2, Cannondale Synapse x2, Cannondale CAAD4, Santa Cruz Stigmata 3
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 2063 Post(s)
Liked 1,557 Times
in
1,078 Posts
I have not yet had to bleed my brakes, but what you did sounds like the procedure to bleed brakes on a car. When the "huge bubbles came through", did you see those huge bubbles in the syringe or in the cup?
Last edited by SoSmellyAir; 10-22-23 at 06:33 PM.
Likes For choddo:
#6
Junior Member
Thread Starter
Likes For Breadfan:
#7
Senior Member
Join Date: May 2022
Location: USA - Southwest PA
Posts: 3,239
Bikes: Cannondale - Gary Fisher - Giant - Litespeed - Schwinn Paramount - Schwinn (lugged steel) - Trek OCLV
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1451 Post(s)
Liked 2,048 Times
in
1,157 Posts
also had a heckuva time bleeding Tiagra brakes on one of my bikes
finally coaxed remaining bubbles in similar way
related note - at one point questioned and almost regretted going with the Tiagra 10 spd shifters / brakes (they were takeoffs) - but after months of use they operate very well … one of my best shifting bikes - and the brakes are also great and now close to power of my XT equipped bikes … only minor issue is the front shifting from 31 to 48t big ring is a tad slow / clunky (paired with GRX front derailleur)
finally coaxed remaining bubbles in similar way
related note - at one point questioned and almost regretted going with the Tiagra 10 spd shifters / brakes (they were takeoffs) - but after months of use they operate very well … one of my best shifting bikes - and the brakes are also great and now close to power of my XT equipped bikes … only minor issue is the front shifting from 31 to 48t big ring is a tad slow / clunky (paired with GRX front derailleur)
#8
Method to My Madness
Join Date: Nov 2020
Location: Orange County, California
Posts: 3,859
Bikes: Trek FX 2, Cannondale Synapse x2, Cannondale CAAD4, Santa Cruz Stigmata 3
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 2063 Post(s)
Liked 1,557 Times
in
1,078 Posts
Not having bled bike brakes before, so not sure what the "regular" way entails, but what you did sounds like the way to go to eliminate any air trapped in the brake caliper, rather than hope to dislodge the air pocket and cause it rise up all the way through the brake hose and the STI lever.
#9
Junior Member
Thread Starter
also had a heckuva time bleeding Tiagra brakes on one of my bikes
finally coaxed remaining bubbles in similar way
related note - at one point questioned and almost regretted going with the Tiagra 10 spd shifters / brakes (they were takeoffs) - but after months of use they operate very well … one of my best shifting bikes - and the brakes are also great and now close to power of my XT equipped bikes … only minor issue is the front shifting from 31 to 48t big ring is a tad slow / clunky (paired with GRX front derailleur)
finally coaxed remaining bubbles in similar way
related note - at one point questioned and almost regretted going with the Tiagra 10 spd shifters / brakes (they were takeoffs) - but after months of use they operate very well … one of my best shifting bikes - and the brakes are also great and now close to power of my XT equipped bikes … only minor issue is the front shifting from 31 to 48t big ring is a tad slow / clunky (paired with GRX front derailleur)
#10
Junior Member
Thread Starter
Not having bled bike brakes before, so not sure what the "regular" way entails, but what you did sounds like the way to go to eliminate any air trapped in the brake caliper, rather than hope to dislodge the air pocket and cause it rise up all the way through the brake hose and the STI lever.
#11
Senior Member
Join Date: Sep 2009
Posts: 1,975
Bikes: Habanero Titanium Team Nuevo
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 401 Post(s)
Liked 187 Times
in
123 Posts
There is more than one way to bleed brakes. You can do a complete gravity bleed overnight and just let everything run downhill. Then a bit of on/off with the bleed valve in the caliper, and generally you are good to go. However, I have noticed a bit of tweaking is needed at times. To get my own r7000 to actually grab before the brake got too close to the drop bar, I had to do a trick. This is not recommended but works. If you find your brakes are not spongy but they go almost to the bar before you stop then the free stroke needs adjusting. You cannot do this on the 105. I saw a tip on youtube that worked great. I actually left the bleed port screw in the shifter and then push a little bit of fluid up into the brake line. You have to be careful and go only a little but and very slow. Otherwise you can break the bladder that is up in the shifter. Doing this will give you crisper action however you have to watch disk rub and too much and you will lock the brake. If that happens just let a little out the bleed value again.
Likes For deacon mark:
#12
ignominious poltroon
Join Date: Jan 2022
Posts: 4,173
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 2296 Post(s)
Liked 3,529 Times
in
1,855 Posts
A syringe is a tried and true method for de-gassing a fluid. I sometimes put one at each end.