No Front Brake Pressure
08-29-2011, 06:23 PM
#1
Senior Member
SuperBike
Thread Starter
Join Date: May 2007
Location: Austin, Texas
Posts: 1,283
No Front Brake Pressure
So, I've bled the front brakes 3 different times, using a couple different methods and still have what feels like air in the lines.
Every time I bleed them there are no air bubbles coming out of the bleeder valve and the lever gets firm (but never firm enough). The next time I go out to the bike a couple days later, it's lost the pressure.
It's got new pads, and I did a full fluid flush to clear out the lines. I don't have any visible leaks.
I searched and found that pressing the caliper back in fully can help in case there's air inside the caliper itself. Does that sound like a possible solution to my issue?
I've been having to bleed them alone, by hand, which is obviously not the easiest thing to do.
I bought a set of solo bleeders, but haven't installed them yet. Trying to figure out if using the solo bleeders or pressing the caliper in should be the first step... I'd rather not do both at the same time to limit the area of effect.
.... the rear brakes are fine.
Sorry for the long post, but I figured as much background info as possible would be useful.... cause I wanna ride damnit!
Every time I bleed them there are no air bubbles coming out of the bleeder valve and the lever gets firm (but never firm enough). The next time I go out to the bike a couple days later, it's lost the pressure.
It's got new pads, and I did a full fluid flush to clear out the lines. I don't have any visible leaks.
I searched and found that pressing the caliper back in fully can help in case there's air inside the caliper itself. Does that sound like a possible solution to my issue?
I've been having to bleed them alone, by hand, which is obviously not the easiest thing to do.
I bought a set of solo bleeders, but haven't installed them yet. Trying to figure out if using the solo bleeders or pressing the caliper in should be the first step... I'd rather not do both at the same time to limit the area of effect.
.... the rear brakes are fine.
Sorry for the long post, but I figured as much background info as possible would be useful.... cause I wanna ride damnit!
08-29-2011, 07:34 PM
#2
Senior Member
MotoGP
Join Date: Jul 2007
Location: NYC
Posts: 5,033
Yeah brakes can be frustrating. Have you tried bleeding at the banjo bolt at the lever? I have found thats the only way to get all the air out on the clutch too even with a mityvac bleeder.
Just wrap a rag around the banjo, pump & hold the lever, crack the banjo bolt loose enuff to expel air and a bit of fluid, and tighten the bolt while you are still holding the lever. Presto, problem gone.
Just wrap a rag around the banjo, pump & hold the lever, crack the banjo bolt loose enuff to expel air and a bit of fluid, and tighten the bolt while you are still holding the lever. Presto, problem gone.
08-29-2011, 07:57 PM
#3
Senior Member
Superstock
Join Date: Jan 2011
Location: Santa Clara, CA
Posts: 258
What condition are your lines in?
Are they stainless or stock?
And as well, what are you using to connect over the brake bleeder?
Even with the mitivac mentioned above, I've always found I get little air bubbles from the threads. I know that speedbleeders carry a thread sealant that works well, but I typically just use top grade silicone tape and it works just fine after that.
And as well, are you getting any fluid loss anywhere? Pull the plunger cover forward on the piston at the MC, if there's anything at all behind it, you just need a new piston. Other places to check are the connection between the cup and M/C.
Are they stainless or stock?
And as well, what are you using to connect over the brake bleeder?
Even with the mitivac mentioned above, I've always found I get little air bubbles from the threads. I know that speedbleeders carry a thread sealant that works well, but I typically just use top grade silicone tape and it works just fine after that.
And as well, are you getting any fluid loss anywhere? Pull the plunger cover forward on the piston at the MC, if there's anything at all behind it, you just need a new piston. Other places to check are the connection between the cup and M/C.
08-30-2011, 08:29 AM
#5
Senior Member
MotoGP
Join Date: Mar 2007
Location: Phoenix, AZ
Posts: 3,132
You can also try: ziptie the lever shut overnight and turn the bars so that the master cyl reservoir is at the highest point in the system.. Sometimes that allows the air to work it's way up and out of the system.
08-30-2011, 10:36 AM
#6
Senior Member
SuperSport
Join Date: Jun 2008
Location: San Diego
Posts: 916
I may be wrong but if you bled the system and it felt good then the next day it's bad are you sure all the crush washers were good? Easy check wipe with a clean paper towel. Or maybe the MC piston is bleeding by?
Banjo bolts installed to torque spec?
What changed from before when they were good till now.
Also before you press in the calipers hose them down with break cleaner to remove contaminants that may damage the seals.
Banjo bolts installed to torque spec?
What changed from before when they were good till now.
Also before you press in the calipers hose them down with break cleaner to remove contaminants that may damage the seals.
08-31-2011, 06:34 AM
#7
Senior Member
SuperBike
Thread Starter
Join Date: May 2007
Location: Austin, Texas
Posts: 1,283
I'm taking the bike over to a buddy's house this evening (schedule permitting) to see if we can figure it out.
The second set of hands, and eyes, should be useful and we'll try some of the techniques you guys mentioned.
FWIW, the bike is an '03 RC51 and there's no visible fluid leaks
The second set of hands, and eyes, should be useful and we'll try some of the techniques you guys mentioned.
FWIW, the bike is an '03 RC51 and there's no visible fluid leaks
09-01-2011, 09:31 AM
#8
Senior Member
SuperBike
Thread Starter
Join Date: May 2007
Location: Austin, Texas
Posts: 1,283
Loaded up the bike, took it to my buddy's house and started looking over the bike.
We agreed no fluid was leaking and everything appears to be, visually, fine.
Started messing with the lever and.... after a minute or two of just pumping the lever, with everything connected, the pressure had built up enough to lock the front tire while riding.
So, now that it's got pressure, we're letting it sit as is for a couple days to see if it stays. If the pressure stays, then it's all good... if it bleeds off, I'll try the lever zip tie option. If that doesn't work, I'll rebuild the master.
We agreed no fluid was leaking and everything appears to be, visually, fine.
Started messing with the lever and.... after a minute or two of just pumping the lever, with everything connected, the pressure had built up enough to lock the front tire while riding.
So, now that it's got pressure, we're letting it sit as is for a couple days to see if it stays. If the pressure stays, then it's all good... if it bleeds off, I'll try the lever zip tie option. If that doesn't work, I'll rebuild the master.
04-11-2012, 08:47 AM
#9
Senior Member
Superstock
Join Date: Oct 2011
Location: Pompano Beach, Fl.
Posts: 273
Update?
Loaded up the bike, took it to my buddy's house and started looking over the bike.
We agreed no fluid was leaking and everything appears to be, visually, fine.
Started messing with the lever and.... after a minute or two of just pumping the lever, with everything connected, the pressure had built up enough to lock the front tire while riding.
So, now that it's got pressure, we're letting it sit as is for a couple days to see if it stays. If the pressure stays, then it's all good... if it bleeds off, I'll try the lever zip tie option. If that doesn't work, I'll rebuild the master.
We agreed no fluid was leaking and everything appears to be, visually, fine.
Started messing with the lever and.... after a minute or two of just pumping the lever, with everything connected, the pressure had built up enough to lock the front tire while riding.
So, now that it's got pressure, we're letting it sit as is for a couple days to see if it stays. If the pressure stays, then it's all good... if it bleeds off, I'll try the lever zip tie option. If that doesn't work, I'll rebuild the master.
I hate to ask but what was the fix on this brake issue?
02-23-2017, 08:23 AM
#10
Junior Member
Squid
Join Date: Feb 2017
Posts: 1
Front brake bleeding problems
Yeah brakes can be frustrating. Have you tried bleeding at the banjo bolt at the lever? I have found thats the only way to get all the air out on the clutch too even with a mityvac bleeder.
Just wrap a rag around the banjo, pump & hold the lever, crack the banjo bolt loose enuff to expel air and a bit of fluid, and tighten the bolt while you are still holding the lever. Presto, problem gone.
Just wrap a rag around the banjo, pump & hold the lever, crack the banjo bolt loose enuff to expel air and a bit of fluid, and tighten the bolt while you are still holding the lever. Presto, problem gone.
After a few weeks of tinkering with this - I had replaced brake/clutch lines with braided SS - just couldn't get fronts to bleed. The suggestion to bleed at upper banjo fixed it immediately. Thank you!!
Thread
Thread Starter
Forum
Replies
Last Post
pbfiredawg22
Technical Discussion
14
09-08-2010 05:48 PM
