Calling superhawk22 or jschmidt
06-07-2006, 02:48 PM
#1
Senior Member
SuperSport
Thread Starter
Join Date: Dec 2005
Location: Sunshine Coast, Australia
Posts: 963
Calling superhawk22 or jschmidt
G'day guys.
From memory you two guys have changed calipers on your bikes. I am having some brake issues and would appreciate your help.
I have the standard calipers however have done a full rebuild on them and changed to braided lines, so the system is empty of fluid. I have bled the master cylinder and the lines no problem, and the bleed hose will show clear fluid no matter how much you pump through. You can put fluid through until the cows come home (Aussie expression meaning a long time!) and no bubbles will show. However the lever is spongy and will compress back to the bar.
I tied the lever back overnight and then cracked the bleed nipples again and got a couple of air bubbles out after one pump of the lever, however after that it is clear fluid again. Tie the lever back overnight though and the next day you can get another couple of air bubbles out of each caliper again. This is very slowly improving the lever feel, but I am gunna be too old to ride any more before it is any good!
My guess is that air is caught in the caliper, and that compressing the system overnight is forcing a bit of it out each time I do it. I have never heard of this problem before, I have never come across it. I have a brake bleeding tool with a one way type valve on it, but it is not a vacuum type uint.
Do you think air may be caught in the caliper?
Is getting a vacuum tool possibly the way to fix it?
Any help would be appreciated.
Cheers,
Shayne
From memory you two guys have changed calipers on your bikes. I am having some brake issues and would appreciate your help.
I have the standard calipers however have done a full rebuild on them and changed to braided lines, so the system is empty of fluid. I have bled the master cylinder and the lines no problem, and the bleed hose will show clear fluid no matter how much you pump through. You can put fluid through until the cows come home (Aussie expression meaning a long time!) and no bubbles will show. However the lever is spongy and will compress back to the bar.
I tied the lever back overnight and then cracked the bleed nipples again and got a couple of air bubbles out after one pump of the lever, however after that it is clear fluid again. Tie the lever back overnight though and the next day you can get another couple of air bubbles out of each caliper again. This is very slowly improving the lever feel, but I am gunna be too old to ride any more before it is any good!
My guess is that air is caught in the caliper, and that compressing the system overnight is forcing a bit of it out each time I do it. I have never heard of this problem before, I have never come across it. I have a brake bleeding tool with a one way type valve on it, but it is not a vacuum type uint.
Do you think air may be caught in the caliper?
Is getting a vacuum tool possibly the way to fix it?
Any help would be appreciated.
Cheers,
Shayne
06-07-2006, 03:45 PM
#2
Senior Member
MotoGP
Join Date: Jan 2005
Location: Gainesville FLA.
Posts: 3,844
Call me old school but I like to bleed my brakes by hand, I always start at the master. Crack the bolt open just enough to get fluid out, depress all the way and hold it, tighten the bolt while holding and repeat until no air. Then move to the caliper furthest from the master, give it 3 slow pumps, hold the last and then open, close and repeat. Keep a close eye on the fluid so you don't pump air back into the system, you don't want to save the fluid anyway so use a lot. Move to the other side and do the same, if you're still having issues after that then you have a leak somewhere. Sometimes if the washers are old and have been compressed many times they can leak just enough to suck air in. Good luck oh and the cows come home here too.
06-07-2006, 06:58 PM
#3
Senior Member
SuperSport
Join Date: Mar 2005
Location: Laurel, MD
Posts: 758
I've never been a fan of the vacuum bleeder either, even though I have one. Brake bleeding requires patience, though. I don't see any way that air could become trapped in the caliper. The bleed screw is at the top.
Anyway, tell us exactly the steps you're using. Was it a used master cylinder? Pull the boot back and see if you see any fluid there. It's also possible that it doesn't push fluid properly even if it doesn't leak. Another possibility is that the bleed hole is clogged.
Have you adjusted the lever? If it is set full in it can feel like the brakes are spongy.
Anyway, tell us exactly the steps you're using. Is there any possibility you may be having a technique problem?
Anyway, tell us exactly the steps you're using. Was it a used master cylinder? Pull the boot back and see if you see any fluid there. It's also possible that it doesn't push fluid properly even if it doesn't leak. Another possibility is that the bleed hole is clogged.
Have you adjusted the lever? If it is set full in it can feel like the brakes are spongy.
Anyway, tell us exactly the steps you're using. Is there any possibility you may be having a technique problem?
06-07-2006, 07:28 PM
#4
Member
Squid
Join Date: Jul 2005
Posts: 90
Shayne, can't help you with any info myself and not to hijack your thread but I got a brake question here that might help you too. I ordered speed bleeders with my new Spiegler lines and bar risers. Have not used speed bleeders before and was wondering if anybody out there had ? They sound pretty handy by most accounts.
06-07-2006, 07:32 PM
#5
Senior Member
SuperBike
Join Date: Nov 2005
Posts: 1,011
i like my vacuum bleeder but probably will have to replace it soon because I've dropped it too many times... I tend to use a combination of each. starting out with the vacuum bleeder works wonders for moving lots of fluid to get pressure in the lines
06-07-2006, 08:56 PM
#6
Moderator
MotoGP
Join Date: Dec 2004
Location: South Texas
Posts: 2,553
I use a mityvac to get a "new" system filled. After that, I use the manual hand pump method (no jokes puh-leeeze). Slow pumps, hold, and a slight release on the bleed screw as you pull the lever the rest of the way.
You could have air leaks on the screws themselves too. Teflon tape. I also second the thought about checking your lever travel adjuster. Move it all the way out and see if it feels different.
You could have air leaks on the screws themselves too. Teflon tape. I also second the thought about checking your lever travel adjuster. Move it all the way out and see if it feels different.
06-08-2006, 03:47 AM
#7
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SuperSport
Thread Starter
Join Date: Dec 2005
Location: Sunshine Coast, Australia
Posts: 963
Thanks guys.
As I have not ridden the bike yet, I had no idea where the lever was. As it turns out it was fully in, so adjusting it back out a bit has made a bit of difference. But compared to my Suzuki DL 650 and KTM it is still spongy.
I have bled the master cylinder, and no bubbles are coming out of the bleeder hole now.
Calipers fully rebuilt.
Master cylinder was stripped and cleaned and re-assemled. Only 10000 miles on it.
All lines are new stainless with new washers etc. I cannot see any leaks, even when the system is left compressed.
Left compressed overnight you can get a coulple of air bubbles out of each caliper, and then no more, until leaving it another day.
If I am doing something wrong Jim, I am not sure what it is. However this is the reson for asking you guys, before I assume something is wrong with the system and start pulling things apart. What makes me think there is air caught in the caliper is those air bubbles I am getting, and the fact that it is very slowly getting better.
Using the brake tool you can crack the bleeder and let it gravity flow a bit without gatting air in. When you do this clean fliud with no air comes out slowly. If you pump the lever then you get the air bubbles. One theory I have is that he fluid is taking a short cut from the line to the bleeder, and not running through the whole caliper, thus not getting all the air out. But if you guys have not heard of this problem I will rule it out.
Got me puzzled!
As I have not ridden the bike yet, I had no idea where the lever was. As it turns out it was fully in, so adjusting it back out a bit has made a bit of difference. But compared to my Suzuki DL 650 and KTM it is still spongy.
I have bled the master cylinder, and no bubbles are coming out of the bleeder hole now.
Calipers fully rebuilt.
Master cylinder was stripped and cleaned and re-assemled. Only 10000 miles on it.
All lines are new stainless with new washers etc. I cannot see any leaks, even when the system is left compressed.
Left compressed overnight you can get a coulple of air bubbles out of each caliper, and then no more, until leaving it another day.
If I am doing something wrong Jim, I am not sure what it is. However this is the reson for asking you guys, before I assume something is wrong with the system and start pulling things apart. What makes me think there is air caught in the caliper is those air bubbles I am getting, and the fact that it is very slowly getting better.
Using the brake tool you can crack the bleeder and let it gravity flow a bit without gatting air in. When you do this clean fliud with no air comes out slowly. If you pump the lever then you get the air bubbles. One theory I have is that he fluid is taking a short cut from the line to the bleeder, and not running through the whole caliper, thus not getting all the air out. But if you guys have not heard of this problem I will rule it out.
Got me puzzled!
06-08-2006, 06:04 AM
#8
Senior Member
Superstock
Join Date: May 2006
Location: New Jersey USA
Posts: 284
It is posible to get air traped in the caliper!! When you bleed the system tap on the calipers with a plastic hammer or one that wouldn't damage it. This will help to disloge air klinging to the inside or being traped.
I have seen bleed screws that were overthightened and distorted the tapered end that seals in the caliper oblonging the bleed hole of the screw. Remove and check reinstall with teflon tape on the threads.
If bleeding by hand use severial rubber bands on the lever to grip this will help hold the lever from releasing from the grip. Especialiy usefull for maintaining pressure on the system overnight.
I have seen bleed screws that were overthightened and distorted the tapered end that seals in the caliper oblonging the bleed hole of the screw. Remove and check reinstall with teflon tape on the threads.
If bleeding by hand use severial rubber bands on the lever to grip this will help hold the lever from releasing from the grip. Especialiy usefull for maintaining pressure on the system overnight.
06-08-2006, 09:29 AM
#11
Junior Member
Squid
Join Date: Jun 2006
Location: Mankato, Mn
Posts: 28
here's my tips for final bleeding
PATIENCE IS KEY!!!! tiny bubbles need time to float up to the highest point of the brake system...
if you have brake pressure, place the bike on the sidestand and turn the handle bars all the way to the left to assure the master cylinder is at it's highest point... stand next to the bike and just flick the tip of the lever so that your jarring the fluid in the entire system... each of the banjo bolts, any joints, the calipers have tons of area for the bubbles to hide while your doing this, have the master cylinder resoivor (sp?) cap off so you can see the little bubbles flowing up. this jarring of the suspension fluid will knock trapped bubbles free and help them rise to the master cylinder, i can spend 10 minutes or more doing this and seeing bubbles still rise up to the resivoir.. i also do a squeeze and release, like releasing an arrow from a bow, squeeze the lever and let your fingers slide off it so it flicks itself out... the fluid will compress, then any trapped air will force itself and fluid back into the master cylinder... this also takes time, do it ALOT and be patient...
another thing i do is using a thin pry bar or tire iron, VERY GENTLY TO NOT BEND THE ROTOR pry the pads back into the caliper (this can be done with the calipers removed... keep the banjo bolt inlet to the hose at the highest point so any trapped bubbles will be forced up) keep an eye on your fluid level so you don't get any on the painted parts.. this forces fluid back UP the system to the highest point, taking any trapped air with it.. walk away from the bike, grab a beer, smoke, poweraide, whatever, and let the air have some time to float to the uppermost point... if you immediately pump the system back up your just pumping the bubbles back down...
mitivacs work well for initial priming of the brakes, but patience and these tricks should improve your stopping performance...
any other ???'s let me know... (i'm a MMI grad with HONTECH and own my own shop)
PATIENCE IS KEY!!!! tiny bubbles need time to float up to the highest point of the brake system...
if you have brake pressure, place the bike on the sidestand and turn the handle bars all the way to the left to assure the master cylinder is at it's highest point... stand next to the bike and just flick the tip of the lever so that your jarring the fluid in the entire system... each of the banjo bolts, any joints, the calipers have tons of area for the bubbles to hide while your doing this, have the master cylinder resoivor (sp?) cap off so you can see the little bubbles flowing up. this jarring of the suspension fluid will knock trapped bubbles free and help them rise to the master cylinder, i can spend 10 minutes or more doing this and seeing bubbles still rise up to the resivoir.. i also do a squeeze and release, like releasing an arrow from a bow, squeeze the lever and let your fingers slide off it so it flicks itself out... the fluid will compress, then any trapped air will force itself and fluid back into the master cylinder... this also takes time, do it ALOT and be patient...
another thing i do is using a thin pry bar or tire iron, VERY GENTLY TO NOT BEND THE ROTOR pry the pads back into the caliper (this can be done with the calipers removed... keep the banjo bolt inlet to the hose at the highest point so any trapped bubbles will be forced up) keep an eye on your fluid level so you don't get any on the painted parts.. this forces fluid back UP the system to the highest point, taking any trapped air with it.. walk away from the bike, grab a beer, smoke, poweraide, whatever, and let the air have some time to float to the uppermost point... if you immediately pump the system back up your just pumping the bubbles back down...
mitivacs work well for initial priming of the brakes, but patience and these tricks should improve your stopping performance...
any other ???'s let me know... (i'm a MMI grad with HONTECH and own my own shop)
06-08-2006, 02:49 PM
#12
Senior Member
SuperSport
Thread Starter
Join Date: Dec 2005
Location: Sunshine Coast, Australia
Posts: 963
Some good tips here guys, thank you.
No air bubbles in the reservoir for a while now. But crack that bleeder and they appear with one lever pump, so the air is coming from low in the system it seems. I will try these tricks you mention with the calipers and see how I go. I am off fishing for 4 days now, so will have a crack at it when i get home and let you know how it all went.
Cheers,
Shayne
No air bubbles in the reservoir for a while now. But crack that bleeder and they appear with one lever pump, so the air is coming from low in the system it seems. I will try these tricks you mention with the calipers and see how I go. I am off fishing for 4 days now, so will have a crack at it when i get home and let you know how it all went.
Cheers,
Shayne
06-08-2006, 02:58 PM
#14
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SuperSport
Thread Starter
Join Date: Dec 2005
Location: Sunshine Coast, Australia
Posts: 963
Thanks. I have done a lot of brakes over the years, but this is the first time I have done a caliper rebuild, and then started with a dry system. Just need to learn a few more tricks it seems!
06-08-2006, 09:45 PM
#15
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SuperSport
Join Date: Mar 2005
Location: Laurel, MD
Posts: 758
Originally Posted by shayne
Using the brake tool you can crack the bleeder and let it gravity flow a bit without gatting air in. When you do this clean fliud with no air comes out slowly. If you pump the lever then you get the air bubbles. One theory I have is that he fluid is taking a short cut from the line to the bleeder, and not running through the whole caliper, thus not getting all the air out. But if you guys have not heard of this problem I will rule it out.
Got me puzzled!
OK, here's an important tip. You can't let the brake lever bottom out when you are bleeding and you must release it gradually. If you let the lever bottom, you can get some reversion back into the caliper which can sometimes lead to air. If you release the lever quickly it is (infrequently) possible to suck some air through the fluid into the master even though there is some fluid in the resorvoir.
You also cannot release the brake lever until you have closed the bleed valve. If you release it before, you'll get air.
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