Possible air in front brakes?

[crazbiker4]

Just installed some new lines (Fren Tubo) and pads (EBC HH) on my 09 CBR600rr about 1 month ago but I still think I have air in the front lines? The brakes seem to work pretty good but the lever does not seem solid… it feels somewhat spongy and not as firm as it was before (or I’m just nuts). However when I felt some of the new CBR levers they feel almost the same? I thought by putting steel braded lines on it would stiffen it up a little? A friend of mine put lines on his R6 recently and his lever feels solid, but I was wondering if this had to do with the design of the master between the MFGs?

Has anyone had air issues like this after doing lines? Or do I need to bleed the crap out of them? I have heard of people getting air bubbles stuck in the line and they are hard to get out.

I thought I bled them pretty good because I used the bleeder bags but felt it was not good enough so I got a hand vac.. did not really do much…. Then I tried the Zip tie over night methed, which seemed to help a little. I would like to try to bleed them some more but with some cheaper fluid until I get the feel I want/need then put some new RBF600 in it.

Here is everything I changed:

- Lines (Fren Tubo)

- Pads (EBC HH)

- Speed bleeders all the way around

- Fluid (Motul RBF 600)

- Cleaned calipers very good!

[John]

does your master cylinder have a bleed valve too? you may need to bleed that as well.

sometimes you can get an air bubble in your master cylinder that's kind of tough to get out.

[mojocho]

Well, i was going to suggest the overnight zip tie method, but you tried that. The critical part is ensure all the lines are clear of bubbles. I assume you were watching the lines as you were bleeding the lines? And I further assume kept flushing until all the bubbles were gone? And finally assume as you filled the brake reservoir, you made sure it never went empty while you bled the brakes (i.e. kept it topped off as the reservoir was getting drained?

If so, you should be fine. I don't think the steel lines give you better feel right off the bat. They are to prevent expansion unlike the OEM rubber hose lines. Even then So you'd notice it more under constant hard braking (i.e. at the track or very spirited rides). With OEM lines, there could be a tendency that the lines would expand and you'd feel more "sponginess". Steel lines would prevent that expansion, therefore the sponginess.

When in doubt, bleed the brakes again. It's better to wast a $5 bottle of fluid than lose your brakes. I'm sure more tech literate people will correct me on anything I've posted.

[mello dude]

I had simular issues when I added new lines on my brake redo with RC51 M/C and calipers. I did a couple sessons of bleed it, let it set a day and a few days later dit it again. It wouldnt hurt to bleed yours again. Since you have speed bleeders, try pumping the levers to push fluid thru the system. (- Dont pull the levers all the way back! Leave about an inch between the grip and the lever, and then let the lever back out) - A good brake fluid to use is Valvoline synthetic. I have used in a lot of bikes with no problems.

[crazbiker4]

does your master cylinder have a bleed valve too? you may need to bleed that as well.

sometimes you can get an air bubble in your master cylinder that's kind of tough to get out.

It does, I bled it as well... I will do it again.

Well, i was going to suggest the overnight zip tie method, but you tried that. The critical part is ensure all the lines are clear of bubbles. I assume you were watching the lines as you were bleeding the lines? And I further assume kept flushing until all the bubbles were gone? And finally assume as you filled the brake reservoir, you made sure it never went empty while you bled the brakes (i.e. kept it topped off as the reservoir was getting drained?

If so, you should be fine. I don't think the steel lines give you better feel right off the bat. They are to prevent expansion unlike the OEM rubber hose lines. Even then So you'd notice it more under constant hard braking (i.e. at the track or very spirited rides). With OEM lines, there could be a tendency that the lines would expand and you'd feel more "sponginess". Steel lines would prevent that expansion, therefore the sponginess.

When in doubt, bleed the brakes again. It's better to wast a $5 bottle of fluid than lose your brakes. I'm sure more tech literate people will correct me on anything I've posted.

Yes to all your questions and I was very careful to not dry the MC out. Yea, I was thinking about running some cheap Dot 4 through the system to make sure all the air is out then replace with RBF600.

I had simular issues when I added new lines on my brake redo with RC51 M/C and calipers. I did a couple sessons of bleed it, let it set a day and a few days later dit it again. It wouldnt hurt to bleed yours again. Since you have speed bleeders, try pumping the levers to push fluid thru the system. (- Dont pull the levers all the way back! Leave about an inch between the grip and the lever, and then let the lever back out) - A good brake fluid to use is Valvoline synthetic. I have used in a lot of bikes with no problems.

Dont pull the levers all the way back? is this only on the last pump or each pump?

Thanks for all the help! Like I said, my brakes do work and stop me pretty quick, but I feel that if i was to pull the lever back hard enough then i may be able to hit the bar, most hydro systems i have felt will pull back then stop and will not allow you to go back anymore. On think I want to add is that when I was cleaning the calipers I dumped all the old fluid out... maybe this was a bad idea? I was just wondering if its something honda does with their MC over other MFG. On the good side of things by rear feels solid.

[mello dude]

It does, I bled it as well... I will do it again.

Dont pull the levers all the way back? is this only on the last pump or each pump?

-Each pump untill you are done.

Every master cylinder design can be a little different but the idea is that if the piston is over stroked, some brake fluid can get behind the piston and you are semi-hosed. Then the only way to fix if you did that is disassembly. - To remind myself to not screw up, I like to tape a small piece of wood on the end of the bar, usually like 3/4 inch thick so there's no way in BFE I can overstroke the thing. -- The same thing can happen on the rear. I've seen umpteen threads where guys have effed up this....

See the idea?

Edited April 9, 2012 by mello dude

[crazbiker4]

-Each pump untill you are done.

Every master cylinder design can be a little different but the idea is that if the piston is over stroked, some brake fluid can get behind the piston and you are semi-hosed. Then the only way to fix if you did that is disassembly. - To remind myself to not screw up, I like to tape a small piece of wood on the end of the bar, usually like 3/4 inch thick so there's no way in BFE I can overstroke the thing. -- The same thing can happen on the rear. I've seen umpteen threads where guys have effed up this....

See the idea?

Ok, Ill give it a try and see what happens! Most of the DIY information say to pull the lever back to the bar until your last pump if using speed bleeders you only pull half way to keep pressure in the line.

I see what you are saying, if this would happen would the fluid leak out near the plunger? See link below... bottom photo, opposite side of the banjo bolt.

http://www.howmotorcycleswork.com/images/scans_resized/img016.jpg

[mello dude]

Thats some pretty good pics - hadnt thought about a leak, but you can see if you get fluid behind the plunger(piston) its not gonna be good.

[crazbiker4]

Thats some pretty good pics - hadnt thought about a leak, but you can see if you get fluid behind the plunger(piston) its not gonna be good.

So did a re-bleed last night and ran about 32oz of brake fluid through the system... I think it came out out to about 4 full reservoirs per caliper/master. However I did not see any air come out and my lever still feels about the same, I will check it tonight again since I left a zip tie on the lever.

Another possible issue I ran accross is that the master may need to be rebuilt... kinda sucky if it does since the bike is an 09 with about 10K on it. But it could be possible that one of the seals was bad from the start. I did on the other hand leave the system closed with no fluid in it for about a week when working on it, I wonder if this cause the seal to fail?

[SJC1000rr]

Its a known issue with the 600rr line that the OEM Master Cylinder is kinda crappy. I've had the same problems with my 07. Lemee guess, you have about 1/2-1 inch of play till you get stiffness in the lever? Normal unfortunately. I got the MC seal/rebuild kit last year and did it...and had Reuben rebuild the calipers this year.

Went to Jennings last month and even with new pads the lever was back at my fingers by the end of the day. I finally gave up and got a Brembo 19x18 to replace it with. Just waiting on the reseviour kit to bleed it all out again.

[crazbiker4]

Its a known issue with the 600rr line that the OEM Master Cylinder is kinda crappy. I've had the same problems with my 07. Lemee guess, you have about 1/2-1 inch of play till you get stiffness in the lever? Normal unfortunately. I got the MC seal/rebuild kit last year and did it...and had Reuben rebuild the calipers this year.

Went to Jennings last month and even with new pads the lever was back at my fingers by the end of the day. I finally gave up and got a Brembo 19x18 to replace it with. Just waiting on the reseviour kit to bleed it all out again.

Thanks for the input! It seemed most people with this issue had 07s but Its proabably about the same design for 09. I think you had the same issues as I am having. The pads do compress at the slightest lever pulled, but if I were to hammer it then the lever feels it has to go further then it should and even then it does not feel 100% solid.

Before I go the route of buying a nice Brembo MC I am going to rebuild the master first. Let me know how the Brembo works!

[redkow97]

A friend of mine has his '07 MC on the shelf, and has an aftermarket MC that he likes a lot better.

for my part, the stock '03 has been "acceptable" given its age. I also experience the 1/2-1" of play before anything actually happens, but it improved after bleeding my lines. I think fresh fluid also helped.

But it sounds like you've tried all that and not gotten much help. The aftermarket MC's are definitely better, but I was really trying to keep my bike SuperStock legal

Hopefully i only have this bike a couple more years anyway. We'll see. With a 2009 model, upgrading the MC will be a much more long-term upgrade.

[crazbiker4]

So went to the Honda dealership yesterday to feel how the 2012 CBR brakes feel (1000 and 600) and mine are better feeling then them. It must just be the way Honda brakes feel, ill just need to figure out if I need something more firm feeling or if the way it is will work.