Looks a little soft, what type of Master Cylinder is it?
Helps if you list what bike it's on.
Helps if you list what bike it's on.
brake firmness
Hi,
Can anyone tell me if this looks like 'normal' brake firmness:
After the dealership replaced the fluid I had brake fade after 20 minutes on track. So I bled them with Castrol Race fluid.
At one point I did get air into the lines however.
I just cannot remember how they felt before all this and although they brake fine on the street I cannot shed the feeling they where more firm before all this. Espescially after I tried an R6 of a friend. The R6 had smaller levers, so that might make the difference in feel.
I've tried everything; bleed the brakes , ziptie overnight, bleed again, lift the left caliper over the brake line loop to get any potential bubbles out of the loop over the wheel. bleed again. Granted I didn't do a full blead each time just a bit and each time I didn't see any bubbles come out.
Can anyone tell me if this looks like 'normal' brake firmness:
After the dealership replaced the fluid I had brake fade after 20 minutes on track. So I bled them with Castrol Race fluid.
At one point I did get air into the lines however.
I just cannot remember how they felt before all this and although they brake fine on the street I cannot shed the feeling they where more firm before all this. Espescially after I tried an R6 of a friend. The R6 had smaller levers, so that might make the difference in feel.
I've tried everything; bleed the brakes , ziptie overnight, bleed again, lift the left caliper over the brake line loop to get any potential bubbles out of the loop over the wheel. bleed again. Granted I didn't do a full blead each time just a bit and each time I didn't see any bubbles come out.
1 - 16 of 16 Posts
Just guessing from his profile that its a 2011 848...
That looks normalish to me. But if I were you, I'd take my time and do a thorough bleed. Start at the far side caliper, go to the right side and then bleed the master. Go slow and don't let the reservoir run dry. Do three or four good bleeds per screw and do the circuit two or three times. If your really patient, try a gravity bleed. Put a hose on the bleed screw, open the reservoir and then crack the bleed screw ( don't touch the lever!). This can take awhile but I just went through popping a piston out of a caliper and the gravity bleed was the most effective getting fluid fully back in the system. Do them one at a time in the same order, furthest to closest.
OK thx, I'll try a full bleed again.
How long would it roughly take doing it this way?
So if you open up the bleed valve and you don't touch the lever no air will get into the bleed valve?That looks normalish to me. But if I were you, I'd take my time and do a thorough bleed. Start at the far side caliper, go to the right side and then bleed the master. Go slow and don't let the reservoir run dry. Do three or four good bleeds per screw and do the circuit two or three times. If your really patient, try a gravity bleed. Put a hose on the bleed screw, open the reservoir and then crack the bleed screw ( don't touch the lever!). This can take awhile but I just went through popping a piston out of a caliper and the gravity bleed was the most effective getting fluid fully back in the system. Do them one at a time in the same order, furthest to closest.
How long would it roughly take doing it this way?
You only want to open the bleed valve while pressure is being put on the brake lever.
Without a second person helping, you can get a bleed tube from MotionPro that has a one way valve or a SpeedBleeder valve, which again is one way.
Without a second person helping, you can get a bleed tube from MotionPro that has a one way valve or a SpeedBleeder valve, which again is one way.
Having an extra set of hands helps..
Are you still using that Castrol Race Fluid?
Are you still using that Castrol Race Fluid?
Yes still using Castrol.
Yesterday I redid the whole thing but still the same result. I tied the left caliper up high overnight to allow any bubbles to travel up to the caliper and rebleed that caliper later today.
One question, do you guys close the nipple before you get to the handlbar with the lever?
Yesterday I redid the whole thing but still the same result. I tied the left caliper up high overnight to allow any bubbles to travel up to the caliper and rebleed that caliper later today.
One question, do you guys close the nipple before you get to the handlbar with the lever?
Yes left caliper, then right, then master.
Did a bleef again after having good tied the left caliper up high. No difference, zip tied the lever, and will check tomorrow.
After this I m giving up. Don't know ow what to do anymore.
Did a bleef again after having good tied the left caliper up high. No difference, zip tied the lever, and will check tomorrow.
After this I m giving up. Don't know ow what to do anymore.
Was the lever throw adjusted by the dealership, by chance? Might have too much free travel.
Don't think so. Free play seems fine ,then when I hit resistance, there still is some mushyness. im wondereing if there's something with the seals.
Here are a couple of ideas.
1. Sometimes air gets trapped in small pockets, and this has happened to me a few times before. You can try tapping on the fittings and on the caliper as you bleed to try to get it resolved. Another tactic is to squeeze really hard with the bleed nipple closed, and loosen it so that there's a strong rush of fluid.
2. The bleed nipples let air in the sides when you let up in the brakes while bleeding, so During the last part of the brake bleeding, close the nipple while still squeezing. Also, using a mighty-vac helps with this.
3. When installing the calipers and squeezing the brake lever so that the pads contact the rotors, go in very small squeezes, so that it takes the caliper a little while to get there, instead of one or two big squeezes. The one big squeeze will distort the caliper seals which have a square cross section, and this can cause a spongy feeling and caliper drag with the calipers not retracting properly.
4. Last resort, rebuild the master and calipers with new seals, and clean everything well, and start over.
1. Sometimes air gets trapped in small pockets, and this has happened to me a few times before. You can try tapping on the fittings and on the caliper as you bleed to try to get it resolved. Another tactic is to squeeze really hard with the bleed nipple closed, and loosen it so that there's a strong rush of fluid.
2. The bleed nipples let air in the sides when you let up in the brakes while bleeding, so During the last part of the brake bleeding, close the nipple while still squeezing. Also, using a mighty-vac helps with this.
3. When installing the calipers and squeezing the brake lever so that the pads contact the rotors, go in very small squeezes, so that it takes the caliper a little while to get there, instead of one or two big squeezes. The one big squeeze will distort the caliper seals which have a square cross section, and this can cause a spongy feeling and caliper drag with the calipers not retracting properly.
4. Last resort, rebuild the master and calipers with new seals, and clean everything well, and start over.
A small bubble of air will get trapped in the banjo fittings.
With an assistant have said monkey apply mediocre pressure to the lever. While pressurized crack the banjo at the master and tighten it before the lever reaches max travel.
And so on down hill to the calipers. Your problem should be solved.
With an assistant have said monkey apply mediocre pressure to the lever. While pressurized crack the banjo at the master and tighten it before the lever reaches max travel.
And so on down hill to the calipers. Your problem should be solved.
Little trick that i learned was to pump the brake lever until you get a nice firm lever, then crack the bleeder. And yes. Shut the bleeder before the lever gets all the way to the handle. Do you have to? No, but its just to make sure that NO air gets sucked back into the bleeder.
1 - 16 of 16 Posts
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