Front brake spongy
Discussion
Had my bike checked over by mechanic after dropping it. They noticed that both brake reservoirs were full and over the max line. They syringed out the excess fluid, but I now find the front brake very spongy. I use the bike to pick up prescriptions. What can I do as no bike shops open.
mjw7 said:
Had my bike checked over by mechanic after dropping it. They noticed that both brake reservoirs were full and over the max line. They syringed out the excess fluid, but I now find the front brake very spongy. I use the bike to pick up prescriptions. What can I do as no bike shops open.
Syringing fluid out of the reservoir shouldn't have introduced any air in to the system and I am surprised that they would choose to do this rather than just crack a bleed nipple open and run some out of the caliper instead (much less hassle).Either way, it's not exactly difficult to bleed your brakes yourself; check it out online and spend 20 minutes getting to know your bike.
In t'old days when I bled brakes as soon as you finished and tightened the nipples the levers would be rock solid. But now with ABS (OK, first bike with ABS) I tried for bloody ages to get a solid lever, but once I gave up and just 'tickled' the lever lightly for a while they got hard (ooh er missus). And after some experimentation it seemed every time I ran fluid through the system the brakes got/stayed spongy until I closed the nipples off and 'tickled' the lever to firm things up. I know I wasn't introducing air into the system, and by 'tickling' I mean pulling the lever really lightly until you just start to feel resistance then ease off, and repeat multiple times a second. I'm wondering is there some trickery in ABS systems that needs to get pumped up or pressurised after the fluid moves in the system?
tvrolet said:
In t'old days when I bled brakes as soon as you finished and tightened the nipples the levers would be rock solid. But now with ABS (OK, first bike with ABS) I tried for bloody ages to get a solid lever, but once I gave up and just 'tickled' the lever lightly for a while they got hard (ooh er missus). And after some experimentation it seemed every time I ran fluid through the system the brakes got/stayed spongy until I closed the nipples off and 'tickled' the lever to firm things up. I know I wasn't introducing air into the system, and by 'tickling' I mean pulling the lever really lightly until you just start to feel resistance then ease off, and repeat multiple times a second. I'm wondering is there some trickery in ABS systems that needs to get pumped up or pressurised after the fluid moves in the system?
What you are doing here encourages lots of little bubbles to become one big bubble; it's a great way of getting air to work its way up the lines from the calipers to the master cylinder.There is no trickery in ABS (except the magic that makes it work in the first place) so it doesn't need bled in any particular way (although check the abs unit itself to see if it has a bleed nipple as this helps to change the fluid inside the unit that doesn't move unless it has kicked in).
Had similar with my '04 ZX10R
Never a heavy braker but lever finally worked its way back too close to the bar
Tried bleeding loads but no better
No fluid being lost, braded lines, discs straight and free, all looked in good condition, not a complicated system so got to be something simple...
Turned out to be the seals in the callipers pulling the pistons back slightly from the discs
Rebuilt with all new seals and, what seems to be the important bit, red rubber grease rather than just brake fluid on them and were absolutely solid from then on
SBS street pads just gone in to replace the crappy EBCs, big difference there too
Never a heavy braker but lever finally worked its way back too close to the bar
Tried bleeding loads but no better
No fluid being lost, braded lines, discs straight and free, all looked in good condition, not a complicated system so got to be something simple...
Turned out to be the seals in the callipers pulling the pistons back slightly from the discs
Rebuilt with all new seals and, what seems to be the important bit, red rubber grease rather than just brake fluid on them and were absolutely solid from then on
SBS street pads just gone in to replace the crappy EBCs, big difference there too
mjw7 said:
Had my bike checked over by mechanic after dropping it. They noticed that both brake reservoirs were full and over the max line. They syringed out the excess fluid, but I now find the front brake very spongy. I use the bike to pick up prescriptions. What can I do as no bike shops open.
The reservoirs won't fill up with fluid unless it's being pushed back up from the caliper. Assuming it wasn't full already ? I wonder if there's been any damage to the pipes or caliper on the dropped side ? Need to have it checked.Didn’t know it was such a modern bike with latest ABS when offering my cable tie advice.
Rubin215 said:
There is no trickery in ABS (except the magic that makes it work in the first place) so it doesn't need bled in any particular way (although check the abs unit itself to see if it has a bleed nipple as this helps to change the fluid inside the unit that doesn't move unless it has kicked in).
You sure it doesn’t have a weird bleeding sequence? I watched a mechanic mate doing a late model FireBlade with ABS and he said “what do you think of that?” pumping the front brake, it felt great so I said so and he said that it was good enough to stop the bike in the workshop but almost zero brakes out on the road. The sequence was described over a few sheets of A4 with various black boxes & things needed to beep to inform you they had done their thing.Gassing Station | Biker Banter | Top of Page | What's New | My Stuff