Brakes gone soft after Track Day?
Discussion
Having issues with the brakes on the R1 ... at the weekend I swapped the pads out as they were getting low and chucked some Ferrodo pads I had sitting on the bench... bedded them in on the commute ready for the track day.
On track for the first couple sessions they were fine with a solid lever but gradually I was having to pull the brakes harder with each lap and started to get hand cramp as the lever was softening ... came in and as the bike cooled the lever stiffened slightly but was still softer than usual...
At lunch swapped the pads out for some SBS RS and note the Ferrodo pads were glazed to hell - look like they had overheated / faded? ... now have braking power but the lever was still softer than usual but managed fine on track.
Last night putting the bike back into road trim I gave the brakes a quick bleed... the lever is still a bit soft.
Any ideas?
Fluid a year old now so reckon a full fluid change wouldn't hurt but other than that I'm out of ideas.
On track for the first couple sessions they were fine with a solid lever but gradually I was having to pull the brakes harder with each lap and started to get hand cramp as the lever was softening ... came in and as the bike cooled the lever stiffened slightly but was still softer than usual...
At lunch swapped the pads out for some SBS RS and note the Ferrodo pads were glazed to hell - look like they had overheated / faded? ... now have braking power but the lever was still softer than usual but managed fine on track.
Last night putting the bike back into road trim I gave the brakes a quick bleed... the lever is still a bit soft.
Any ideas?
Fluid a year old now so reckon a full fluid change wouldn't hurt but other than that I'm out of ideas.
Fleegle said:
Glazing can be a bit of an issue from time to time due to the heat, normally sorted by rubbing flat across the garage floor and cleaning with brake cleaner to wash the dust out.
Sounds to me more like your fluid is past its best
Will swap the fluid out tonight then. Cheers.Sounds to me more like your fluid is past its best
cjb1 said:
Definitely fluid, I had the same issue with my 911, changed fluid from 4.1 DOT to 5.0 DOT ( I think those are the right specs????). Never had a problem with brake fade since, good luck fixing the problem.
I use high spec DOT 4 ATE Blue which has in most cases better dry / wet boiling temps than most DOT 5.1sc0tt said:
I'm wondering if your Master Cylinder is possibly leaking?
Mine is a bit squidgy. Haven't had it sorted yet but 3dp gave me the technical reason.
I know JBL has/had the same issue aswell.
Funny you say that as I've been looking at an upgrade MC anyway... Mine is a bit squidgy. Haven't had it sorted yet but 3dp gave me the technical reason.
I know JBL has/had the same issue aswell.
Based on that reply I'm going to bleed the MC again tonight as being a total w
e I've got some nice clear hose for the MC reservoir to show off the ATE blue fluid ... 
Shadow R1 said:
Mine has sbs pads, hel lines with normal dot 4.
No problems with it, lever is fine, not soft or anything.
Do all your pistons move freely ?
When bleeding the system, did you crack the one on the end of the master cylinder to bleed that ?
Make sure you put a rag underneath.
Last night I spent some time getting the pistons as far out as possible (a couple escaped lol)... ensuring they were immaculate and easy to push home and all pumped out at a similar rate. Was surprised to find copper grease under a couple of the pistons so cleaned all that out. A light smear of red grease before pressing home... No problems with it, lever is fine, not soft or anything.
Do all your pistons move freely ?
When bleeding the system, did you crack the one on the end of the master cylinder to bleed that ?
Make sure you put a rag underneath.
Then a full brake fluid change, swapped out MC hose (as I'm a tart) ... bled the MC first, then the furthest caliper and then the nearest... did again for hell of it and then tied the lever back overnight with reservoir cap off and this morning...
I have a rock hard lever
... Sounds like the calipers needed a proper clean up TBH... surprised as they weren't that dirty (this is me we are talking about) but a couple were a tiny bit sticky...
Tempted to pop them off the bike and do the job properly soon.
Edited by Mr OCD on Thursday 24th April 10:10
oOTomOo said:
Please don't ask me to explain why, but as I understand it, air bubbles rise more readily under pressure. By doing the above, you're putting pressure on the brake system and making the master cylinder the highest point of the system. Therefore, tiny bubbles would rise to the master cylinder, then be bled into the reservoir when the pressure is released.
It's also possible that if the seals are a little sticky and pulling the piston too far back into the caliper, the first part of "squish" in the lever is filling the gap to the disk. If you force (and keep) the pistons out, the seals will settle farther down the piston, causing some of this travel to be removed.
That's how I understood it too.... It's also possible that if the seals are a little sticky and pulling the piston too far back into the caliper, the first part of "squish" in the lever is filling the gap to the disk. If you force (and keep) the pistons out, the seals will settle farther down the piston, causing some of this travel to be removed.
No bubbles when I released the lever but so far - so good... back to one finger pressure at the lever.
Cunny DK said:
As for pads damaging discs, this can happen if you fit road pads and do a track day and glaze your pads if they haven't been bed in properly. They then become brittle and begin break up. You then wear partial grooves in your discs and when new pads are fitted you end up braking on the high spots which only give partial brake performance. Look at the picture above.
The grooves were old brake pad material / residue coming off from the old OE pads...They disappeared pretty quickly using the SBS RS pads which is what I've stuck with... If going to change pad type it would be a good idea to remove old pad residue before you fit them... I didn't get time as I was in the middle of a track day.
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