Front Break issue

Italian twin · May 25, 2015

Front Brake issue

Hi guys. I have an issue with my front brakes in that they judder when in use.
No, its not warped disks, i have had them checked and straightened (only slightly out) by a specialist garage. Disks arent too worn.
I have loosened the circlips to turn the disks into full floaters, they rattle nicely.
Seems like my headstock bearings are fine / no movement.
Forks seem to be in order. Calipers + pads cleaned. Front tire is almost new.
I havent lost any fluid and its clean.
Even at slow speed, feathering the leaver its off and on braking.

Any idears? Could it be the slave cylinder?
Any help appreciated.

RSV_Ecosse · May 25, 2015

When you cleaned the calipers did you try removing them and checking the pistons to see if any are sticky? Give 'em a good clean and flush out all the crud which accumulates in there then make sure the pistons move out smoothly. Clean all around the piston bodies and give 'em a wipe with brake fluid then retract them again. Do that a few times to see if it helps. Worth a shot if you haven't done it already. If yer discs are true and the disc carrier bobbins are spinning freely then that's what my next move would be.

Italian twin · May 25, 2015

Thanks for the reply Ecosse.
I took the calipers off and sprayed break cleaner inside then levered the pistons back and forth. They moved freely. One thing I did notice is that one of the pads was allot lower than the rest. I gave this piston more attention incase it hadnt been retracting properly. Still to no avail on the judder?

butchersdog · May 27, 2015

Has the wheel been properly balanced, ie not on a machine?

Rybes · May 27, 2015

my missus vfr suffers from the same, it needs fork bushes doin. when i get round to it lol. it could be those if the brakes are ok

Italian twin · May 27, 2015

Wheel has been balanced but was on a machine. The feeling of on off braking when feathering at low speed makes me think its not a fork issue, the high speed judder i could have put down to it.

Gray · May 28, 2015

Italian twin said:
Hi guys. I have an issue with my front brakes in that they judder when in use.
No, its not warped disks, i have had them checked and straightened (only slightly out) by a specialist garage. Disks arent too worn.
I have loosened the circlips to turn the disks into full floaters, they rattle nicely.

Even at slow speed, feathering the leaver its off and on braking.

Any help appreciated.

I personally would replace suspected "warped" discs. I wouldn't even accept the word of an "expert" garage that the discs were ok - these are your main brakes !!! Why have you altered the discs to be "full floaters" ???I assume that you have changed the pads as you noticed uneven wear when you cleaned the calipers??? Did you finally achieve even extension of all pistons??? Have you bled the system a few times to ensure there is no air anywhere (ie trapped in the calipers or the master cyl or the slave cyl or even in the lines) if you haven't done a rigorous bleed then I would recommend that you spend the time doing this before trying anything else.

Good luck
Gray

Pottsy1 · May 28, 2015

I have the same issue. Front brakes pulsing
Was given as an advisory at my last MOT in April
The tester (extremely competent on bikes) recons the discs need changing.
Winter Project me thinks
Pottsy

butchersdog · May 28, 2015

Well cheapest option to start is get the front balanced by hand prob only a fiver and then you can at least discount this. Friend had the same pulsing on a brand new HP4 and it was balancing, machines are no good for bike wheels, he had his done at the track and problem sorted.

Gray · May 28, 2015

butchersdog said:
Well cheapest option to start is get the front balanced by hand prob only a fiver and then you can at least discount this. Friend had the same pulsing on a brand new HP4 and it was balancing, machines are no good for bike wheels, he had his done at the track and problem sorted.

I've always had my wheels balanced by machine when new tyres fitted and I can't recall ever having an issue, and I've had 10 different bikes, so that amounts to a load of times. Maybe I've always been lucky :dunno

There is one other thing you could consider trying - if the bike has been wheelied a lot or bumped hard up the kerb - there is the possibility that the forks are misaligned. This is easy to correct and there are videos on YouTube (check out Del boy's garage )

Gray

butchersdog · May 29, 2015

Gray said:
I've always had my wheels balanced by machine when new tyres fitted and I can't recall ever having an issue, and I've had 10 different bikes, so that amounts to a load of times. Maybe I've always been lucky :dunno

There is one other thing you could consider trying - if the bike has been wheelied a lot or bumped hard up the kerb - there is the possibility that the forks are misaligned. This is easy to correct and there are videos on YouTube (check out Del boy's garage )

Gray

Gray you maybe right, just that the Guy at Parkitt Racing knew his stuff and found that even my mates "machine balanced wheel" was well out at Aragon this year and he was worried it was warped discs too.

echelon · Jun 16, 2015

Hi There

Check the steering head bearings and make sure it's not a little bit loose then try it again once it has been tightened up. I had the same problem and it seemed to sort that problem out.

Front Break issue

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Italian twin

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Italian twin

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butchersdog

Gray

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