Brake problems

Lately been having some weird brake issues. Usually only occurs on cold
mornings and only for the first km or so of riding.

The brake lever feels very tight ie. I only have to touch it to apply the
brakes hard and can not pull the lever all the way in. Sometimes when this
happens, it feels like the brakes are permanently on as if I put it into
neutral, and try and roll the bike forward or backwards, it wont roll (but
this is not always the case). After a couple of mins riding, this usually
goes away and I brake by pulling the lever all the way in.

Just for reference sake, I did change the front brake pads about 3 months
ago - EBC (I'm not sure if the current problems are related but this problem
did start around this period - prob about a month after changing the pads).

Any ideas?

 

umm no idea...how bout if the low temperature caused the aluminium caliper
to contract and grab the steel piston (are pistons still steel?) , until the
brake warmed up ?
or the piston might be jamming due to uneven pad wear or some such
are the circuits that release pressure when you let go the brake lever
working? (or is yer master cylinder full of crap)<< this may or not be
temperature dependant i spose
how far do you pull the lever in 'normally' when you are braking?
AAH!! if its an old bike and you changed pads recently without cleaning the
pistons properly maybe the crap on the pistons is now jamming in the caliper
bore<< maybe but the problem should get better as the pads wear




Someone let Damien at loose on an internet
connection and the result was:

 

Ahh, don't tell me you changed the pads without the obligatory caliper
clean out? Sheesh ...wake up ol boy! Set yourself about half a day aside
and strip down the front calipers. Get some 2000 grit wet n dry handy,
kerosine, and even use the laundry tub with hot hot soapy water. (I can
heat you all scream now .. noooo ... not water .. pfft .. it's fine!)

1. Do you usual bit and take off the calipers following the manual etc
2. Rip out the pads, and also use the brake lever to push the pistons
out. Many rags n extra bits of cloth are handy here, as you usually end up
putting brake fluid everywhere. Or, if you're lucky just get an air
compressor to blow the pistons out. Remember to have some cloth (and NOT
your hand) in between the opposing pistons when you do this.
3. Clean then up with kero to start with, a tooth brush and some 2000
wet n dry on the spots/pits etc on the pistons or bores.
4. Here's where I usually get some gloves and the hottest water you can
get with some suds etc. It's good to soak them in and washes away all the
kero etc. Also the heat absorbed by the calipers means they'll dry by
themselves when you take them out and rinse them off again. Also,
compressed air is a handy thing to have here.
5. Reassemble with new seals if you can afford it, or if the existing
ones are ok just wack em back in. This is always hard as the tolerances are
quite tight and there's usually quite a bit of bitching going on. Needless
to say I've never attempted it on my 6 piston calipers just 'cause I know
it'd be too much bloody work. Did it on the 4 piston ones though.
6. Enjoy your afternoon by bleeding the brakes, but they'll work sooooo
much better. It's amazing the difference cleaning the pistons/bores and
replacing with fresh fluid makes. Also, I'de be taking the master cyl etc
apart and inspecting/cleaning/replacing seals if they are leaking or
catching etc as well. You'll be amazed by the difference.

Cam
'00 ZX6R

 

bah - another thing to add to my bike to do list

there should so be a day where all motorbike owners meet together and every1
does all their servicing together - wont be so boring and tedious then and
every1 could help every1 else.

wishful thinking

thanks cam

 

hahaha

I'm not in Canberra though, - Sydney

 

Correction ..... fair enough ...

 

Sounds like there is no freeplay between the piston in the master
cylinder and the brake leaver so the brake is not releasing and the
clearance might be affected by the temperature, or you have stirred up
some shit in the brake fluid and it is making the piston in the master
cylinder stick and not come all the way out of the master cylinder.

 

He came second... does this mean Damien from Canberra is a "winner" ?

Nev..
'02 CBR1100XX #2

 

Kinda like when people thought I was Crazy ....

Cam
'00 ZX6R

 

Yep that's me.. I didn't change my name such as to avoid any confusion that
may have arisen

 

I think it may be a tie in the smartarse stakes Nev!

 

The bottom of the reservoir in the master cylinder has 2 holes in it.
One is fairly large, and is where the fluid is pumped into the line
when you squeeze the lever. The other is very small (coincidentally
about the diameter of a single bristle from a wire brush). The
smaller hole is used to allow fluid to seep back into the reservoir
when the pistons are pushed back into the calipers, and if it's
blocked you can get a "ratchet" effect on your brakes.

I've only ever seen this on 20+ year old neglected bikes, but if
you're taking the calipers apart you might as well service the master
cylinder while you're at it.


BTH