Brakes dragging/sticking

[motorbyclist]

took front wheel to my NC30 into cycletreads for new bearings, got back home and wheel spins forever. attach & pump brakes and wheel is now hard to turn, whereas before it was fine.

lever felt rock solid, before it was a bit squishy.

pulled brakes off, found both brakes were dragging, pushed pistons back incase they were sticking, still have problem.

did 550km this weekend and they're still doing it.

i can feel them loading the chassis/suspension and loading the motor on the motorway, the discs are always quite warm, and pads must be getting mauled. this is less than ideal what with the weather lately and petrol prices


so, any ideas to remedy this before the weekend?:sweatdrop

no i haven't bled the brakes for some time, planning to do that shortly. full seal kit/rebuild would be nice to do but i have a coro loop to attend on sunday!


cheers

(for those that don't know, these are standard NC30 twin 4pot each hydraulic calipers on some very heavily crossdrilled discs without much scoring. use same master cylinder joined to two seperate lines. pads have plenty of life)

EDIT: the boot around the "plunger" is and always has been broken

[cowboyz]

get some brake clean and pull everything to bits and clean it out. replace fluids. If you have brake issues it probably best to deal with it and skip corogp for the weekend. I dont think they are closing the road in the next few weeks.

[awayatc]

broken boot around plunger doesn't sound to good...it will allow grime buildup around plunger, and thus make it harder for plunger to retreat....
Good luck

[Katman]

Rather pointless just cleaning up the pistons because that's not likely to be where the problem lies. Once the pistons are out the seals need to be removed from the calipers and the layer of shit that builds up on the back side of the seal and the grooves the seals locate in needs to be scraped clean. The problem is caused by the layer of shit forcing the seals into a tighter contact with the piston and therefore not allowing the piston to retract properly.

Here's your answer.

[more_fasterer]

Had the same problem a couple of months ago. Bought a master cylinder rebuild kit from Swindlespot for ~$100 & the problem went away. My plunger boot was broken too.

[vifferman]

Just a thought - are you sure the wheel spacers are properly installed, and that the front axle, calipers, etc are all installed straight?
It seems a bit odd that it was fine before, and now it's not; the only thing that's changed is new wheel bearings and the wheel's been off and back on again.

[mouldy]

Were the brakes releasing before you took the wheel out ? Sometimes when you do the front axle up on Hondas the left hand fork leg gets dragged in as you do up the bolt , check that the line on the left hand side of your axle lines up wirth the fork leg , if not loosen off all your pinch bolts and pump the font end up and down to centre your wheel properly as this can make your brakes drag .

[Katman]

Another thing to check is - remove the reservoir from the master cylinder body and you'll see two holes that the fluid passes through. The one closest to the brake hose is very small and can easily become blocked. This hole allows fluid to bleed back into the brake lines when the lever is released.

[imdying]

As always, a lot of things that basic maintenance covers are being touted as things to look at, and rightly so... so the real lesson is, do your basic maintenance dammit!!!!

[vifferman]

... loosen off all your pinch bolts and pump the font end up and down to centre your wheel properly ...
Er... just loosen one side at a time, or just some of them.

[motorbyclist]

Just a thought - are you sure the wheel spacers are properly installed, and that the front axle, calipers, etc are all installed straight?
It seems a bit odd that it was fine before, and now it's not; the only thing that's changed is new wheel bearings and the wheel's been off and back on again.

right, will look at that


Had the same problem a couple of months ago. Bought a master cylinder rebuild kit from Swindlespot for ~$100 & the problem went away. My plunger boot was broken too.

gah, weapon of last resort


Here's your answer.

as above (yes i did search the forum first, and read that very post), but am looking for simple solution before i bury $100 in seals i don't need (yet) and may not receive before sunday

particularly as i don't have the $100 AND petrol money:(


As always, a lot of things that basic maintenance covers are being touted as things to look at, and rightly so... so the real lesson is, do your basic maintenance dammit!!!!

guilty as charged, just left the brakes to their own devices and kept putting off that fluid change. just been flat out with uni/work/smc lately and this coro loop will (was to) be the first real ride on any of my bikes since february.....


cheers for the advice guys

[Max Preload]

did 550km this weekend and they're still doing it.

Ya don't say... I can't understand why they haven't fixed themselves, the lazy bastards! <_<


i can feel them loading the chassis/suspension and loading the motor on the motorway, the discs are always quite warm, and pads must be getting mauled.

...full seal kit/rebuild would be nice to do but i have a coro loop to attend on sunday!

Good to see your priorities are in order! Dragging brakes, dragging schmakes! :2thumbsup


EDIT: the boot around the "plunger" is and always has been broken

Do you think they came out of the factory like that?

The boot around the master cylinder piston is to stop dirt and water getting in to attack the back of the master cylinder piston seal - like the dust lip on an oil seal. If the master cylinder seal gets damaged from behind :buggerd: it'll fail prematurely and possibly spectacularly.

I personally think KATMAN's spot on about the seal (I presume he's meaning the dust seals, not the piston seals, although I've seen both corroded grooves) and the grooves inside the caliper being clogged with shit too.

Also, what KATMAN states about the small hole in the reservoir is critical - if that's blocked, air can be drawn in, past the master cylinder piston seal, when the lever is released because the low pressure (vacuum) will not be broken.

[motorbyclist]

Ya don't say... I can't understand why they haven't fixed themselves, the lazy bastards! <_<

lol that's what i said too! (thought with a bit of riding in the hail they might magically free up - provided they aren't backing past a certain point due to corrosion/dirt as opposed to backing off at all due to valves, wearing out the pads a bit over several hundy kms may have fixed it



Good to see your priorities are in order! Dragging brakes, dragging schmakes! :2thumbsup

well i'm only commuting/cruising on them..... it's not like they don't work, quite the opposite infact.

if they weren't working i'd be riding my brother's FXR, i'm not a complete idiot



Do you think they came out of the factory like that?

The boot around the master cylinder piston is to stop dirt and water getting in to attack the back of the master cylinder piston seal - like the dust lip on an oil seal. If the master cylinder seal gets damaged from behind :buggerd: it'll fail prematurely and possibly spectacularly.

I personally think KATMAN's spot on about the seal (I presume he's meaning the dust seals, not the piston seals, although I've seen both corroded grooves) and the grooves inside the caliper being clogged with shit too.

Also, what KATMAN states about the small hole in the reservoir is critical - if that's blocked air, can be drawn in past the master cylinder piston seal when the lever is released because the low pressure (vacuum) will not be broken.

right, now i know what it actually does i can better appreciate why this matters that it's been split for atleast 18 months...



still going to try re-aligning the front axle. it just seems so random the way the problem has arisen, but by the same token you'd think even if the wheel was out the brakes would equalise around the discs anyway....

[imdying]

guilty as charged, just left the brakes to their own devices and kept putting off that fluid change. just been flat out with uni/work/smc lately and this coro loop will (was to) be the first real ride on any of my bikes since february.....Don't worry nobody does it... first thing you should do when buying a second hand bike is rebuild the calipers. A good thing to do is attack the calipers (concentrating on the pistons) with a toothbrush and hot soapy water at every oil change (half that interval is better, but people have busy lives).

[motorbyclist]

Don't worry nobody does it... first thing you should do when buying a second hand bike is rebuild the calipers. A good thing to do is attack the calipers (concentrating on the pistons) with a toothbrush and hot soapy water at every oil change (half that interval is better, but people have busy lives).

thanks, i'll keep that in mind


anyone got advice on doing this seal kit when i buy it? how would one go about removing all 8 pistons?

[motorbyclist]

undo the pins that the pads slide on

take your calipers off

clean the pistons, sand the pins lightly(to clean them not more!)
put everythign back in the same places, making sure that the pads contact the same part of the disk that they were beforehand.

with soapy toothbrush i shall do this later tonight, along with checking alignment

[Chrislost]

with soapy toothbrush i shall do this later tonight, along with checking alignment

dont drop that soap aye!

*muttering* dam honder riders

[kiwi cowboy]

dont drop that soap aye!

*muttering* dam honder riders


:Oi::angry2::angry2 NUFF BOUT ONDA RIDERS OR YOU GET DA:innocent::bash:

[FROSTY]

Dude think this through.
Brakes were all good-no issues
Wheel taken out -nothin else disturbed
Wheel put back in -brakes suddenly shite

Conclusions I'd draw are A assembily process you used was wrong
Mouldy suggested one possibility -leg over too far -and also pspacers wrong
If not
Try removin one caliper and see how the wheel spins--then refit it and remove the other caliper--at least then the issue is isolated to one side


B replacing the bearings might mean that the disk no longer "slaps" the pads back -I doubt it but if thats the case then piston clean up / fresh fluid time and all will be back to spongyness

[motorbyclist]

Dude think this through.
Brakes were all good-no issues
Wheel taken out -nothin else disturbed
Wheel put back in -brakes suddenly shite

Conclusions I'd draw are A assembily process you used was wrong
Mouldy suggested one possibility -leg over too far -and also pspacers wrong
If not
Try removin one caliper and see how the wheel spins--then refit it and remove the other caliper--at least then the issue is isolated to one side


B replacing the bearings might mean that the disk no longer "slaps" the pads back -I doubt it but if thats the case then piston clean up / fresh fluid time and all will be back to spongyness

spacers only fit one way around otherwise the right disc hits the fork

last week when problem occured I tried removing one caliper and drag was lessened, remove both and spins fine. push pistons a fair way back, hoping any shit in the valving would be forced out, put back on, pumped back up and problem remains

old bearings were only just getting grumbly, no play had developed, but i think the right disc did make a chafing noise like it wasn't straight

maybe if the bearings aren't installed properly it would change things, but i always assumed the pressures equalise so provided it's straight the disc can sit anywhere and not have troubles till a piston pops out

so will try for leg, tomorrow night, and see if it works.
then bleed & clean brakes anyway as it needs doing

[motorbyclist]

right, so today when i jacked the bike up the front wheel seemed to have finally begun to magically fix itself:D (done 800km since wheel bearings installed)

but i thought i'd look at 'fixing' it anyway. re-fitted axle and sure enough i had put it thru just too far by just a smidgeon (not quite 1 mm). at this point i was back to square one as wheel hardly moved.
removed right caliper and left one still dragged but wheel easier to turn than before. swapped calipers and same result

so now i had the left one loose, i went about removing pads and cleaning each piston individually. they all had a fair bit of crap on them, some of which i couldn't move, but they all were clean past a certain point.

remove right caliper (so no brakes) and wheel spins fine - right disc has the slightest of wavers to it, which i already had detected by sound after my little oopsie in movember, but never gave any physical feedback under braking.

all good, reattach left caliper, slightly more drag than expected but bearable:).

right caliper cleaning same as before but couldn't eject one of the bigger pistons, ended up putting tools in caliper to hold the other 3 still while the sticky piston was free, after a couple of pumps the lever was really pushing back, and then with a crack the lever came back to the bar as the piston moved forward. cleaned up piston best i could and it was farking difficult to push back in. reattach, wheel now hard to spin, just like it was before when problem first arised.

so, another 800km and hopefully it'll come right again:whistle:

actually, after a 50km test in the rain it's not too bad right now, but right caliper is definitely the problem (can tell as it jams more when disc waver pushes against stuck piston)


so i'll make an order for a seal kit and do it properly asap

cheers guys

(PS, where can i get some grease to protect the new seals, and some grease to keep the locking pins from seizing in there? i gather that "normal" grease would not suit)

[imdying]

Just the act of freeing up the pistons themselves will be worth while :yes:

There's no grease that will protect the seals, that's why regular maintenance is important. You can get rubber grease from a brake show to aid assembly, but in reality brake fluid will do that fine. Whilst you're at the brake shop, get a little brake grease (something like Wurth Brake Paste, Girling Brake Grease, or Coppaslip) and use that on your locking pin threads.

[vifferman]

Dude think this through.
Brakes were all good-no issues
Wheel taken out -nothin else disturbed
Wheel put back in -brakes suddenly shite
Hmmmm... that sounds familiar.
I thought no-one read the shite I post...

[FROSTY]

Brakes+ grease/oil = bad

Mate if ya got the time/inclination bring the beast to my place tomorrow.
I suspect Ill be able to clean those pistons up just a "tadd" more'n you did.
Hey did ya try spinning the axle?
Wonder if its got a lil bend in it

[motorbyclist]

Brakes+ grease/oil = bad

Mate if ya got the time/inclination bring the beast to my place tomorrow.
I suspect Ill be able to clean those pistons up just a "tadd" more'n you did.
Hey did ya try spinning the axle?
Wonder if its got a lil bend in it

yeah, i was pretty lax on the cleaning - didn't want to use anything harsher than a soft brass wirebrush and there was some stuff that simply wouldn't shift

brakes have made a definite improvement since before cleaning them

slight drag, but it's basically smooth so not a (major) hazard under emergency braking


will pop by if i can

[motorbyclist]

Mate if ya got the time/inclination bring the beast to my place tomorrow.


seals will be a while it seems

offer still stands for a weekday?

[FROSTY]

sorry dude workshop is used weekdays