breaks/calipers

[grandmasterbo...]

hi i was wondering what to do about my binding front break on my CBR 125 i sprayed it with cleaner before because it was makeing a squeaky noise and the dealer sed it would fix it then it came back and i took it to my mate who said that it was binding as on the 5 min journey from mine to his the front break was extremely hot when i took it back to the dealer i was told that it would cost me about £65 to get it sorted or i could take it of and clean it out and hope that that works

so what would you all recommend take it to them or try to sort it myself?

[steo]

if your ok with the spanners then it's a handy enough fix. you probably shouldn't have sprayed the caliper with cleaner as this could make the seals distort & swell, it's the brake pads that make the squealing noise. take a look at the pads, make sure they're sitting in the caliper properly & that they're not snagged up in the brake pad clip. if they're ok then the piston in the caliper is probably semi seized with dirt & gunge so when you pull in the brake it's not returning into the caliper thus making the brake bind. if you take the piston out then you will lose your fluid unless you use a clamp on the brake hose but you're still going to have to bleed the brakes. you maybe able to get away with cleaning the piston by removing the pads, pumping the brake till the piston is 3/4 way out of the caliper, clean it lightly with a bit wire wool & brake fluid, (you don't want to scratch the piston) & be careful with the seals, clean it off with a cloth. put a bit of brake fluid on the piston & push it back into the caliper. if you use a large G clamp, it's easier.

[Finglonga]

https://img.photobucket.com/albums/v112/finglonga/Finglonga%20Inc/BRAKE.gif


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Andy Sez....
F.Y.Y.F.F.

[Noxious89123]

[steo]

thanks noxious for the pat on the head & the kick up the arse but we're all here to help folks that don't have the experience of working on bikes that you have. i try to make things as simple as possible & could have suggested using oiled wet & dry sandpaper which you didn't specify so i said wire wool (not a brillo pad) which maybe less abrasive on the pistons. your thread is accurate to a certain extent if the poster knows what you're talking about but you probably need to come across in layman's terms for people to understand all your technical jargon. sorry for the rant bobo & don't mean to patronise you as this thread is not helping your cause.

[The Artist]

[steo]

read my last thread again allymoss, i didn't suggest using anything abrasive & unless caliper pistons are now manufactured from candle wax, lightly rubbing with wire wool & brake fluid is not going to take the crome coating off the pistons. i'm done with this particular post as i'm sure the person with the brake problem has all the info they need but i am looking forward to reading what you & the other 'johnny come lately' have to contribute to future posts. hopefully you will start off the replies & not wait to find out what other people's thoughts are before posting a thread.

[Davie_G71]

As has been said - just use brake fluid and some cloth for cleaning the pistons - nothing abraisive in any shape or form if you have any pitting or scratches on the pistons then replace them.

Also when you take the seals out clean all of the crud out from the seal seats, there will be loads caused from oxidisation and general road grime. Spray some brake cleaner into the seat seals after cleaning and this will dislodge all the wee fragments that you have left behind from cleaning, brake cleaner won't damage your seals.

WD40 can be used, but this could damage your seals, but ok if you use a bit of brake cleaner afterwards.

David.
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Suzuki GSXR600 SRAD, 1997 & Kawasaki Z1000, 2003.

[Noxious89123]

[Mr Hammers]

It's also worth checking that the tiny return hole in the master cylinder isn't blocked.

If it is, it means that as the brake gets hot and the fluid expands, it has nowhere to go except to push out the calipers, instead of back into the master cylinder.

An easy visual check is to remove the reservoir cover, and when pulling the brake on and off to look for a small disturbance in the fluid.

Anyway, good luck
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A Guide To Powerbands

[TUG]

I can tell you how to over haul your brakes so they're like new if your good enough with the spanners?
You would need :-
Bottle of brake fluid
Brake oil seal
Brake Dust seal
A pick at 45-90 degree angle or bent screw driver
Pair of mole grips or pliers
Vice
Red grease.

If memory serves me the front brake on the CBR125 is a 1 pot slider?
You need to take your brake pads out, take the caliper off, pump the lever untill the piston is on its last stroke or gets forced out, now depending on how badly your seals have swollen, you should be able to wiggle the piston out with the caliper in hand.

Remove both seals, get your pick or screw driver thats bent and scrape out all of the white corrosion and make sure you get all of it out.
To put the new seals in takes a bit of fiddling so be patient, you should have some red grease at hand to apply to the seals and piston, When you have seated the seals correctly you can now insert the piston and it should slide in after an initial bit of posistioning and gentle persuasion.

Once the piston is back in the caliper you will then need to bleed the brake, refit the pads and caliper to the fork leg, you will need a brake bleeding kit or clear tube and empty bottle.
To bleed your brake get an 8mm spanner, put the clear tube on after the spanner, hold the brake lever in with a full master cylinder and undo the bleed nipple, then pump away until the master cylinder gets low at this point you need to hold the lever in and tighten the bleed nipple, top up the fluid again and then repeat untill you cant see anymore air bubbles in the clear tube.
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Haz ER-5, innit!

[Noxious89123]

Just to add; brake fluid could also be used to lube the seals and pistons for reassembly, if you haven't got any red rubber grease.


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'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[TUG]

[Noxious89123]

What would happen if some of the grease got on the inside of the seals, so it was trapped inside the hydraulic system?

I would have also suggested silicone grease (wonderful stuff, never sets or hardens) but can't imagine it would be good if it got into the brake fluid.
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'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[TUG]

[TUG]

Ow you'll need to squeeze the brake pipe to gain pressure, clamp the pipe, then hold, pump the brake, keep held and release the pipe you will hear all the air inside gettin moved repeat this till you have pressure then bleed.
I did a rear caliper on a DT125 today like brand new now.
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Haz ER-5, innit!

[StevRS]

If you're not looking to change the fluid, which can be fiddly if you're new to it (and you certainly don't want to balls it up!!) then you can take the brake fluid reservoir cap off and this will allow you to push the piston back (a spanner across he piston with a thumb at either end will move it back - it might be quite firm) to get the pads back in and over the disk after cleaning.

At this point you can rough up the pads and disk surface if you like to remove scoring or corrosion as well as check wear, clean up any brake dust (don't inhale it) with brake dust agressor and a cloth.
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MV Agusta Brutale 800 RR, Unfinished 1978 XS250

[Noxious89123]

Why remove the res cap to push the pistons back in?

You can do all of that stuff you just said, without removing the res cap...
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'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[TUG]

[StevRS]

[the grim reaper]

[Noxious89123]

So many thing I'd like to do, but need to save £££ for a car, and I'll never get there if I keep blowing money on my bike....

Things to add to the wish list;
Braided Lines
New brake pads
New brake fluid

Is i easy to get the old seals out without fubar'ing them, or will they likely need replacing if removed?
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'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[TUG]