caliper rebuild

[stranger12]

Hi All,

I thought, I clean my front calipers with washing liquid and check the condition of the brake pads.

I know r6 has a fixed caliper so when opened , i tested the caliper to ensure it does not have a sticky piston . I did press the brake lever and one or two of the pistons were popping out quicker than the other 1-2 .
is that what is known as sticky piston ? if so what can cause sticky piston , the seals?

now I have taken both calipers out and when one of pistons popped(pressing the brake lever to many times) I saw some white stuff sorted of sticky and powder shape inside the bore, what can it be ?

If I want to pop all 4 and then clean the caliper, can I use water and let it dry out .

My other main problem is , popping all pistons out as after one of it has popped the air leaks so can not get the other 3 out.

I understand lots of questions have been asked but do appreciate your help.

thanks
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SV650 Red
R6 Red

[ws4936]

[Rogue_Shadow]

The white stuff is likely road salt, it builds up ontop of the "dust seal" and can very slowly get underneath the dust seal.
When this happens the piston will not full return and given time it can cause brake binding.

Don't use water to clean out your brake callipers once you have removed the pistons, it will contaminate the brake system

Ideally you should of slowly pumped the brakes with something blocking the path of the pistons like a piece of wood. Once all the pistons crush into the piece of wood, remove it and find something slimmer and pump the pistons against it again.
Rinse & repeat until all pistons are mm away from popping out

However

As you've broken the pressure seal, you'll need to VERY VERY carefully pull the pistons out somehow. I've never had much luck holding a piston in once I've popped it out

Head over to youtube & search for "delboy's garage caliper rebuild" to give you a better idea of what needs to be done.
You may of wanted to just clean the brake calipers, but now the pistons are out you might as well do a rebuild

[stranger12]

changing the seals ?

where do you normally get your items from ? wemoto ?
____________________
SV650 Red
R6 Red

[ws4936]

Are the seals bad? If they seem to have kept they're shape, clean them up and reuse them, otherwise, yes....wemoto.
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If everything seems under control, you're just not going fast enough.

[ws4936]

Before putting the seals back in, make sure the calliper is clean from crud in the grove where the seals go. Get a firm toothbrush and start scrubbing.
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If everything seems under control, you're just not going fast enough.

[stranger12]

wouldn't wire brush damage the piston bore thus the motion of the piston back and forth (getting stuck)?

if seals are not bad, what can cause sticky piston ?

was my situation described above related to sticky piston ?
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SV650 Red
R6 Red

[ws4936]

[janner_10]

At this stage I would remove from the bike and clean thoroughly. A set of new seals is cheap enough and usually available off the shelf at a dealers. Gives you a chance to inspect the pistons too. Once off, you can clean the calipers in warm soapy water or in a ultrasonic bath - then just pop into an oven on low heat to dry thoroughly.

A bent paper clip will get right into the seal groove and get rid of the salt. All in all its a fairly easy job. Also gives you a chance to change the fluid.

Search You Tube - literally hundreds of vids detailing brakes - a lot are R6 specific.

You don't need any fancy tool to bleed the brakes, just a length of tube into a old jug and an 8mm spanner IIRC.
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Yamaha FZS600 (Now gone to heaven) > CBR600F4i (SOLD) > '99 YZF-R1

[stranger12]

Two questions,
Was the issue i had whereby one/two of the pistons moved out quicker a sign of a sticky piston ? Are they (all 4) not meant to move together.
When i initially tested it none of the pistons popped (didn't let it) bit still few of the pistons seemed not to move and only moved when i put a peice of wood in between and the other two popped most of the way and hot the wood .

That then made them move. So is that normal or is it sticky piston ?
What will cause a sticky piston ? Swallon seals or rusted piston ?



Now regarding the salt and cleaning of it, can i use brake cleaner in the system?
____________________
SV650 Red
R6 Red

[Hetzer]

I've used hooked tweezers to get the crud out of the grooves; it's not salt, it's oxidised aluminium and very hard to shift with anything that's not metal.
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"There's the horizon! Ride hard, ride fast and cut down all who stand in your way!"

[stirlinggaz]

hi,
like hetzer says, its corrosion, not salt & i remove it with thinners/acetone or brake cleaner (whatevers lying around) & then clean seal groove with dremel with the wee brass brush atachment,
cheers,
GAZ

ps : i've always fancied an ultrasonic cleaner, so if anyones cleaned up a cruddy caliper with one, please post results

[Vincent]

[stirlinggaz]

Vincent wrote:

I came to the conclusion you'd need to spend a couple of hundred knicker to get a good used one.

sounds a bit expensive to me...but hoped i could use it for carb cleaning etc,
oh well i better start saving,
cheers,
GAZ

[Coxyzxr]

Not everyone's aware but the piston seals are usually ever so slightly tapered to give the best possible seal when the piston moves outwards.

Watch out for this when installing the new ones.
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**WAS FITTED "WRONG WAY ROUND" !** CANT ACCOUNT FOR THE STUPID !

[sidewinder]

Don't forget to use some red rubber grease as well

[stranger12]

red rubber grease on the seals ?
Wouldn't silicon be better ?

I am no good with chemicals and hence why I am asking ,
I use paraffin to clean the chain, exhuast etc . I guess I could use that to clean the caliper ?
I know paraffin or wd40 must not touch the pads, but guess they can be used to clean the caliper internal parts.
Or even carb cleaner


so with the brush , I think it can't be wire brush can it ?
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SV650 Red
R6 Red

[Major Doss]

Red rubber grease is silicone. You can get it in little tiny pots that make gold bars seem cheap, or a big tub that will last for a couple years for a few sovs. Coxyzxr is spot on, some fluid seals can be tapered, ensure the narrow edge of the taper is on the fluid side ( just done mine, they weren't, but then it is only a shit bike!). The dust seals are generally square, but as they are usually of a smaller width, they will be easily distinguishable. Keep a careful record as you strip and you won't go wrong. Take photos if it helps. Make sure you do not go wrong. I do find caliper rebuilds perversely enjoyable. Except for MK1 Hinckleys, what a bugger for some reason!
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Antisocial phucker.

[Pigeon]

[mentalboy]

And as no-one else has done the honours!
You'll find that the pistons will usually move out at different speeds when there is no resistance on them however if you were to put your fingers on the fastest moving one then apply light pressure whilst squeezing the brake lever the others should move out further.

DO NOT DO THAT if you're at all unsure if one of the pistons is stuck or you are unable to control the brake lever yourself or you will squish your pinkies!!!

Resistance is not caused by a swollen seal but by the crud mentioned by others that builds up in the seal groove thus jamming the seal against the piston and the reason everyone says clean the groove.
There are a lot of fans of red rubber grease around but equally as many (I should think) who just use brake fluid as a seal lube.

Going back to the ultrasound machine a cheapo one will do the trick if you've got access to an airline to blow the rubbish out afterwards (and it's also great for popping obstinate pistons out)
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Make mine a Corona.

[Islander]

[Major Doss]

correct. i stand spacktarded.
I thought millers did a silicone version.
edited coz i felt like it.
good luck with the stoppers.
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Antisocial phucker.

[Major Doss]

BTW, has anyone experience of 'splitting' OP's calipers? Do the blue spots just unscrew, or are they a palaver?
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Antisocial phucker.

[janner_10]

From memory you have to have the piston removed first and then screw them in to remove them, plus need a special tool - which isn't that much, just a pain in the bum.
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Yamaha FZS600 (Now gone to heaven) > CBR600F4i (SOLD) > '99 YZF-R1

[stranger12]

Thanks for everyones contribution.

To update i bought the seals for £40 from wemoto and will replace them any way. I am quite aware of how to check and ensure the piston seal is in the groove correctly.

I normally fit it in and move my finger from bottom of the chamber upward and i should feel the edge of the seal and not other way around , am i right?

Re cleaning the white stuff seems as it is not planning to come off . I will do my best to try and remove it using brake cleaner and tooth brush.

Also they way i am going to clean them is by popping one piston out at the time. I think it will almost be impossible to remove all 4 . This is because if I push them all out then there is no space between them to pull them out. I think i will need some sort of pliers designed for this job in order to get all 4 out or a very strong air compressor ( i am currently using the foot pump i have which once one of the pistons is out , the air escape and others won't move)
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SV650 Red
R6 Red