Front and rear caliper rebuild

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swindo221991
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Front and rear caliper rebuild

Post by swindo221991 » Thu Mar 03, 2016 8:51 pm

Hi all

After 3 years of being sat in a garage I'm going to drain all the brake fluid out and replace.

I'd also like to take both calipers off and rebuild - is this an easy task (I can deal with basic mechanics - carb cleaning etc) or one for a shop?

Does anyone have a guide on how to do this, staring from removing calipers from bike to replacing seals?

Thanks
Pete

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banner001
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Re: Front and rear caliper rebuild

Post by banner001 » Thu Mar 03, 2016 10:39 pm

Remove the 2 screws holding the caliper to the fork leg, then remove the pads and put in a bit of metal or wood...you want to pump out all the pistons an even amount until they almost fall out, once one pops out you lose oil pressure to the other 3. Then you need some soft jaw clamps and remove the other 3 pistons from the caliper. The caliper can be split by undoing the 4 bolts holding the half's together before this to make removing the pistons easier.

Then it's a case of prying out the old seals with a curved pick, cleaning out the seal grooves with a brass wire wheel on a dremmel, cleaning out the crap from the calipers making sure to clean all the small oil ways.

I would take this opportunity to use new internal seals, new bleed nipples and new banjo bolts, copper washers and braided hoses.

Then use red rubber grease and new oil and dust seals in your clean callipers, smear a bit of red rubber grease on your pistons (replace any that are pitted or missing bits of the ceramic cap), rebuild the callipers and reverse bleed.
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Re: Front and rear caliper rebuild

Post by banner001 » Thu Mar 03, 2016 10:40 pm

Also take the opportunity to replace the pads for new, along with the pad retaining pin if its worn groves into itself, and maybe the disks if your feeling plush!
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swindo221991
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Re: Front and rear caliper rebuild

Post by swindo221991 » Fri Mar 04, 2016 12:49 pm

Thanks Banner001 for your replies.

At which point do you empty the lines of the fluid? After the pistons have 'popped' out?

I already have braided hoses on my bike. Do braided hoses ever need changing?

I take it I need to remove the wheel to gain enough access to the callipers?

One last thing 'for now ' if I empty the hoses/ calliper of the brake fluid, is it ok to leave them without any brake fluid in them for a number of weeks (ill be rebuild the callipers intermittently during the evenings)? or do they ideally need to have fluid in all the time/ left without fluid for as little time as poss?

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Re: Front and rear caliper rebuild

Post by banner001 » Fri Mar 04, 2016 1:30 pm

you need to pump out all the pistons from one set of calipers as far as they will go, then do the other side, then you can remove the calipers and drain the lines. this way you only need a set of soft jaw pliers to remove the pistons, if you leave them fully pushed all the way in you will need to use an air line to remove them and that can be dangerous if done incorrectly.

as for the lines they can be dry for a while, but dont go leaving them for months like that. braided hoses deteriorate their rubber liners the same as all other lines, if they are pretty new keep them, if they are 20 years old i would replace them.

you dont need to remove the front wheel to remove the calipers, if you have already removed the front wheel slide the spindle back through the forks so the bottoms dont keep turning on you.

after one of your pistons has popped out the system will drain and drain pretty fast so do that bit over a bucket and try and not get brake fluid over your plastics or wheels.
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richyrd5
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Re: Front and rear caliper rebuild

Post by richyrd5 » Fri Mar 04, 2016 1:54 pm

Just to add..when you have got one set of pistons out as far as they go.you will have to put a pad or peice of wood between them so they don't pop out while your doing other caliper...this can be fiddly....what i do is get 4 out at least half way on each caliper then split them in half and then soft jaw grips on the pistons and twist them out.....if you find one or more is tight then push it in and out with loads of wd40(seals are being replaced) or brake fluid to lossen it..they can then be pulled out easily when calipers are split..hth.. winks

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Re: Front and rear caliper rebuild

Post by masterofinsanity » Fri Mar 04, 2016 11:01 pm

a duplo brick comes in very handy at this point :-)
Don't forget people there is more to the zxr400 than this forum... check out www.zxrworld.co.uk also.

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