NC30 rear disc removing question.

Post by **porndoguk** » Mon Dec 17, 2012 10:25 pm

alexwitham wrote:FYI

I did not manage to get the disc fitted without removing the hub.

Now im confussed?

viewtopic.php?f=24&t=39138&hilit=nc30+r ... c&start=10

arsey30 · Post by **arsey30** » Mon Dec 17, 2012 10:45 pm

bikemonkey wrote: I got my dad to sit on my bike with it in 6th gear, front and rear brakes held on while I used my 2 and half foot breaker bar on it.....

First gear is best, engine turns over too easy in 6th
I find 3/4"drive socket and bar better as it flexes less when I use 3 feet of pipe on it.

xivlia · Post by **xivlia** » Mon Dec 17, 2012 11:39 pm

il remove it somehow, it surely cant be THAT much tighter than the rear wheel nut?

Post by **porndoguk** » Mon Dec 17, 2012 11:54 pm

xivlia wrote:il remove it somehow, it surely cant be THAT much tighter than the rear wheel nut?

Oh i can mate, be prepared for skinned knuckles and blood

xivlia · Post by **xivlia** » Mon Dec 17, 2012 11:58 pm

dayum!. quick question.... rick o sells one piston for 16 quid, id need two pistons for my rear caliper to overhaul. is it not better, cheaper hassle free to just buying a used second hand one?

Post by **Drunkn Munky** » Mon Dec 17, 2012 11:59 pm

xivlia wrote:il remove it somehow, it surely cant be THAT much tighter than the rear wheel nut?

don't forget to torque it back up!

Post by **Drunkn Munky** » Tue Dec 18, 2012 12:01 am

xivlia wrote:dayum!. quick question.... rick o sells one piston for 16 quid, id need two pistons for my rear caliper to overhaul. is it not better, cheaper hassle free to just buying a used second hand one?

Depends how good the 2nd hand one is. Are your pistons shot then?

xivlia · Post by **xivlia** » Tue Dec 18, 2012 12:05 am

well. they dont seem to move in and out enough, it feels like jammed. tried pushing them back in with a screwdriver but itl only move about 1-2mm

Post by **NGneer** » Tue Dec 18, 2012 8:08 am

Earsan - don't rush to buy things you may well not need.

Strip the calippers by all means but IMHO about 90% of the time all that is needed is a bloody good clean up of the bores, seal grooves, some new seals and a good clean up of the pistons. I am guessing it is years of crap between the seals, bodies and also on the sides of the pistons which are stopping them working properly.

Remember to pump the pistons out as far as you can before disconecting the calipers from the break lines so you can pull them out other wise you will (a) need to get something like this (http://compare.ebay.co.uk/like/40029535 ... pla&crdt=0) or you will (b) potentialy try and get all medieval on them with a set of mole grips or alike and then bugger them up getting them out.

Have a look here (http://www.youtube.com/watch?v=gp_dNJpsswk) for an excelent you tube guide put together by one of the old skool bredrin from on here. This might be the front calipers - but the principle is exactly the same for the rear. Worth watching a couple of time so you really understand the process.

REMEMBER - these are your brakes, they are important, get the right tools, take it steady and do a proper job!

You will be fine....

pip · Post by **pip** » Tue Dec 18, 2012 8:19 am

xivlia wrote:well. they dont seem to move in and out enough, it feels like jammed. tried pushing them back in with a screwdriver but itl only move about 1-2mm

When the hub nut is slack (you'll need the rear brake to help "hold" it), remove the caliper (slacken & tighten the bleed nipple first) & gently pump the brake pedal to push the pistons out.
Invariably only one will move, stop it from popping out by wedging it with a piece of wood etc so the other piston moves.
Pump the pedal & bring them out equally, you will get to a point when they nearly touch the part of the caliper with the cutouts (there for piston removal/assembly), the pistons will go slack & wobbly & should be easy to remove by hand.

You will need to keep topping up the brake fluid.

If 1 piston falls out when the other is still securely in the caliper, you will have lost brake pressure & it'll be difficult to remove, so go easy & bring them out equally.

Any pitting & the pistons are scrap, I think wemoto does ss piston kits, you will often get a scum line around the piston - this can be gently removed by a soft abrasive (i use an old/soft greenie pan scourer (new ones are too abrasive)) try not to remove the goldy coloured coating, if there are no deep scores, pitting or other damage the piston is good to reuse.
Get a fine tooth pick etc & remove the piston seals & thoroughly clean the seal recess, I find a 90* engineers pick ideal for removing the build up of corrosion, you may have to be quite firm removing it DON'T gouge/score the cylinder bore or seal recess.

Thoroughly clean inside the caliper & dry

Upon reassembly, moisten the seals in brake fluid & re insert in their correct orientation ( i normally smear a bit of red rubber grease into the seal recess 1st) when the seals are correctly in place, moisten the piston in brake fluid & insert, gently rock to get it square in the bore & past the 1st seal.
It should slide smoothly & easily into the caliper with finger pressure. If not something is wrong. Forcing it/getting annoyed won't work, remove & inspect.
Slacken the bleed nipple when installing the 2nd piston, when done, bleed the system

Good luck, Phil

NC30 rear disc removing question.

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