NC30 rear disc removing question.

[Neosophist]

I mean the piston you took out already of course.

It should push in nice and easily, the rubber grease will stop you damaging the seals.

Your master cylinder looks like a chinese shit job, IF it is, then this will probably the be reason it doesnt have enough force to pop the pistons out and you should throw it away and replace it with a proper Honda one.

Push the old piston fully in, either use a clamp or a pair of ring spanners to create a lever action to force it in.

Your starter relay also looks to be floating in mid-air, not in the protective boot that it sits in to stop it vibrating and shorting out against the frame.

[xivlia]

that picture is n old pic, the started relay is intact and in place. ive pushed the old piston all the way in now what do i do? cant do much else. Ricky yes i have the shitty chinese ones. But i think i know why its making that noise in the M/C after i press it. the fluid is trying to get forced into the caliper, and when i let go of the lever the forced fluid is getting pushed back into the M/C macing a bubbling noise so i dont think its actually leaking air.

pip, how was i suppose to know the piston calipers where fucked before i bought the bike?, the owner told me it was the master cylinder which needed swapped over. so i have the right to blame the previous owner all i want, this aint no fault of mine.

[CMSMJ1]

The m/c sounds fucked to me to be fair - either it is bled OK and so would push the fluid nicely and then not breathe in a load of air..or it would push it nicely and then return and keep the air out the system,

On the previous owner stuff...well..yes, but it is yours to sort so no real point blaming them.

[speedy231278]

I've never, ever heard a master cylinder click before. And I'm sure you won't hear a bubbling noise if only fluid is coming back into the reservoir. Look on eBay, and you'll find loads of rear master cylinders for £10-15. Honda seem to use pretty much the same thing on the rear of most bikes of the era of NC30/35s, however with your aftermarket sets presumably coming with one, the mounting points may be a different spacing, so it would be worth measuring the centres and confirming with the seller.

Of course, just to get the piston out, you could always take the front one off and use that, although you'd have more bleeding to do afterwards....

[Neosophist]

that picture is n old pic, the started relay is intact and in place. ive pushed the old piston all the way in now what do i do? cant do much else. Ricky yes i have the shitty chinese ones. But i think i know why its making that noise in the M/C after i press it. the fluid is trying to get forced into the caliper, and when i let go of the lever the forced fluid is getting pushed back into the M/C macing a bubbling noise so i dont think its actually leaking air.

pip, how was i suppose to know the piston calipers where fucked before i bought the bike?, the owner told me it was the master cylinder which needed swapped over. so i have the right to blame the previous owner all i want, this aint no fault of mine.

Fluid does not make a bubbling noise unless air is present to bubble.

Regards to your comment towards pip.

You were not liable to know the pistons were sized unless you stripped the caliper before buying the bike which being fair mostly nobody would do.

HOWEVER.

YOU replaced the master cylinder, YOU failed to check the pistons were sized, YOU took it to the MOT with a non-functioning rear brake.

You can blame whoever you like but that wont fix the problem. Pip seems to be saying what most of us are thinking in that stop blaming the previous owner and fix the damn bike.

Perhaps the previous owner did really think it was the master cylinder, and he sold it to you believing such. His liability ends there. Its your resposibility to check and fix the bike.

Imagine you fix up your NC30 so its running great, sell it on and then within 1 week the new owner has the head-gasket blow. Is it your fault?

It appears the prior owner knew something was wrong, told you what they thought (alebit incorret) and you blame them for your inabiltiy to repair said issue.

I've said it before but log off the internet and find somebody who is expereicned with bikes to show you how to sort the calipers out. They are not some complicated thing. No amount of text on here will beat somebody who knows what they are doing with a spanner in their hand teachign you how to fix the issue.

Once you have the basics down then asking a specfic question is ok but to put it another way, its like asking a chinese guy how to say a specific word. You might get an answer but without knowing the rest of chinese you cant do a lot with it.

[xivlia]

i dont know what to tell you man, the piston wont come out... simple as. i know its not a complicated thing but maybe some of you are over thinking too much. the piston is stuck, i tried to push it out with the M/C when it was FULLY bled, its obviously getting air from the little window or something, the M/C is a crappy chinese make, i only bought it because my previous rear sets gear lever broke when i dropped the bike and i couldnt find OEM or a replacement part for the one i currently had, so the only option was to buy a brand new after market.

and now that the piston is fully pushed IN with a g-clamp there is no way of getting a grip of the piston with mole grips or the likes. i will try the bleeding and pushing the brake pedal method again but i dont see it making any difference from the shitty M/C i have. i am going to try heating up the area to "melt" the seals if you will, like ricky mentioned and see if thatl work, maybe the small expansion of the heated metal might work also.

[Morespeedvicar]

Ok try summats else, push both pistons in and bleed up, pump out goodish one until its half way out, put gclamp on the good piston, get somebody to hold down the rear brake leaver, and wind in the gclamp and see if it'll force out the other piston, that prob makes no sense but i know wat i mean! Good luck! Like i said bike brakes can be a complete twat!
Just another thought, if the rear master cylinder isnt set up well it maynot bleed right to start with.
Cheers
Ian

[xivlia]

yes i know what you mean and i tried that yesterday, and i will try it again tonight. i hope itl work, im sure the seals have been weakened by now on the stuck piston. surely it will come out.

[speedy231278]

OK, here's a pie in the sky idea. You say you have a mate that can weld, and you've also said you've attacked the piston with mole grips. Given this and how stuck it is, there's a fairly good chance it's buggered anyway. So, how about getting a hefty nut, washer and bolt, and a strong piece of flat bar. Weld the head of the bolt to the bottom of the inside of the piston. Drill a hole in the flat bar big enough for the bolt thread to go through. Put the bar across the caliper body with the bolt thread going through the hole, then put the washer and nut on the end. Then try winding the nut up and see if it pulls the piston out. However, I'm not sure if the shape of the caliper body is suited to this, and the bar might not just get pulled over and slip off. Also, if it's really, really stuck, I don't know how much effort might start to distort the body of the caliper.... Maybe weld the thread end of the bolt to the piston, and try and turn it using a spanner or ratchet instead?

[xivlia]

i could do that, but honestly its much more hassle, i could just buy a second hand caliper that actually has working pistons, and that actually has pistons that come out. if you think about it, either way im gonna have to buy new piston and seal kit. i saw a caliper for 20 quid, so it aint too much. if i cant get it out tonight im going to try the heating method with my dads jewellery torch to melt the seals and if that doesnt work then, i will take it to my local garage and if not then time to buy a new caliper.