NC24 Brake Problem - Any suggestions

[queenmonkey]

I'm now completely frustrated with my NC24. The bike stood for 18 months before i brought it so the brakes were seized and the front wheel would only turn with great force. I stripped the calipers out. Pistons looked a bit manky and the dust seals frayey. I bulked at the price of pistons and seals so brought a supposedly good set of brakes off E..y. Fitted those and the wheels still dragging.

I've had these calipers on and off ten times now. I'm awash with fluid and frustated to hell. I've grased up the sliding mechanism and have brought new seals off B..y. I fitted those - all the dust seals split - they seem too small! The main seals don't seem much better.

I've cleaned up the grooves and greased the sliders. I've also selected the best four pistons (out of the eight i have ) and polished them up on a polishing machine.and am now wondering if the fault is with the master cylinder? I can't keep throwing money at this bike and only want to get it through it's mot (failed on the binding brake) as it's on the small side for me.

Am i missing something? Is it just a coincidence that the second set of calipers are sticking or is the problem elsewhere - ie the master cylinder? Are the seals for the NC21 the same as the NC24 (the ones i brought off E..y were listed as fitting both).

Advice would be really appreciated QM

[CMSMJ1]

make sure you are not overfilling the reservoir...

[Cammo]

I hear ya! Whenever I've had sticking brake piston issues it's been the master cylinder to blame.

Edit: Drain the fluid from the lines and check whether the master cylinder piston moves freely in and out at all times when pushed in with the lever. If it's dodgy it will usually return slowly or will perform differently at times. Check it many times with the lever action.

Unfortunately without a thorough overhaul of the brake system (which can cost quite a bit depending on parts you need) it's very difficult to diagnose the source of your problems over the net.

It's not much fun buying parts hoping that it will fix your problem only to find out that it doesn't at the end of the day.

I recently bought a brand spankers nissin master cylinder off yahoo japan (about 75 quid) to try and fix the sticking caliper issues I had. I was sick of wasting money on used parts and rebuild kits.

Buy used brake system parts at your risk!

[Neosophist]

For all the money you've spent you probably could have brought a full set of proper honda seals for £40.00

You need to strip and clean them properly and do it all in one go as otherwise it's just false economy and a waste of money.

The pistons are usually ok as there metal capped plastic.

http://www.jacksons-lair.co.uk/caliper.html" onclick="window.open(this.href);return false;

Have a look there

[queenmonkey]

Hi, thanks for the comments. I have now replaced the master cylinder and it seems to have made liitle difference. i have, however, defined the problem being with the left hand caliper (i removed it and the wheel moves freely with the right hand still connected). I fitted the left caliper. If i wack it with a rubber mallet (very carthartic) the wheel moves freely after applying the brake! Now some might think that's (rubber mallet wacking) because i'm moving the piston within the caliper. However, i 'm now wondering if my problem is with how the left caliper fixes to the forks? The second and bottom fixing is to the anti dive mechanism. Does the screw need to be located to the end of it's thread or tightened to the point where it is flush with the mounting.

Any positive suggestions would be welcomed.
QM

[Neosophist]

Did you read my link?

if the pistons arn't sized (which is unusual on these as their plastic) you'll probably find the calipers sized on the sliders.

I wrote up a full description of how they work and what goes wrong with them.

[queenmonkey]

Hi, yes I did read the link - it was very useful, thanks, and it's largely what I followed (although on the budget route). It's still sticking and i'm becoming more frustrated so i'm going to put it to the back of the garage for the week and go back to it in a more positive mind.
QM

[Neosophist]

If your calipers are going on then not releasing theres only a couple of points of failure..

*Pistons Sticking.
*Sliders Sticking.
*Caliper assembled incorrectly.
*Vaccum Lock / Sticking Master Cylinder.

Doing a partial job on the brakes is a waste of money.. if their that bad that something siezed, the rest of the components are proably not far beind.. as you can see in one the pictures I put on my site, the old boot seal had swelled up to double its original size due to incorrect grease and fork oil contamination.

Are your sliders clean, brake fluid lines not blocked up?

If it's just the one side thats sticking its likely the caliper is sized, not assembled properly, somethings in the way. Where abouts are you?