NC30 front brake binding

[bikemonkey]

Just changed my front brake hoses for some braided ones as one of the originals had been worn down so I could see the thread at one point on the line.

Bled the brakes the traditional way and got a good solid lever pressure, only thing is the pads are binding to the front discs and wont loosen off.

Any advice before I get stung at the local bike place?

[CMSMJ1]

You'll be cleaning the calipers, pistons and the shit out from behind the dust seals first I reckon! Don't be getting stung for a basic fix that you can do yourself..

[bikemonkey]

Thanks, any replacement seals or anything that I'll need?

[Neosophist]

As Mark has mentioned, did you clean the brakes while you had the lines off?

Providing it's not super overful of fluid,

Then, maybe you had a sticky piston before and bleeding / extra pressure has caused it to pop out and not retract.

Anytime you have the lines off is a good idea to get the pistons out and clean any crud and dirt from the seals and pistons and they should work great.

If you pop the pistons out clean them up and inspect the seals, if there swollen and raggy then replace, if not just be careful when you remove them and they should go back in fine.

[bikemonkey]

No I just took the old lines off and fitted the new ones.

Looks like I'll be stripping my calipers then.
Will probably update on here with pics to ask advice etc as this is the first time I've touched hydraulic brakes!

[amorti]

As Mark has mentioned, did you clean the brakes while you had the lines off?

Providing it's not super overful of fluid,

Then, maybe you had a sticky piston before and bleeding / extra pressure has caused it to pop out and not retract.

Anytime you have the lines off is a good idea to get the pistons out and clean any crud and dirt from the seals and pistons and they should work great.

If you pop the pistons out clean them up and inspect the seals, if there swollen and raggy then replace, if not just be careful when you remove them and they should go back in fine.

Worth more careful investigation. Overfill the reservoir and the pistons can't return!

Cleaning brakes is easy if you remember a couple of things - use brass tools and brushes so's not to damage the alloy bodies or chrome plating too much; if it's not shiny it's not clean enough; put the seals back in the same orientation you removed them; if any seals need replacing, get OE.

To split calipers, first remove pistons - put a suitable sized flat spanner in to replicate a disc, use lever to pump all four pistons toward the middle. Do this on both sides, might need to top up the fluid to do it. Then remove the whole brake system so's not to get fluid everywhere. "Crack" the half bolts on the bike, or you'll not get them later. On the bench, split the calipers in half. Remove pistons WITHOUT scratching them. Don't get annoyed or you'll mark them then they're dead. Once all are out, carefully pick out the seals if they are in ok condition re-use them (at your own risk etc. etc.) but likely the dust seals will be shot. Use a brass toothbrush from wilko's etc. to clean out the grooves, perfect fit and doesn't damage the bores like steel does. Then when you're back to shiny, fit it back together.

That is all there is too it.

Mmm, shiny.

[Andy666]

Make sure you're using the correct thickness copper washers, and they space the banjos properly with the holes in the bolt. My front end locked up after the pads welded themselves to the discs...

[bikemonkey]

Cheers for the replies guys, found out its cheaper and easier to buy another set of calipers in good condition than go to the hassle of stripping my old ones and replacing seals etc.

I'd have to buy torx sockets for a start, then seals most likely (which aren't cheap as I'd want to go down the OE route).

And I'm getting impatient, still haven't rode this bike since I bought it December last year!

[Neosophist]

Cheers for the replies guys, found out its cheaper and easier to buy another set of calipers in good condition than go to the hassle of stripping my old ones and replacing seals etc.

I'd have to buy torx sockets for a start, then seals most likely (which aren't cheap as I'd want to go down the OE route).

And I'm getting impatient, still haven't rode this bike since I bought it December last year!

Rushing isn't going to get you good results

You only need one torx bit, not a set (you can buy them individually from many shops, even ebay etc)

I'd get them apart first and see what they are like.. it's a good chance that the dust seals are knackered, not the actual piston seal.

These can swell and jam up the piston, it also means you dont' need to buy as many seals.

If you buy a second hand set of calipers you might have to do it all again. For the same of one torx bit and a few seals you'll have peace of mind knowing they'll last a long time before they need another overhaul.

[bikemonkey]

Hmm, I suppose, what size is the torx I'll need?