gt32 Posted June 5, 2007 Report Share Posted June 5, 2007 Evening all. I wonder if anyone could offer a little advice. My bike's been laid up for a while and as a result of not using it the front disc brake has seized up. I thought that maybe the pads had stuck to the disc but it seems as though the plunger on the master cylinder has stuck in. Has anyone experienced this problem before? or have any idea on the best way to fix it. I'm reluctant to start stripping the lot down to find out whats stuck when I dont know what end (master cylinder or caliper pistons) are the problem. I would be grateful for any suggestions. Cheers Mark Quote Link to comment Share on other sites More sharing options...
dfwilson Posted June 6, 2007 Report Share Posted June 6, 2007 I had the same thing happen to my 03 SY-250. It is most likely crap that has lodged between the brake puck and the bore. Pull the front wheel off. Remove the brake pads. Push the puck on one side in as far as it will go and hold it there. Pump the brake carefully and push the other puck out just until the seal shows. Clean the puck and surrounding area with contact or brake cleaner. Push the puck back in and repeat on the other side. Re-assemble it and it should work fine. Hope this works. Doug Quote Link to comment Share on other sites More sharing options...
gt32 Posted June 6, 2007 Author Report Share Posted June 6, 2007 Hi Doug - thanks for the response. It looks like you've just decided what I am doing this weekend. It serves me right really for neglecting her for too long. Thanks for the help, I will let you know how I get on. Mark Quote Link to comment Share on other sites More sharing options...
peterb Posted June 9, 2007 Report Share Posted June 9, 2007 Hi Mark, Before you strip out the caliper pistons, try this first. Remove the caliper and work the pistons in and out using force from the master cylinder (not too much as the pistons will fall out) and, though I don't like using it here, WD40/CRC or whatever it is called where you live, sprayed onto the pistons to remove the muck while the piston moves out/in. To get the inwards movement, use a tyre lever or similar rounded tool to gently prise the pistons back into their housings. It's worked for me. Saves stripping the pistons out and bleeding the brake system. Bye, PeterB. Quote Link to comment Share on other sites More sharing options...
kevin j Posted June 10, 2007 Report Share Posted June 10, 2007 Don't use WD40 or oil on brake stuff: the seals/o-rings for glycol brake fluid are attacked by oil (and vice versa, nitrile seals are attacked by glycol) Use brake cleaner spray. But, since the front brake is so easy to bleed, I'd strip it all apart and clean and fix it right. I've also had lot of problems if the pads get glycol on them, they are toast. Tried cleaning, sanding, sanding with belt sander, and never get the right feel back. So, I am really careful on bleeding to not leak. Or best yet is pull the pads and put some bad ones in, or some spacers of plastic or masonite. Anyone have easier solutions to that? k Quote Link to comment Share on other sites More sharing options...
gt32 Posted September 2, 2008 Author Report Share Posted September 2, 2008 Evening all. Sorry to resurrect an old thread again, but after slinging the bike to the back of the garage for nearly a year and trying to forget about the seized brakes, I have finally faced up to it. Seeing as though so many of you offered advice in the first place, I thought you might like to know how it turned out... So, as most people mentioned, started at the easy end first. Removed pads sprayed the rest very liberally with brake cleaner, left over night. Hoped against hope that the brake fairies would have come overnight to fix it all. No joy. Tried brute force to push the pistons in, then swearing...... no joy. Threw a wobbler for a bit, then decided to check out the master cylinder end. Unfortunatly someone had been at the reservour cover before me munched the screw heads up and got The Hulk to tighten them.....que more swearing. Tried the bleed nipple, that made noises that foretold of an expensive snap......more swearing. At this point, I thought it best to seek professional advice, convinced that it was looking to be expensive with either a new caliper (apparently you cant get overhaul kits for Brembo's) or a new master cylinder or both Called into White Bros, wandered over to Alan the trials guru looking very crestfallen, with my battered brakeline in a washing up bowl and asked for his opinion. He kindly stripped the lot down for me to seek a diagonsis and rather than just telling me to replace bits (its quite an old bike) got to the krux of the problem straight away. The master cylinder valve was a huge chunk of rust, which had forced the brakes on and the rest, bleed nipple, caliper pistons etc had all just seized up slightly with underuse. He even managed to extract the mashed up reservour screws. Once he had extracted the valve, inspected the bore (slightly marked but not too bad) fitted a new valve, loosened off the bleed nipple (gas torch) backfilled the system and cleaned the whole lot up for me, he pumped the brakes a few times - click, pistons free!! Overall cost? about Quote Link to comment Share on other sites More sharing options...
peterb Posted September 4, 2008 Report Share Posted September 4, 2008 You don't often see that anymore, lads walking up Darlington high street with a washing up bowl. He's a really good bloke that Al isn't he. Bye, PeterB. Quote Link to comment Share on other sites More sharing options...
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