Rear disc brake help please!

vladthetodge · Two Stroke Sniffer Joined: 03 Mar 2015 Karma :

Hey guys. I noticed my rear brakes sticking, and sometimes freeing off with a tap or two on the pedal, so decided to take em apart and have a look see. I popped out the pads and cleaned the Pistons with brake fluid, and when one went in the other went out, with finger pressure. Pushing both back however needed a clamp and a bit more force, but not overly. I noticed that when I pushed them both back in together there was a click from the master cylinder. So put em back on the bike and tested, kind of worked, but if I inserted a little prodder to the outer pad and applied a little force the master cylinder clicked again. Repeat, same result. It seems to my poor mechanical mind that the issue is the cylinder not the Pistons. What do I do from here? Doesn't look like the master cylinder is able to be dismantled.

The bikes a daelim vjf125 roadsport.

Many thanks in advance

Raffles · World Chat Champion Joined: 14 Apr 2009 Karma :

vladthetodge · Two Stroke Sniffer Joined: 03 Mar 2015 Karma :

Ok, cool. Happy to have a go, any more detailed steps on if it can be cleaned out without replacing seals etc? I assume brake cleaner, can engine cleaner be used too? Do I grease owt? Sorry if it sounds noobish, confident on calipers and pads discs etc, just never had this type of problem before.

Raffles · World Chat Champion Joined: 14 Apr 2009 Karma :

Remove the unit from the bike to work on it.
Once the circlip has been removed from the bottom you should be able to push the piston out of the bore. To do this you may need to exert force, with a punch or something similar, through the hole that the banjo bolt was removed from. Do be careful not to score the bore whilst doing this.
Once everything is apart you should be able to clean (very gently) the piston and bore with some fine wire wool doused in brake fluid or light oil. Make sure that all remnants of the wire wool are removed when the job is completed.
Check the seals whilst you have it all apart and replace if damaged.
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vladthetodge · Two Stroke Sniffer Joined: 03 Mar 2015 Karma :

Thanks. Took a while. Now back on bike, brakes bled and working like they should. All adjusted and stopping like they should.

Cheers!