Hello all my friends just purchased a 2013 300 evo and the rear brake doesn't seem to be working properly. The foot brake just seems to go all the way down to the sump plate with very little effect. Has anyone had the same problem and a fix?

Many thanks

Are the brake pads low on material?... 2mm of material is the lower limit - if they are ok try bleeding the brake... plenty of tips on here already as to the best way to do that... if it’s still no good then you’ll need a new master cylinder piston kit... I suspect that’ll be the problem anyway... check the Caliper pistons for signs of leaking or corrosion... If the bike is new to you then if you change the calliper pistons as well and rear pads you’ll know the complete system is new and Shouldn’t give you any problems for a while. 

Don't bother re-kitting evo rear brake mcyl. high rate of failure... If you enjoy spending hours and hours of your time bleeding, testing, and scratching your head when it's still not right, by all means re-kit it

9 hours ago, thall1 said:

Are the brake pads low on material?... 2mm of material is the lower limit - if they are ok try bleeding the brake... plenty of tips on here already as to the best way to do that... if it’s still no good then you’ll need a new master cylinder piston kit... I suspect that’ll be the problem anyway... check the Caliper pistons for signs of leaking or corrosion... If the bike is new to you then if you change the calliper pistons as well and rear pads you’ll know the complete system is new and Shouldn’t give you any problems for a while. 

Thanks for the reply, the pads look good I'll try bleeding it today and see how I get on but I think it could be master cylinder.

If you replace the master cylinder the 2017 onwards one is a direct swap and has a better outer seal.

It sounds like it just needs bleeding though.

10 hours ago, totty79 said:

If you replace the master cylinder the 2017 onwards one is a direct swap and has a better outer seal.

It sounds like it just needs bleeding though.

I'm going to try bleeding it first thank you for your help.

Do read everything you can on bleeding before attempting it. It’s not easy so make full use of other people’s experience.

True but that’s how it becomes your experience.?

 OH, the funny thing is he probably just needs pads.

H

3 hours ago, lineaway said:

 OH, the funny thing is he probably just needs pads.

Hopefully. I put a new rear caliper on the '18 last month because the rear was acting strange after a hit. Replaced the bent disk but it still acted funky. Old caliper is still on the bench waiting to be disassembled and geeked at.

Edited June 30, 20206 yr by dan williams

Thanks for everyone's help I've put a set of pads in even thos nothing wrong with you old ones and bled the brake seems OK.

Just another quick question The front brake seems to be a bit stiff you pull the lever and its like the master cylinder piston is very slow to come back out and the don't have a full lever second time and the brake binds. Does that sound like a master cylinder repair kit needed?

Many thanks

sounds more like the calliper pistons are sticking?

21 hours ago, thall1 said:

sounds more like the calliper pistons are sticking?

I'll check them thanks for your help.

 

I just had a rear brake Evo experience, here is what i found, the master cylinder is only capable of operating the brake, it doesn't have enough travel to adjust the brake, ie push the pistons beyond normal operating travel to compensate for wear in the pads on it's own, I discovered this after doing a caliper clean, solution, stop one pad moving with feeler gauges between pad and disc, pump pedal, that brings the other piston out until it pushes the pad against the disc, then remove feelers, pump pedal again, there is then enough travel to get the other piston out against the pad and disc, it does seem to me that the Master cylinder can not adjust the brake automatically on it's own if there is a large gap between pads and discs, after say maintenance or pushing the pistons back to prep for new pads.