Rear R brakes problem

[300rman]

okay, so my rear brakes on my R.

i bleed them, and they work fine.
let the bike set for a few hours, and the brakes need to be bled again, otherwise, the nothing happens when you hit the brake.

it doesnt leak fluid, and it has been bled ALOT. any ideas guys?

[Ryan.]

are you using the right DOT? thats all i can think of...

[300rman]

are you using the right DOT? thats all i can think of...

i use DOT 3. have used it in everything, and never gave me issues. i think the boiling point of the fluid is different, but thats it. it would cause issues while braking for extended periods if it got hot, but i dont have that problem. only if the bike sits for a few hours, after its bled, its good all day to ride if you use the brake lol.

[Daddio]

When was the master cylinder last rebuilt. It kind of sounds like it has an internal leak. Can you get them to work by pumping up the brakes without bleeding them?

[SWIGIN]

yup, master cly is where id start

[300rman]

When was the master cylinder last rebuilt. It kind of sounds like it has an internal leak. Can you get them to work by pumping up the brakes without bleeding them?

sometimes, yes. sometimes, it has to be bled.

where can i get a cheap rebuild kit? Ebay?

[Daddio]

Dennis Kirk. Type in # 191751 and see what it brings up. It is made by K&L. That is what 1upfront has been using in his airfoolers. It isn't exactly the same as what is in them but it all fits and works well.

[toocheaptosmoke]

Good info to know Daddio.


I put a 400ex MC on mine, wasn't a direct bolt in though. But I got the whole MC for like 10 bucks. :w00t: Has worked good so far, except for that time I crashed into a shed... I swear my rear brakes didn't work, but could never get it to do it again. Could never have been rider error... :lol:

[Daddio]

Good info to know Daddio.


I put a 400ex MC on mine, wasn't a direct bolt in though. But I got the whole MC for like 10 bucks. :w00t: Has worked good so far, except for that time I crashed into a shed... I swear my rear brakes didn't work, but could never get it to do it again. Could never have been rider error... :lol:
It sounds like a nut was loose behind the handle bars.:naughty: :lol:

[sbjones73]

300r my old cr 250 did the same thing and it ended up being the master. it had an internal leak. replaced it and all was good.

[toocheaptosmoke]

It sounds like a nut was loose behind the handle bars.:naughty: :lol:

:lol: :lol:

[Macs]

Definatley the master cylinder. The Air foolers have a problem with them. I have rebuilt several and after 6 months i would begin to have one problem or another. I decided that it was a bad design and used a one off a TRX. Had to do a little modifing but not much. I payed $40 for two of them shipped. I sold one of the bikes but the other one has been going strong for 5 years without an issue. That was the only change from stock on the whole bike but it was well worth it.