master clyinder leaking

[SFSPECBIKER79]

i just took the front wheel off and replaced tire then put wheel back on, then my master clyinder started leaking and dont know what happened. can any one help?

[Ken Talbot]

When you went to remove the calipers, you probably pushed each of the pistons back in a bit to get some clearance. The displaced brake fluid has to go somewhere, so it goes back into the master cylinder. If the cylinder was already on the high side of full, the extra fluid might have been enough to cause an overflow. Hope you didn't get any on your paint.

[SFSPECBIKER79]

thank ken , but the fluid came from the plunger closest to the end of the handle bars. it has never leaked until i changed tire and replaced wheel.

[Ken Talbot]

Any chance the fluid might have squeezed out from under the reservoir cap, and dribbled down so it looks like it is coming from the plunger area? Have you pulled the rubber boot back to see if the body of the plunger is actually wet up inside the end of the bore?

[SFSPECBIKER79]

no , i'll go do that now ,thanks be back in a bit . it seems to drip when i pump the brake handle.it also not building any pressure. i may have have messed things up when pumping them up to bleed them out. i read some where that pumping all the way against the handle grips is a no no.

[SFSPECBIKER79]

yelp it is leakin around the rubber at the plunger.what next?

[Dennyz]

Sounds like a rebuilt kit for the M/C is the next step. The piston (plunger) seal may have failed.

[DavesXS]

Rebuild kit=35$ or a brand new one from Mikesxs=79$
50$ difference.


Here is a pic of the new one installed and the BIG old ugly one next to it.
If you have the rams horn handle bars they have one at an angle too. (16mm is what you want)

Well worth the extra 50$ any day.





And here alone

[SFSPECBIKER79]

i like the looks of that,where could i find one like that ?appreciate the info cuz.right now i'm riding without them the fronts ,little scarry if you know what i mean.

[JACKHAMMER01]

You can get them here:

http://www.mikesxs.net/mikesxs-chass...ategory_id=1.2

Master Cylinder Assembly
Master Cylinder Assembly - 16mm bore. - Recommended for late dual disc Front
brakes on 1977-84 XS650’s or single front disc brake (1972-76 650’s). Yamaha
OEM type. Complete with brake lever, brake light switch, banjo bolt and washers.


Part #08-0265 $79.00 USD EA.

[powerram50]

the rebiuld kits on mikexs for 19$i know i need to get one.i have a small leak from the same spot.

[SFSPECBIKER79]

thanks, jackhammer i have one on order plus a few other things . be ready to ride soon. thanks to all others who looked and responded. this is a good site.

[SFSPECBIKER79]

new master cylinder

hey everybody i got my new master cylinder installed i got from mikes xs it realy looks good compared to the other one that was 30 year old.i would post picture ,but dont know how yet. thanks to all any way. when im riding ill be looking for my xs friends.

[dbeardslee]

Rowdyboy - to post a pic you have to upload to photobucket (free), or the like, and then link to the url. Photobucket has the http's for a direct link. Just copy and paste using the IMG button.