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Front Master Cylinder Leaking

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24 Jul 2023 14:12 #887552 by MadMac74
Front Master Cylinder Leaking was created by MadMac74
Hey everyone , Its been a while I know , but life must go on ....
So gave it about an hour of searching , with no luck . So here goes ;

My '78 still runs like a champ, after the 810 Conversion , however after the usual Winter nap it took , I seem to have a Front master Cylinder leak. It gets worse the more I use it . In over 20 years of owning this bike ,this has never happened .
 So I figured  I should try and fix this .... I order a "NEW OEM " Master Cylinder on line . It arrived the other day , so I bench bled it and installed it in my bike. Do ya think I could get it bled ?? NO way , its like that "NEW" master cylinder is no good .   Kinda at my Wits end ...

'78 KZ650 C2,810 conversion,stock kz 750 cams,with a Blueprinted Head both from a '81 KZ 750. BS 34 Mikunis, Mac /Kerker 4 into 1 with custom 2" comp baffle. 3 rd owner
'02 ZRX1200R, 3rd owner
'83 XR200R, 3 rd owner
'84 V65 Sabre 3 rd owner

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  • Scirocco
  • Offline
  • Premium Member
  • Never change a running system
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24 Jul 2023 14:56 #887554 by Scirocco
Replied by Scirocco on topic Front Master Cylinder Leaking
Did you try the reverse bleeding methode with a syringe?
The following user(s) said Thank You: Nessism

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  • SWest
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  • Sustaining Member
  • 10 22 2014
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24 Jul 2023 15:51 #887557 by SWest
Replied by SWest on topic Front Master Cylinder Leaking
If I'm having trouble I use a piece of tubing connected to the bleed screw in a container 1/2 full of old fluid and try bleeding it again. If that doesn't work I loosen the connection at the caliper, squeeze the lever slowly until no air comes out then move on to the next higher connector doing the same thing as I go until all the air is out of the system. I have a rag at each point to keep the mess at a minimum. Sometimes air is trapped in the slave so I tie the lever closed until no tiny air bubbles come out of the bypass hole. 
Air bubbles can get trapped at tight angles so it's hard to get rid of the little buggers. 
Steve

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25 Jul 2023 08:37 - 25 Jul 2023 09:56 #887582 by martin_csr
Replied by martin_csr on topic Front Master Cylinder Leaking
Speed bleeders are handy.  I installed one on my caliper & it makes the job much easier since you don't have to keep opening & closing the bleeder nipple; the standard setup mentioned by SWest is still handy so that you can see the air move. 

Additionally, I usually disconnect the caliper, jam plastic shims between the pads, & elevate the caliper as high as it will go with the bleeder nipple pointing up; If you do it this way, be sure to shim the brake pads securely. you don't want a caliper piston popping out too far or something.
Last edit: 25 Jul 2023 09:56 by martin_csr.
The following user(s) said Thank You: slayer61

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