Rear master cylinder rebuild

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banner001
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My Bike: ZXR400 L4
Location: Nuneaton

Rear master cylinder rebuild

Post by banner001 » Thu Apr 27, 2017 10:57 am

Started to take my rear MC apart for a strip and rebuild...remembered there wasn't a guide on here and the manual is woefully lacking in actual information...so i decided to make one. The fronts are pretty similar, so until i do one for there this will have to suffice.

1. Remove the brake line from the MC and the rear brake fluid reservoir, brake fluid is corrosive so cleanup any that is spilled. Then using a set of internal circlip pliers remove the circlip:
Image

2. You can then pull out the tube and its o-ring - this o-ring doesnt come in any of the rebuild kits ive seen:
Image

3. You now need to unscrew the locknut and then remove the clevis, this is what you use to set the position of the brake lever:
Image
You then remove the rubber boot - its just a push fit, if its covered in debris you can grab the top of it and "twist" it to break the seal...it will come out to reveal...

4. A circlip (notice all the crap thats gathered in there after 24 years without a service), this holds back a plunger and a metal washer, this can be difficult to remove depending on the level of encrustation down the barrel, if yours is beyond hope new plungers can be ordered from cradleys for ~£30:
Image

5. This is what you will be left with, give everything a good clean/wash/sonnication, buy a new seal kit and replace the "worm-drive" piston along with its seals and spring, and the rubber boot...assembly is the reverse of this procedure.
Image
UK ZXR 400 L4
UK ZXR 400 L3 track bike
1989 FZR 1000 EXUP-R streetfighter

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Miles
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Re: Rear master cylinder rebuild

Post by Miles » Thu Apr 27, 2017 3:37 pm

Good job banner!

Admin can we make this a sticky in the know your stuff or brake section?

Also what about a new sections with just guides like this in it? I.e.: carb rebuild guide etc

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banner001
Track day God
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Posts: 2137
Joined: Sat Sep 24, 2011 3:27 pm
My Bike: ZXR400 L4
Location: Nuneaton

Re: Rear master cylinder rebuild

Post by banner001 » Thu Apr 27, 2017 7:06 pm

Admin!

I am an admin :D

I'm not a fan of duplicate posts, but maybe we need an overarching "how to with pictures" thread in the how to bit...
UK ZXR 400 L4
UK ZXR 400 L3 track bike
1989 FZR 1000 EXUP-R streetfighter

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