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front brake master cylinder

Posted: Sat Dec 31, 2011 1:21 pm
by djb123456
hi everyone,
bought a zxr l3 and just trying to sort out the front brake.
it only seems to start braking when the lever is just a few centimeters away from the bar.
ive bleeded the brakes and it hasnt made much of a difference.
so iam going to change the parts in the master cylinder could anyone post a pic of how to get it apart plz.

thanks :smt001

Re: front brake master cylinder

Posted: Sat Dec 31, 2011 2:40 pm
by cargo
You'll find a good exploded drawing in the manual.



http://www.zxrworld.co.uk/zxr400/manual.html

Re: front brake master cylinder

Posted: Mon Jan 02, 2012 5:39 pm
by hatatfatcat
poke!

Re: front brake master cylinder

Posted: Tue Jan 03, 2012 2:54 am
by Mori Man
What's the span adjuster set at ?

Re: front brake master cylinder

Posted: Tue Jan 03, 2012 4:30 am
by cargo
hatatfatcat wrote:poke!

Poking in an activity that is restricted to Facebook................any further poking on ZXRworld will result in a week long ban

Admin power...................... :excited :excited

Re: front brake master cylinder

Posted: Tue Jan 03, 2012 8:50 am
by Mori Man
cargo wrote: Poking in an activity that is restricted to Fanny ................ any further poking on ZXRworld with out video will result in a week long ban
:smt003

Re: front brake master cylinder

Posted: Tue Jan 03, 2012 11:42 am
by djb123456
Mori Man wrote:What's the span adjuster set at ?
i thinks its at 1. why would this affect it?

Re: front brake master cylinder

Posted: Tue Jan 03, 2012 5:52 pm
by hatatfatcat
cargo wrote:
hatatfatcat wrote:poke!

Poking in an activity that is restricted to Facebook................any further poking on ZXRworld will result in a week long ban

Admin power...................... :excited :excited
you started it with the txting

Re: front brake master cylinder

Posted: Tue Jan 03, 2012 6:01 pm
by Tirpitz
djb123456 wrote:
Mori Man wrote:What's the span adjuster set at ?
i thinks its at 1. why would this affect it?
Because it makes the lever further away or closer to the bar to start with, so adjusting the available travel.

IME the front brake is a PITA to bleed properly. You will usually find microscopic bubbles trapped in the lines, splitter and also at the MC. You won't get these clear by the usual method of pumping with the brake lever. Your best bet is to get a vacuum bleeder to draw fluid through - that works.

Another way (but which takes longer) is to bang all the lines with a spanner to try and dislodge the bubbles. Leave the bike overnight with the bars turned so that the MC banjo is at the highest point so that the air can collect there (you will also probably already have some air trapped there which you wont dislodge). Then in the morning BEFORE TOUCHING THE BRAKE LEVER AT ALL crack open the MC banjo THEN pull the lever gently to push out the air. Tighten up before releasing the lever. Repeat as necessary. That generally clears it. You may need to repeat this once you've run the bike on the road as you may find some remaining bubbles collect at the MC banjo again.

IME Kwak front brakes take a lot of mucking about to bleed properly. Not difficult but takes patience.

If you want to rebuild the MC it's easy. Once the lever is off remove the rubber dust boot from the end of the MC piston and you will see a circlip in the recess. Remove and the MC piston pulls out. A rebuild kit will comprise new piston and seals (one of which you need to fit to the piston yourself), spring and new boot. Don't waste money on the OEM item, the pattern one from Wemoto is excellent quality and works A1. Replace in reverse order, fill system and bleed as above.

If you've got OEM rubber brake lines on and the bike is several years old and these have not been replaced the brakes will probably be spongy no matter what you do. Rubber lines have a service life. Replace with braided - they last for ever.

Re: front brake master cylinder

Posted: Wed Jan 04, 2012 9:50 am
by djb123456
Tirpitz wrote:
djb123456 wrote:
Mori Man wrote:What's the span adjuster set at ?
i thinks its at 1. why would this affect it?
Because it makes the lever further away or closer to the bar to start with, so adjusting the available travel.

IME the front brake is a PITA to bleed properly. You will usually find microscopic bubbles trapped in the lines, splitter and also at the MC. You won't get these clear by the usual method of pumping with the brake lever. Your best bet is to get a vacuum bleeder to draw fluid through - that works.

Another way (but which takes longer) is to bang all the lines with a spanner to try and dislodge the bubbles. Leave the bike overnight with the bars turned so that the MC banjo is at the highest point so that the air can collect there (you will also probably already have some air trapped there which you wont dislodge). Then in the morning BEFORE TOUCHING THE BRAKE LEVER AT ALL crack open the MC banjo THEN pull the lever gently to push out the air. Tighten up before releasing the lever. Repeat as necessary. That generally clears it. You may need to repeat this once you've run the bike on the road as you may find some remaining bubbles collect at the MC banjo again.

IME Kwak front brakes take a lot of mucking about to bleed properly. Not difficult but takes patience.

If you want to rebuild the MC it's easy. Once the lever is off remove the rubber dust boot from the end of the MC piston and you will see a circlip in the recess. Remove and the MC piston pulls out. A rebuild kit will comprise new piston and seals (one of which you need to fit to the piston yourself), spring and new boot. Don't waste money on the OEM item, the pattern one from Wemoto is excellent quality and works A1. Replace in reverse order, fill system and bleed as above.

If you've got OEM rubber brake lines on and the bike is several years old and these have not been replaced the brakes will probably be spongy no matter what you do. Rubber lines have a service life. Replace with braided - they last for ever.


thanks Tirpitz. ive ordered the master cylinder repair kit and goodridge front race braided pipes. once ive fitted them ill vacuum bleed them and hope they work then.
no doubt ill find something else to work on after the brakes, it seems to be one step forward two steps back :smt012

thanks :smt001

Re: front brake master cylinder

Posted: Thu May 02, 2013 4:31 pm
by lacos
1have same sort of problem hell lines new seals in calipers got pressure but the leaver will come to the bar it gets firmer if i pump the lever a few times is this the master cylinder or have i still got air in the system ?????? thanks

Re: front brake master cylinder

Posted: Thu May 02, 2013 6:30 pm
by CaNsA
Helpful hint.

Put the bike on the sidestand, not a paddock stand,and turn the bars on full left lock when bleeding the brakes.
Any bubbles trapped in the m/c will rise into the res.

Re: front brake master cylinder

Posted: Thu May 02, 2013 7:37 pm
by lacos
well ive now tied the lever in the on position will leave over night then bleed them again and thanks