front brakes (bleeding)

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kemp2368
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front brakes (bleeding)

Postby kemp2368 » Thu May 09, 2013 12:17 pm

hi all,just taken bike for its mot,passed no problems :D
he picked up on the front brake lever feels a bit spongy
its a z model so has twin callipers
is there a right way to bleed them as i have been told several ways on how to bleed them
i have a load of tubing,and syringe,
i need to drain old fluid out as i have had bike for 4 years and not replaced it so dont no how long its been in
do you bleed 1 calliper at a time etc
thanks
cb650z,1979

Mainerider
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Re: front brakes (bleeding)

Postby Mainerider » Thu May 09, 2013 2:35 pm

The most effective and consistently successful method is to use a vacuum brake bleeder; looks like a plastic pistol with a transparent plastic container. Cost for a basic model is about $30 US and is readily available at any auto parts store.

Bleeding the right side (throttle) caliper first is the correct protocol.
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kemp2368
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Re: front brakes (bleeding)

Postby kemp2368 » Thu May 09, 2013 2:44 pm

Mainerider wrote:The most effective and consistently successful method is to use a vacuum brake bleeder; looks like a plastic pistol with a transparent plastic container. Cost for a basic model is about $30 US and is readily available at any auto parts store.

Bleeding the right side (throttle) caliper first is the correct protocol.

thanks :D
cb650z,1979

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JorgenL
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Re: front brakes (bleeding)

Postby JorgenL » Thu May 09, 2013 4:27 pm

Try opening the reservoir slightly so that it's vented but doesn't allow dust and debris to get in and tape the lever (or use rope) against the throttle. Let it sit over night. Remove the tape or rope and put back the reservoir lid.

Doesn't matter how I bleed the brakes I always get them spongy. Letting it sit overnight in the brake position lets air travel up into the reservoir and the brake is perfect.
It might not work for everyone but it's free to try.

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kemp2368
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Re: front brakes (bleeding)

Postby kemp2368 » Fri May 10, 2013 12:37 pm

JorgenL wrote:Try opening the reservoir slightly so that it's vented but doesn't allow dust and debris to get in and tape the lever (or use rope) against the throttle. Let it sit over night. Remove the tape or rope and put back the reservoir lid.

Doesn't matter how I bleed the brakes I always get them spongy. Letting it sit overnight in the brake position lets air travel up into the reservoir and the brake is perfect.
It might not work for everyone but it's free to try.

thanks for that i will try that
how much resistance should there be when pulling lever back ? as when im pulling it back there is alot
cb650z,1979

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kemp2368
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Re: front brakes (bleeding)

Postby kemp2368 » Sat May 11, 2013 4:58 am

kemp2368 wrote:
JorgenL wrote:Try opening the reservoir slightly so that it's vented but doesn't allow dust and debris to get in and tape the lever (or use rope) against the throttle. Let it sit over night. Remove the tape or rope and put back the reservoir lid.

Doesn't matter how I bleed the brakes I always get them spongy. Letting it sit overnight in the brake position lets air travel up into the reservoir and the brake is perfect.
It might not work for everyone but it's free to try.

thanks for that i will try that
how much resistance should there be when pulling lever back ? as when im pulling it back there is alot

ok tightened lid back on this morning and still feels spongy :(
looks like im going to have to bleed them
cb650z,1979

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Folsoml
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Re: front brakes (bleeding)

Postby Folsoml » Sat May 11, 2013 11:51 am

Do them one at a time, and start with the throttle side caliper. I take a little piece of clear tubing (mine is the drain tube that came with a new battery) and put it over the drain nipple. I undo the nipple and pump the brake handle until I see that new clear fluid is coming out of the tube (with no air bubbles). I then repeat for the other caliper. Make sure you keep an eye on the fluid level in your reservoir--you don't want to let the level get too low and start pumping air into your lines.

Can't say this is the "right" way to do it, but it's what I do.
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Mainerider
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Re: front brakes (bleeding)

Postby Mainerider » Sat May 11, 2013 2:17 pm

I refurbish a lot of these brakes; Keep in mind:

30 year-old technology; these werent exactly Brembo Monobloc setups to begin with...
30 year-old components; if the components are worn, just putting fresh fluid in is like filling up a 90 year-old with anabolic steroids: dont expect miracles in either scenario...

You may have worn master cylinder components, old and spongy non-stainless steel reinforced rubber hoses, worn caliper piston seals, or pitting on the piston, any of which would contribute to the spongy feel.

My advice? If you can't get an acceptable level of braking out of your brakes, first buy a new, replacement master cylinder (available on Ebay) ( don't waste your money on a rebuild kit) and see how much improvement you see. If braking is still poor, look at replacement SS braided lines.

Of course, disassembly, inspection and cleaning of your calipers is also essential...i would do this step first but I have a fair amount of experience and the right tools. In your case, start with the master cylinder.
Last edited by Mainerider on Sat May 11, 2013 2:43 pm, edited 1 time in total.
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kemp2368
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Re: front brakes (bleeding)

Postby kemp2368 » Sat May 11, 2013 2:32 pm

Mainerider wrote:I refurbish a lot of these brakes; Keep in mind:

30 year-old technology; these werent exactly Brembo Monobloc setups to begin with...
30 year-old components...

You may have worn master cylinder components, old and spongy non-stainless steel reinforced rubber hoses, and worn caliper piston seals, any of which would contribute to the spongy feel

My advice? If you can't get an acceptable level of braking out of these, first buy a replacement master cylinder (available on Ebay) ( don't waste your money on a rebuild kit) and see how much improvement you see. If braking is still poor, look at replacement SS braided lines.

Of course, disassembly and cleaning of your calipers is always a good idea...

hi there,good advice i feel
i was thinking the same ,34 years old components may be worn out,
think i will drain out old fluid and replace,then if no better get a new master cylinder as you say
all of them are original (so worn)
or just put up with the feel, as they still stop me and the lever does not get to the handlebars
cb650z,1979

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Volker_P
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Re: front brakes (bleeding)

Postby Volker_P » Tue May 14, 2013 3:31 am

Folsoml wrote:Do them one at a time, and start with the throttle side caliper. I take a little piece of clear tubing (mine is the drain tube that came with a new battery) and put it over the drain nipple. I undo the nipple and pump the brake handle until I see that new clear fluid is coming out of the tube (with no air bubbles).

One should mention that one closes the nipple before release of the lever to open it again for the next pump step then.

In any case it will feel still a bit spongy with these 30 year old rubber tubes even if perfectly bleeded and with new caliper seals.
I installed stainless steel lines some time ago and this made a real, feelable difference. I'd say it was worth it. :wink:
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kemp2368
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Re: front brakes (bleeding)

Postby kemp2368 » Tue May 14, 2013 6:17 pm

Volker_P wrote:
Folsoml wrote:Do them one at a time, and start with the throttle side caliper. I take a little piece of clear tubing (mine is the drain tube that came with a new battery) and put it over the drain nipple. I undo the nipple and pump the brake handle until I see that new clear fluid is coming out of the tube (with no air bubbles).

One should mention that one closes the nipple before release of the lever to open it again for the next pump step then.

In any case it will feel still a bit spongy with these 30 year old rubber tubes even if perfectly bleeded and with new caliper seals.
I installed stainless steel lines some time ago and this made a real, feelable difference. I'd say it was worth it. :wink:

thanks for the reply's 8)
so as a bit of advice should i replace my original hoses and master cylinder then bleed
or which is more likley do you all think?? hoses first? or cylinder? :)
cb650z,1979

Mainerider
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Re: front brakes (bleeding)

Postby Mainerider » Tue May 14, 2013 8:45 pm

Since bleeding is quick and inexpensive, I would do that first, preferably with a vacuum bleeder. If you have an acceptable outcome with just a bleed you will have saved yourself time and money...

By the way, Reading... isn't that Kate Winslet's home town?
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Volker_P
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Re: front brakes (bleeding)

Postby Volker_P » Wed May 15, 2013 1:56 am

Replacing 30 year old stock hoses will certainly make a feelable difference.

Cylinder only if rubber parts are significantly worn. Or if the rubbers are damaged in a way that will cause air ingress. The latter would result in brake lever getting spongy again soon after successful bleeding.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum

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kemp2368
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Re: front brakes (bleeding)

Postby kemp2368 » Wed May 15, 2013 12:31 pm

Mainerider wrote:Since bleeding is quick and inexpensive, I would do that first, preferably with a vacuum bleeder. If you have an acceptable outcome with just a bleed you will have saved yourself time and money...

By the way, Reading... isn't that Kate Winslet's home town?

yes she is from reading :D
i have just ordered this :D
http://www.ebay.co.uk/itm/270460572546? ... 1497.l2649
cb650z,1979

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kemp2368
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Re: front brakes (bleeding)

Postby kemp2368 » Wed May 15, 2013 12:32 pm

Volker_P wrote:Replacing 30 year old stock hoses will certainly make a feelable difference.

Cylinder only if rubber parts are significantly worn. Or if the rubbers are damaged in a way that will cause air ingress. The latter would result in brake lever getting spongy again soon after successful bleeding.

yes i am thinking the same ive just ordered these http://www.ebay.co.uk/itm/270460572546? ... 1497.l2649
then i will take it from there :D
cb650z,1979


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