Soft brakes.

[Davie_G71]

Right, this is becoming quite annoying.

I have a 97 600 GSXR SRAD. The brakes are less than good.

They have been bled to death and no signs of air. I tried tying the lever to the bar with marginal success, but the lever still has to be adjusted out to number one to keep it as far from the bas as pssible, other wise the lever hits the bar with no effort at all.

What could cause this? Is it braided lines time?
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Suzuki GSXR600 SRAD, 1997 & Kawasaki Z1000, 2003.

[Kickstart]

Hi

Would be tempted to strip and clean up the calipers first. Pop the pistons out, take the seals out and clean up thoroughly behind the seals.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Davie_G71]

Thanks Keith, but forgot to mention that i've recently done this. Most of the pistons were siezed so i stripped and cleaned them and put them all back together.

Ther were full of crud behind the seals.
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Suzuki GSXR600 SRAD, 1997 & Kawasaki Z1000, 2003.

[Ichy]

Did you replace the seals?

I have a similar problem with my bike. New pistons, seals, brake lines and pads. I've narrowed it down to either the master cylinder or the pads are just not right for the disc.

Are you losing any fluid? If the answer is no and you are confident the calipers are fine then it might be worth rebuild the master cylinder, or maybe try one off a different bike to see if it improves things? Very unlikely to be the hoses unless they have visible swelling or a hole in them.

No idea if its the right one.
https://cgi.ebay.co.uk/SUZUKI-MASTER-CYL-REBUILD-KIT-PART-NO59600-45860-GSXR_W0QQitemZ180341026459QQcmdZViewItemQQptZUK_Motorcycle_Parts?hash=item180341026459&_trksid=p3286.c0.m14&_trkparms=66%3A4|65%3A1|39%3A1|240%3A1318
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https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

[Davie_G71]

No, i didn't replace the seals as they all looked fine. I'm pretty sure none of the pistons are sticking any more.

I was also thinking that that it could be the master cylinder, but i'm not losing any fluid at all, anywhere.

Would a dodgy MC not result in some fluid loss?
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Suzuki GSXR600 SRAD, 1997 & Kawasaki Z1000, 2003.

[Kickstart]

[Davie_G71]

OK, sorry for yet more questions, but can someone explain how wear of the seals or cups or any of the internals would result in a soft lever? Is it just a case of the rubbers going soft and not giving enough resistance.
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Suzuki GSXR600 SRAD, 1997 & Kawasaki Z1000, 2003.

[Kickstart]

Hi

If the main seal is worn then it might give a soft lever, but I would expect it to just give no pressure. The seal in the master cylinder is shaped like a parachute, and under pressure will push out hard onto the walls of the cylinder.

One thing that is well worth trying is to pull the brakes hard, wrap a cloth around the top banjo bolt and crack it off a touch then retighten it. Air can get stuck in the top banjo and this can get rid of it (the cloth is there to catch any fluid sprayed out).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Davie_G71]

Thanks Keith, but again we've done the top banjo bolt as well.

I do get pressure, it's just very soft.

What i did notice is that i can pump it a few times and get good pressure, but if i leave the bike standing for say 3-5mins then i would have to pump it a few times to get the same pressure. It's very annoying.

I'm about to buy that re-build kit posted on ebay, but it just sayd for GSXR, GSX models etc, i can see a rebuild kit on wemoto that looks identical to the ebay one but will definately fit my bike, but is more expensive. I just want to exhaust all avenues before i buy something i may not need.

All the best,

David.
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Suzuki GSXR600 SRAD, 1997 & Kawasaki Z1000, 2003.

[Ichy]

In theory if the main seal is torn or just not sealing well it can provide some pressure, just not enough.

For bleeding I use a vacuum pump, never let me down and the only way I know of reliably getting fluid through new or empty pipes.

In line with what Keith mentioned about the banjo bolt on the MC, if you have a splitter its worth just doing the same with the bolts on there.

I've never tested a master cylinder before so can only suggest either changing it for a working one or maybe replacing the banjo with a normal bolt and seeing if it hold the pressure when you pull the lever?
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https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

[Davie_G71]

Right, on checking there are some slight differences between parts. THe ebay one listed is a 16mm kit, but for my bike according to another site it's a 14mm kit i need. So i need to check this first.

Ichy, i don't have a splitter, the lines go to one caliper then over to the other one, i could check those bolts i suppose.

Edit - good shout on replacing the banjo with a normal bolt.
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Suzuki GSXR600 SRAD, 1997 & Kawasaki Z1000, 2003.

[Kickstart]

Hi

I had a similar problem with the ZZR600. In the end after new caliper seals and pistons I landed up rebuilding the master cylinder and replacing the lines, and spending hours bleeding the brakes and still had a lever that was pretty soggy but which would build up pressure if pumped (but lose it after 5 seconds or so). I landed up getting replacement calipers.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Davie_G71]

Man. I could really do without replacing the calipers.
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Suzuki GSXR600 SRAD, 1997 & Kawasaki Z1000, 2003.

[MaybeGuy]

https://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MESELX:IT&item=140313854580

they were working when i was using them, but they'll need cleaning out because they warped my disks.

near new pads on them too.
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[Noxious89123]

[MaybeGuy]

split them, pop the pistons out, clean the pistons.
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[Davie_G71]

They would have had the pistons sticking, causing the disc to warp through heat.

I'm not replacing the calipers just yet, i can' see how they will be causing this.
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Suzuki GSXR600 SRAD, 1997 & Kawasaki Z1000, 2003.

[Noxious89123]

+1

Logically thinking, what could physically be wrong with them to cause a problem??

My brakes tend to be a little soft, but i attributed that to old rubber hoses. But if i pump the lever, they do gain pressure a bit of presure temporarily.

/confused/
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'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[Irezumi aka Reuben]

Do master cylinder seals. Had similar on my ZX6R, changed the MC seals as it was cheap after having fitted HEL lines. Hey presto the brakes were better than ever.

[Ichy]

[Noxious89123]

[Ichy]

They normally come as a kit, £15-£20. Follow the link posted about four from the top to see what they look like.


EDIT:
or look at the picture I just attached.
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https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

[Kickstart]

[Davie_G71]

I'm going to do the master cylinder with a kit. See if that helps.
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Suzuki GSXR600 SRAD, 1997 & Kawasaki Z1000, 2003.