LLCOOLJ Posted February 13, 2011 Report Share Posted February 13, 2011 Hi all, Is anyone running a ZX6R G1 98 track bike? If so what brakes you running? I have converted the original 6 pots to some 4 pots of a Bandit (Calipers were stripped and cleaned, with new braided lines), still i feel the braking isn't that good. So i have tired a radial MC of a 2005 ZX6R 05 and still the brake lever wasn't solid, i bleed the thing loads of time, used a mityvac and i'm sure there was no air in the system, but still the lever felt spongy. Now, i have just stuck on a Brembo 19x18 MC and still feels the same, maybe 20% better but not what i was expecting. I'm begining to think that there is a in compatability issue somewhere, i even treied putting back on the original 6 pots and same result, not a solid feel in the lever. Only thing i can think of is the discs are buggered, as i got 2 sets of wheels it happens on the other set too, so sort of rules out the discs. Any ideas? Cheers! Link to comment Share on other sites More sharing options...
lorenzo Posted February 13, 2011 Report Share Posted February 13, 2011 I've used that exact same set up, bandit 12 calipers and a zx6r master cylinder, on my zx7r, and I thought it was really good. I'm guessing that it's a problem with either the seals in the master cylinder or just a sneaky trapped pocket of air. You could either try bleeding the bolt on the top of the master cylinder, or get yourself one of them nifty bolts with a bleed nipple built in. Either way, and this is only my opinion, but your system, if it's working properly, is certainly the issue. I had hel lines on and I think it was ebc hh pads, if these make much difference. Link to comment Share on other sites More sharing options...
LLCOOLJ Posted February 13, 2011 Author Report Share Posted February 13, 2011 I've used that exact same set up, bandit 12 calipers and a zx6r master cylinder, on my zx7r, and I thought it was really good. I'm guessing that it's a problem with either the seals in the master cylinder or just a sneaky trapped pocket of air. You could either try bleeding the bolt on the top of the master cylinder, or get yourself one of them nifty bolts with a bleed nipple built in. Either way, and this is only my opinion, but your system, if it's working properly, is certainly the issue. I had hel lines on and I think it was ebc hh pads, if these make much difference. I've got SBK HS pads at the mo they seem ok for a while, then the lever become softer. I've bleed the system (calipers and MC) with a Mityvac so i doubt there is air in it, i have used 2 MC's so far and its the same, so i sort of ruled out the MC's. I ain't got a clue what it is??? Last resort is take it to a garage and get the air sucked out by one of the bleeders, which is run of compressed air. Link to comment Share on other sites More sharing options...
Instant Gymnast Posted February 13, 2011 Report Share Posted February 13, 2011 Have you cable tied the lever back to the bar over night? (obvious, I know sorry…) A very easy way to bleed brakes is to use a large syringe and silicone pipe to push the fluid from the calliper up to the m/c through the bleed nipple. If you still get no joy, then it looks like a hard ware problem and you need to start thinking about a seal kit in the callipers (these being the only constant when you have swapped the master cylinders) Link to comment Share on other sites More sharing options...
LLCOOLJ Posted February 13, 2011 Author Report Share Posted February 13, 2011 Have you cable tied the lever back to the bar over night? (obvious, I know sorry…) A very easy way to bleed brakes is to use a large syringe and silicone pipe to push the fluid from the calliper up to the m/c through the bleed nipple. If you still get no joy, then it looks like a hard ware problem and you need to start thinking about a seal kit in the callipers (these being the only constant when you have swapped the master cylinders) Yup, tied the lever overnight :-) But still no joy :-( I don't think its the calipers as i changed them back to the original 6 pots and still the same result. I begining to think there is some sneaky air in it (as Lorenzo said), but how do u get this out? I used a mityvac on it alrdy?? Used the old fashioned way too.. I'm Stumped.... Link to comment Share on other sites More sharing options...
lorenzo Posted February 14, 2011 Report Share Posted February 14, 2011 With my mityvac I've found that it's great at getting a system about 90% bled, and really quick from a completley dry system so it's ideal if you're putting on new lines etc, but it's not much cop at actually getting all of the air out. I will do most of the bleeding via the mityvac then finish it off with the mityvac hose left on the nipple and then do it by hand. It might be worth having a look at the area around the bleed nipples too, I've found that sometimes the seal isn't the best and you can get some fluid coming up past the threads. Pop a little layer of PTFE tape/plumbers tape round each of the bleed nipples thread and this should sort it out. You can get the tape from any DIY store and it's literally a pound or so, really cheap. Also, like I said, make sure you bleed the top banjo where it attaches to the master cylinder too. Squeeze the lever, put some kitchen roll round by the banjo bolt then crack the bolt open, just ever so slightly, so you feel the lever go a bit soft. As you push the lever in keep the bolt open until just before the lever reaches fully in, then shut the bolt, all the time maintaining your squeeze on the lever. Do this 3 or 4 times and you should get rid of any air that's left trapped up there. It's vital that you keep pressure on the lever at all times that the bolt is even slightly open though. The master cylinder is usually at an angle that makes the bolt the highest up point of the system, which is the reason why it's hard top get all of the air out from up there. Link to comment Share on other sites More sharing options...
LLCOOLJ Posted February 14, 2011 Author Report Share Posted February 14, 2011 With my mityvac I've found that it's great at getting a system about 90% bled, and really quick from a completley dry system so it's ideal if you're putting on new lines etc, but it's not much cop at actually getting all of the air out. I will do most of the bleeding via the mityvac then finish it off with the mityvac hose left on the nipple and then do it by hand. It might be worth having a look at the area around the bleed nipples too, I've found that sometimes the seal isn't the best and you can get some fluid coming up past the threads. Pop a little layer of PTFE tape/plumbers tape round each of the bleed nipples thread and this should sort it out. You can get the tape from any DIY store and it's literally a pound or so, really cheap. Also, like I said, make sure you bleed the top banjo where it attaches to the master cylinder too. Squeeze the lever, put some kitchen roll round by the banjo bolt then crack the bolt open, just ever so slightly, so you feel the lever go a bit soft. As you push the lever in keep the bolt open until just before the lever reaches fully in, then shut the bolt, all the time maintaining your squeeze on the lever. Do this 3 or 4 times and you should get rid of any air that's left trapped up there. It's vital that you keep pressure on the lever at all times that the bolt is even slightly open though. The master cylinder is usually at an angle that makes the bolt the highest up point of the system, which is the reason why it's hard top get all of the air out from up there. Yeah, i found the mityvac was good for a dry system, but bleeding i found the old fashioned way works the same. I have PFTE around the bleed nipple threads alrdy, whacked them on as i thought it maybe this causing the spongyness. When you mean the top banjo, do you mean the banjo which joins the two lines to the MC? Reason i ask is because i have a bleed nipple on the MC too, i have bled that as well, i thought the bleed nipple on the MC will eliminate me cracking open the banjo? This is mounted on the top of the MC , which means this will be the highest point? Link to comment Share on other sites More sharing options...
lorenzo Posted February 14, 2011 Report Share Posted February 14, 2011 When you mean the top banjo, do you mean the banjo which joins the two lines to the MC? Reason i ask is because i have a bleed nipple on the MC too, i have bled that as well, i thought the bleed nipple on the MC will eliminate me cracking open the banjo? This is mounted on the top of the MC , which means this will be the highest point? Yep, that's what I meant. The short answer is that there's 3 places where air is going to be, 2 calipers and the master cylinder, you've just got to work out which one. It's not unknown for air to be behind the pistons too, try pushing them all the way in then give it a go at bleeding the calipers again. Link to comment Share on other sites More sharing options...
LLCOOLJ Posted February 14, 2011 Author Report Share Posted February 14, 2011 Yep, that's what I meant. The short answer is that there's 3 places where air is going to be, 2 calipers and the master cylinder, you've just got to work out which one. It's not unknown for air to be behind the pistons too, try pushing them all the way in then give it a go at bleeding the calipers again. I will give the pistons a push back and see what happens. When i push the pistons back do i loosen the bleed nipple on the relevant caliper? Link to comment Share on other sites More sharing options...
LLCOOLJ Posted February 14, 2011 Author Report Share Posted February 14, 2011 Just been reading up on this seems and issue on the old ZX6R's http://kawasakiownersclub.com/topic/551508/1/ I might try the wooden block in between the pads and see if that works Link to comment Share on other sites More sharing options...
lorenzo Posted February 14, 2011 Report Share Posted February 14, 2011 I'd doubt if the explaination on there is 100% correct about the discs flexing, but certainly bleeding them with the pistons pushed back by a chunk of wood is going to be different to having the pistons half way out. Put your mityvac hose on but with no vacuum (so it's just there to catch any fluid), loosen the nipple slightly, then push the pistons right the way in. Now stick something in that is going to keep the pistons there. You could use a chunk of wood, I use a big fat screwdriver, but wehatever you've got that's not going to fall out and keeps the pistons firmly in place. Then bleed the caliper and next do the same on the other. Hopefully you're sorted. A nice test to see if you've got air in there or if it's something else is simply to pump your brake lever 4 or 5 times. If it starts firming up that's the air being compressed, you've got air in there and it's not bled fully. Link to comment Share on other sites More sharing options...
LLCOOLJ Posted February 14, 2011 Author Report Share Posted February 14, 2011 I'd doubt if the explaination on there is 100% correct about the discs flexing, but certainly bleeding them with the pistons pushed back by a chunk of wood is going to be different to having the pistons half way out. Put your mityvac hose on but with no vacuum (so it's just there to catch any fluid), loosen the nipple slightly, then push the pistons right the way in. Now stick something in that is going to keep the pistons there. You could use a chunk of wood, I use a big fat screwdriver, but wehatever you've got that's not going to fall out and keeps the pistons firmly in place. Then bleed the caliper and next do the same on the other. Hopefully you're sorted. A nice test to see if you've got air in there or if it's something else is simply to pump your brake lever 4 or 5 times. If it starts firming up that's the air being compressed, you've got air in there and it's not bled fully. Thanks! Will deffo do it tonight or tomorow night, let you know how i get on....... Fingers crossed.. Link to comment Share on other sites More sharing options...
Instant Gymnast Posted February 14, 2011 Report Share Posted February 14, 2011 Which does absolutely nothing. When the lever is pulled in you've created a completely sealed system that has isolated the master cylinder reservoir from the master cylinder/lines/calipers and where any any air in the system is now trapped with no way of escaping.... Oh well, its always worked for me! (As much as I would like to return with a witty and informed argument, I am unable...) Extra salt for me please! Link to comment Share on other sites More sharing options...
LLCOOLJ Posted February 14, 2011 Author Report Share Posted February 14, 2011 With my mityvac I've found that it's great at getting a system about 90% bled, and really quick from a completley dry system so it's ideal if you're putting on new lines etc, but it's not much cop at actually getting all of the air out. I will do most of the bleeding via the mityvac then finish it off with the mityvac hose left on the nipple and then do it by hand. It might be worth having a look at the area around the bleed nipples too, I've found that sometimes the seal isn't the best and you can get some fluid coming up past the threads. Pop a little layer of PTFE tape/plumbers tape round each of the bleed nipples thread and this should sort it out. You can get the tape from any DIY store and it's literally a pound or so, really cheap. Also, like I said, make sure you bleed the top banjo where it attaches to the master cylinder too. Squeeze the lever, put some kitchen roll round by the banjo bolt then crack the bolt open, just ever so slightly, so you feel the lever go a bit soft. As you push the lever in keep the bolt open until just before the lever reaches fully in, then shut the bolt, all the time maintaining your squeeze on the lever. Do this 3 or 4 times and you should get rid of any air that's left trapped up there. It's vital that you keep pressure on the lever at all times that the bolt is even slightly open though. The master cylinder is usually at an angle that makes the bolt the highest up point of the system, which is the reason why it's hard top get all of the air out from up there. Ok, latest update! I did all of the above and it feels a little bit better, still not 100% I reckon its the discs, when i chocked them up with a piece of wood (actually used an old brake pad) they felt alright. Feels like the discs are flexing when i squeeze the lever. Hmmmmm.. strange how both sets of my wheels have fooked discs???? In the initial squeeze of the lever there's like a cm play (take up of the bite), then it becomes a bit firmer. So, i think this is the best its gonna get :-( Thanks Lorenzo for ur help and the other comments left by the others :-) Link to comment Share on other sites More sharing options...
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